The Maudsley Prescribing Guidelines in Psychiatry
By Carol Paton, Shitij Kapur and David Taylor
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About this ebook
The evidence base for drug treatments in psychiatry ranges from meta-analyses and randomised controlled clinical trials to single case reports, and from NICE guidelines to individual SPCs. Where do you look for information when transferring a patient from one drug to another? Where do you find a clear overview when dealing with a complex patient (e.g, with co-morbid epilepsy or liver disease or HIV infection)? Where can you seek advice on prescribing psychotropics during pregnancy? The Maudsley Prescribing Guidelines in Psychiatry! The leading clinical reference for handling prescribing problems as encountered in daily practice and for formulating prescribing policy.
Evidence-based and written by experts
This book is the essential guide for anyone responsible for prescribing, dispensing or administering drugs for patients with mental health disorders. All the evidence has been reviewed and summarized succinctly by an expert team of psychiatrists and pharmacists.
New content and improved format
This new edition makes greater use of tables and boxes to facilitate quick reference and includes new sections on cytochrome-mediated interactions and psychiatric side effects of non-psychotropic drugs.
Clinically relevant
Chapters address plasma monitoring, schizophrenia, bipolar disorder, depression and anxiety, children and adolescents, substance abuse and special patient groups. Each section has a full reference list. The book covers prescribing drugs outside their licensed indications and their interaction with substances such as alcohol, nicotine and caffeine.
Useful for all levels of experience
Trainees will gain important information regarding the rational, safe and effective use of medications for patients with mental illness. Experienced clinicians will find excellent guidance regarding more complex issues that they may not encounter regularly.
Why the Maudsley Prescribing Guidelines in Psychiatry?
Long recognized as an international trailblazer in mental health care, the Maudsley Hospital earned its reputation for excellence in both in-patient and community care. It is highly regarded for its research, and pioneered the use of clinical neuroscience. You can trust The Maudsley Prescribing Guidelines in Psychiatry to be scientifically sound and clinically effective.
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The Maudsley Prescribing Guidelines in Psychiatry - Carol Paton
Chapter 1
Plasma level monitoring of psychotropic drugs and anticonvulsants
Plasma drug concentration or plasma ‘level’ monitoring is a process surrounded by some confusion and misunderstanding. Drug level monitoring, when appropriately used, is of considerable help in optimising treatment and assuring adherence. However, in psychiatry, as in other areas of medicine, plasma level determinations are frequently undertaken without good cause and results acted upon inappropriately.¹ Conversely, in other instances, plasma concentrations are underused.
Before taking a blood sample for plasma level assay, check the following.
Is there a clinically useful assay method available? Only a minority of drugs have available assays. The assay must be clinically validated and results available within a clinically useful timescale.
Is the drug at ‘steady state’? Plasma levels are usually meaningful only when samples are taken after steady-state levels have been achieved. This takes 4–5 drug half-lives.
Is the timing of the sample correct? Sampling time is vitally important for many but not all drugs. If the recommended sampling time is, say, 12 h post dose, then the sample should be taken 11–13 h post dose if possible; 10–14 h post dose, if absolutely necessary. For trough or ‘predose’ samples, take the blood sample immediately before the next dose is due. Do not, under any circumstances, withhold the next dose for more than 1 or (possibly) 2 h until a sample is taken. Withholding for longer than this will inevitably give a misleading result (it will give a lower result than ever seen in the usual, regular dosing), which may lead to an inappropriate dose increase. Sampling time is less critical with drugs with a long half-life (e.g. olanzapine) but, as an absolute minimum, prescribers should always record the time of sampling and time of last dose.
If a sample is not taken within 1–2 h of the required time, it has the potential to mislead rather than inform. The only exception to this is if toxicity is suspected – sampling at the time of suspected toxicity is obviously appropriate.
Will the level have any inherent meaning? Is there a target range of plasma levels? If so, then plasma levels (from samples taken at the right time) will usefully guide dosing. If there is not an accepted target range, plasma levels can only indicate adherence or potential toxicity. If the sample is being used to check compliance, bear in mind that a plasma level of zero indicates only that the drug has not been taken in the past several days. Plasma levels above zero may indicate erratic compliance, full compliance or even long-standing non-compliance disguised by recent taking of prescribed doses. Note also that target ranges have their limitations: patients may respond to lower levels than the quoted range and tolerate levels above the range; also, ranges quoted by different laboratories sometimes vary widely without explanation.
Is there a clear reason for plasma level determination? Only the following reasons are valid:
to confirm compliance (but see above)
if toxicity is suspected
if a pharmacokinetic drug interaction is suspected
if clinical response is difficult to assess directly (and where a target range of plasma levels has been established)
if the drug has a narrow therapeutic index and toxicity concerns are considerable.
Interpreting sample results
The basic rule for sample level interpretation is to act upon assay results in conjunction with reliable clinical observation (‘treat the patient, not the level’). For example, if a patient is responding adequately to a drug but has a plasma level below the accepted target range, then the dose should not normally be increased. If a patient has intolerable adverse effects but a plasma level within the target range, then a dose decrease may be appropriate.
Where a plasma level result is substantially different from previous results, a repeat sample is usually advised. Check dose, timing of dose and recent compliance but ensure, in particular, the correct timing of the sample. Many anomalous results are the consequence of changes in sample timing.
Table 1.1 shows the target ranges for some commonly prescribed psychotropic drugs.
Table 1.1 Interpreting plasma concentration sample results for psychotropic drugs
Table 1-1Table 1-1Amisulpride
Amisulpride plasma levels are closely related to dose with insufficient variation to recommend routine plasma level monitoring. Higher levels observed in women¹⁸–²⁰ and older patients¹⁸,²⁰ seem to have little significant clinical implication for either therapeutic response or adverse effects. A (trough) threshold for clinical response has been suggested to be approximately 100 μg/l;²¹ mean levels of 367 μg/l²⁰ have been noted in responders in individual studies. Adverse effects (notably extrapyramidal side-effects [EPS]) have been observed at mean levels of 336 μg/l,¹⁸ 377 μg/l²¹ and 395 μg/l.¹⁹ A plasma level threshold of below 320 μg/l has been found to predict avoidance of EPS.²¹ A review of the current literature²² has suggested an approximate range of 200–320 μg/l for optimal clinical response and avoidance of adverse effects.
In practice, amisulpride plasma level monitoring is rarely undertaken and few laboratories offer amisulpride assays. The dose–response relationship is sufficiently robust to obviate the need for plasma sampling within the licensed dose range; adverse effects are well managed by dose adjustment alone. Plasma level monitoring is best reserved for those in whom clinical response is poor, adherence is questioned and in whom drug interactions or physical illness may make adverse effects more likely.
Aripiprazole
Plasma level monitoring of aripiprazole is rarely carried out in practice. The dose–response relationship of aripiprazole is well established, with a plateau in clinical response and D2 dopamine occupancy seen at doses above approximately 10 mg/day.²³ Plasma levels of aripiprazole, its metabolite and the total moiety (parent plus metabolite) strongly relate linearly to dose, making it possible to predict, with some certainty, an approximate plasma level for a given dose.²⁴ Target plasma level ranges for optimal clinical response have been suggested as 146–254 μg/l²⁵ and 150–300 μg/l,²⁶ with adverse effects observed above 210 μg/l.²⁶ Interindividual variation in aripiprazole plasma levels has been observed but not fully investigated, although gender appears to have little influence.²⁷,²⁸ Age, metabolic enzyme genotype and interacting medications seem likely causes of variation²⁶–²⁹ but there are too few reports regarding their clinical implication to recommend specific monitoring in respect to factors. A putative range of 150–210 μg/l²⁴ has been suggested as a target for patients taking aripiprazole who are showing little or no clinical response or who have intolerable EPS. For reasons described here, plasma level monitoring is not advised in routine practice.
Clozapine
Clozapine plasma levels are broadly related to daily dose³⁰ but there is sufficient variation to make any precise prediction of plasma level impossible. Plasma levels are generally lower in younger patients, males³¹ and smokers³² and higher in Asians.³³ A series of algorithms has been developed for the approximate prediction of clozapine levels according to patient factors and these are strongly recommended.³⁴ Algorithms cannot, however, account for other influences on clozapine plasma levels such as changes in adherence, inflammation³⁵ and infection.³⁶
The plasma level threshold for acute response to clozapine has been suggested to be 200 μg/l,³⁷ 350 μg/l,³⁸–⁴⁰ 370 μg/l,⁴¹ 420 μg/l,⁴² 504 μg/l⁴³ and 550 μg/l.⁴⁴ Limited data suggest that a level of at least 200 μg/l is required to prevent relapse.⁴⁵ Substantial variation in clozapine plasma level may also predict relapse.⁴⁶
Despite these varied estimates of response threshold, plasma levels can be useful in optimising treatment. In those not responding to clozapine, dose should be adjusted to give plasma levels in the range 350–500 μg/l. Those not tolerating clozapine may benefit from a reduction to a dose giving plasma levels in this range. An upper limit to the clozapine target range has not been defined. Plasma levels do seem to predict electroencephalogram (EEG) changes⁴⁷,⁴⁸ and seizures occur more frequently in patients with levels above 1000 μg/l⁴⁹ so levels should probably be kept well below this. Other non-neurological clozapine-related adverse effects also seem to be related to plasma-level,⁵⁰ as might be expected. Note that clozapine metabolism may become saturated at higher doses: the ratio of clozapine to norclozapine increases with increasing plasma levels, suggesting saturation.⁵¹–⁵³ The effect of fluvoxamine also suggests that metabolism via CYP1A2 to norclozapine can be overwhelmed.⁵⁴
Placing an upper limit on the target range for clozapine levels may discourage potentially worthwhile dose increases within the licensed dose range. Before plasma levels were widely used, clozapine was fairly often given in doses up to 900 mg/day, with valproate being added when the dose reached 600 mg/day. It remains unclear whether using these high doses can benefit patients with plasma levels already above the accepted threshold. Nonetheless, it is prudent to use an anticonvulsant as prophylaxis against seizures and myoclonus when plasma levels are above 500–600 μg/l and certainly when levels approach 1000 μg/l.
Olanzapine
Plasma levels of olanzapine are linearly related to daily dose, but there is substantial variation,⁵⁵ with higher levels seen in women,⁴³ non-smokers⁵⁶ and those on enzyme-inhibiting drugs.⁵⁶,⁵⁷ With once-daily dosing, the threshold level for response in schizophrenia has been suggested to be 9.3 μg/l (trough sample),⁵⁸ 23.2 μg/l (12-h postdose sample)⁴³ and 23 μg/l at a mean of 13.5 h post dose.⁵⁹ There is evidence to suggest that levels greater than around 40 μg/l (12-h sampling) produce no further therapeutic benefit than lower levels.⁶⁰ Severe toxicity is uncommon but may be associated with levels above 100 μg/l, and death is occasionally seen at levels above 160 μg/l⁶¹ (albeit when other drugs or physical factors are relevant). A target range for therapeutic use of 20–40 μg/l (12-h postdose sample) has been proposed⁶² for schizophrenia; the range for mania is probably similar.⁶³
Significant weight gain seems most likely to occur in those with plasma levels above 20 μg/l.⁶⁴ Constipation, dry mouth and tachycardia also seem to be related to plasma level.⁶⁵
In practice, the dose of olanzapine should be governed by response and tolerability. Plasma level determinations should be reserved for those suspected of non-adherence or those not responding to the maximum licensed dose (at 20 mg/day, around 20% of patients will have olanzapine levels <20 μg/l).⁶⁶ In the latter case, dose may then be adjusted to give 12-h plasma levels of 20–40 μg/l.
Quetiapine (IR)
Dose of quetiapine is weakly related to trough plasma concentration.⁶⁷–⁶⁹ Mean levels reported within the dose range 150 mg/day to 800 mg/day range from 27 μg/l to 387 μg/l,⁶⁸,⁷⁰–⁷⁴ although the highest and lowest levels are not necessarily found at the lowest and highest doses. Age, gender and co-medication may contribute to the significant interindividual variance observed in therapeutic drug monitoring studies, with female gender,⁷⁴,⁷⁵ older age⁷³,⁷⁴ and CYP3A4-inhibiting drugs⁶⁸,⁷³,⁷⁴ likely to increase quetiapine concentration. Reports of these effects are conflicting⁷⁵–⁷⁸ and not sufficient to support the routine use of plasma level monitoring based on these factors alone. Thresholds for clinical response have been proposed as 77 μg/l⁷⁶,⁷⁷ and 50–100 μg/l;⁷⁸ EPS has been observed in females with levels in excess of 210 μg/l.⁷⁶,⁷⁷ Despite the substantial variation in plasma levels at each dose, there is insufficient evidence to suggest a target therapeutic range, so plasma level monitoring has little value.
Most current reports of quetiapine concentrations are from trough samples. Because of the short half-life of quetiapine, trough levels tend to drop to within a relatively small range regardless of dose and previous peak level. Thus peak plasma levels may be more closely related to dose and clinical response⁶⁹ although monitoring of such is not currently justified in the absence of an established peak plasma target range. Quetiapine has an established dose–response relationship and appears to be well tolerated at doses well beyond the licensed dose range.⁷⁹ In practice, dose adjustment should be based on patient response and tolerability.
Risperidone
Risperidone plasma levels are rarely measured in the UK and very few laboratories have developed assay methods for its determination. Plasma level monitoring is probably unproductive (dose–response is well described) except where compliance is in doubt and in such cases, measurement of prolactin will give some idea of compliance.
The therapeutic range for risperidone is generally agreed to be 20–60 μg/l of the active moiety (risperidone + 9-OH risperidone)⁸⁰,⁸¹ although other ranges (25–150 μg/l and 25–80 μg/l) have been proposed.⁸² Plasma levels of 20–60 μg/l are usually afforded by oral doses of between 3 mg and 6 mg a day.⁸⁰,⁸³–⁸⁵ Occupancy of striatal dopamine D2 receptors has been shown to be around 65% (the minimum required for therapeutic effect) at plasma levels of approximately 20 μg/l.⁸¹
Risperidone long-acting injection (25 mg/2 weeks) appears to result in plasma levels averaging between 4.4 and 22.7 μg/l.⁸⁴ Dopamine D2 occupancies at this dose have been variously estimated at between 25% and 71%.⁸¹,⁸⁶,⁸⁷ There is considerable interindividual variation around these mean values, with a substantial minority of patients with plasma levels above those shown. Nonetheless, these data do cast doubt on the efficacy of a dose of 25 mg/2 weeks⁸⁴ although it is noteworthy that there is some evidence that long-acting preparations are effective despite apparently subtherapeutic plasma levels and dopamine occupancies.⁸⁸
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74. Aichhorn W et al. Influence of age, gender, body weight and valproate comedication on quetiapine plasma concentrations. Int Clin Psychopharmacol 2006; 21:81–85.
75. Mauri MC et al. Two weeks’ quetiapine treatment for schizophrenia, drug-induced psychosis and borderline personality disorder: a naturalistic study with drug plasma levels. Expert Opin Pharmacother 2007; 8:2207–2213.
76. Dragicevic A, Muller MJ, Sachse J, Hartter S, Hiemke C. Therapeutic drug monitoring (TDM) of quetiapine. Lecture presented at the Symposium of the AGNP, October 8–10th 2003, Munich.
77. Dragicevic A, Sachse J, Hartter S, Hiemke C, Muller MJ. Serum concentrations of quetiapine and clinical effects. International Meeting on Pharmacovigilance in Psychiatry, Therapeutic Drug Monitoring and Pharmacogenetics of Psychotropic Drugs, September 1–3 2005, Lausanne, Switzerland.
78. Dragicevic A, Trotzauer D, Hiemke C, Muller MJ. Gender and age effects on quetiapine serum concentrations in patients with schizophrenia or schizoaffective disorders. Lecture presented at the 24th Symposium of the AGNP, October 5–8th 2005, Munich.
79. Sparshatt A et al. Quetiapine: dose–response relationship in schizophrenia. CNS Drugs 2008; 22:49–68.
80. Olesen OV et al. Serum concentrations and side effects in psychiatric patients during risperidone therapy. Ther Drug Monit 1998; 20:380–384.
81. Remington G et al. A PET study evaluating dopamine D2 receptor occupancy for long-acting injectable risperidone. Am J Psychiatry 2006; 163:396–401.
82. Seto K et al. Risperidone in schizophrenia: is there a role for therapeutic drug monitoring? Ther Drug Monit 2011; 33:275–283.
83. Lane HY et al. Risperidone in acutely exacerbated schizophrenia: dosing strategies and plasma levels. J Clin Psychiatry 2000; 61:209–214.
84. Taylor D. Risperidone long-acting injection in practice – more questions than answers? Acta Psychiatr Scand 2006; 114:1–2.
85. Nyberg S et al. Suggested minimal effective dose of risperidone based on PET-measured D2 and 5-HT2A receptor occupancy in schizophrenic patients. Am J Psychiatry 1999; 156:869–875.
86. Medori R et al. Plasma antipsychotic concentration and receptor occupancy, with special focus on risperidone long-acting injectable. Eur Neuropsychopharmacol 2006; 16:233–240.
87. Gefvert O et al. Pharmacokinetics and D2 receptor occupancy of long-acting injectable risperidone (Risperdal Consta™) in patients with schizophrenia. Int J Neuropsychopharmacol 2005; 8:27–36.
88. Nyberg S et al. D2 dopamine receptor occupancy during low-dose treatment with haloperidol decanoate. Am J Psychiatry 1995; 152:173–178.
Chapter 2
Schizophrenia
The National Institute for Health and Clinical Excellence (NICE) guideline for medicines adherence¹ recommends that patients should be as involved as possible in decisions about the choice of medicines that are prescribed for them, and that clinicians should be aware that illness beliefs and beliefs about medicines influence adherence. Consistent with this general advice that covers all of healthcare, the NICE guideline for schizophrenia emphasises the importance of patient choice rather than specifically recommending a class or individual antipsychotic as first-line treatment.²
This chapter covers the treatment of schizophrenia with antipsychotic drugs, the relative adverse effect profile of these drugs and how adverse effects can be managed.
Antipsychotic drugs
Antipsychotic drugs are effective in both the acute and maintenance treatment of schizophrenia and other psychotic disorders. They differ in their pharmacology, kinetics, overall efficacy/effectiveness and tolerability, but perhaps more importantly, response and tolerability differ between patients. This individual response means that there is no clear first-line antipsychotic suitable for all.
Relative efficacy
Further to the publication of CATIE³ and CUtLASS,⁴ the World Psychiatric Association reviewed the evidence relating to the relative efficacy of 51 first-generation antipsychotics (FGAs) and 11 second-generation antipsychotics (SGAs) and concluded that, if differences in extrapyramidal side-effects (EPS) could be minimised (by careful dosing) and anticholinergic use avoided, there is no convincing evidence to support any advantage of SGAs over FGAs.⁵ As a class, SGAs may have a lower propensity for EPS and tardive dyskinesia⁶ but this is somewhat offset by a higher propensity for metabolic side-effects.
When individual non-clozapine SGAs are compared with each other, it would appear that olanzapine is more effective than aripiprazole, risperidone, quetiapine and ziprasidone, and that risperidone has the edge over quetiapine and ziprasidone.⁷ FGA-controlled trials also suggest an advantage for olanzapine, risperidone and amisulpride over older drugs.⁸,⁹ The magnitude of these differences is small and must be weighed against the very different side-effect profiles associated with individual antipsychotics.
Both FGAs and SGAs are associated with a number of adverse effects. These include weight gain, dyslipidaemia, hyperprolactinaemia, sexual dysfunction, EPS, anticholinergic effects, venous thromboembolism (VTE),¹⁰ sedation and postural hypotension. The exact profile is drug specific (see individual sections on adverse effects), although comparative data are not robust.¹¹ Side-effects are a common reason for treatment discontinuation.¹² Patients do not always spontaneously report side-effects, however,¹³ and psychiatrists’ views of the prevalence and importance of adverse effects differ markedly from patient experience.¹⁴ Systematic enquiry along with a physical examination and appropriate biochemical tests is the only way accurately to assess their presence and severity or perceived severity. Patient-completed checklists such as the Glasgow Antipsychotic Side-effect Scale (GASS)¹⁵ or the Liverpool University Neuroleptic Side-Effect Ratings Scale (LUNSERS)¹⁶ can be a useful first step in this process.
Non-adherence to antipsychotic treatment is common, which makes the guaranteed medication delivery associated with depot preparations potentially advantageous.¹⁷ In comparison with oral antipsychotics, there is a strong suggestion that depots may be associated with better global outcome¹⁸ and a reduced risk of rehospitalisation.¹⁹–²¹
In patients whose symptoms have not responded adequately to sequential trials of two or more antipsychotic drugs, clozapine is the most effective treatment²²–²⁴ and its use in these circumstances is recommended by NICE.² The biological basis for the superior efficacy of clozapine is uncertain.²⁵ Olanzapine should probably be one of the two drugs used before clozapine.⁷,²⁶
References
1. National Institute for Health and Clinical Excellence. Medicines adherence: involving patients in decisions about prescribed medicines and supporting adherence. Clinical Guidance CG76. 2009. www.nice.org.uk/.
2. National Institute for Health and Clinical Excellence. Schizophrenia: core interventions in the treatment and management of schizophrenia in adults in primary and secondary care (update). Clinical Guidance 82. 2009. www.nice.org.uk/.
3. Lieberman JA et al. Effectiveness of antipsychotic drugs in patients with chronic schizophrenia. N Engl J Med 2005; 353:1209–1223.
4. Jones PB et al. Randomized controlled trial of the effect on Quality of Life of second- vs first-generation antipsychotic drugs in schizophrenia: Cost Utility of the Latest Antipsychotic Drugs in Schizophrenia Study (CUtLASS 1). Arch Gen Psychiatry 2006; 63:1079–1087.
5. Tandon R et al. World Psychiatric Association Pharmacopsychiatry Section statement on comparative effectiveness of antipsychotics in the treatment of schizophrenia. Schizophr Res 2008; 100:20–38.
6. Tarsy D et al. Epidemiology of tardive dyskinesia before and during the era of modern antipsychotic drugs. Handb Clin Neurol 2011; 100:601–616.
7. Leucht S et al. A meta-analysis of head-to-head comparisons of second-generation antipsychotics in the treatment of schizophrenia. Am J Psychiatry 2009; 166:152–163.
8. Davis JM et al. A meta-analysis of the efficacy of second-generation antipsychotics. Arch Gen Psychiatry 2003; 60:553–564.
9. Leucht S et al. Second-generation versus first-generation antipsychotic drugs for schizophrenia: a meta-analysis. Lancet 2009; 373:31–41.
10. Parker C et al. Antipsychotic drugs and risk of venous thromboembolism: nested case-control study. BMJ 2010; 341:c4245.
11. Pope A et al. Assessment of adverse effects in clinical studies of antipsychotic medication: survey of methods used. Br J Psychiatry 2010; 197:67–72.
12. Falkai P. Limitations of current therapies: why do patients switch therapies? Eur Neuropsychopharmacol 2008; 18(Suppl 3):S135–S139.
13. Yusufi B et al. Prevalence and nature of side effects during clozapine maintenance treatment and the relationship with clozapine dose and plasma concentration. Int Clin Psychopharmacol 2007; 22:238–243.
14. Day JC et al. A comparison of patients’ and prescribers’ beliefs about neuroleptic side-effects: prevalence, distress and causation. Acta Psychiatr Scand 1998; 97:93–97.
15. Waddell L et al. A new self-rating scale for detecting atypical or second-generation antipsychotic side effects. J Psychopharmacol 2008; 22:238–243.
16. Day JC et al. A self-rating scale for measuring neuroleptic side-effects. Validation in a group of schizophrenic patients. Br J Psychiatry 1995; 166:650–653.
17. Zhu B et al. Time to discontinuation of depot and oral first-generation antipsychotics in the usual care of schizophrenia. Psychiatr Serv 2008; 59:315–317.
18. Adams CE et al. Systematic meta-review of depot antipsychotic drugs for people with schizophrenia. Br J Psychiatry 2001; 179:290–299.
19. Schooler NR. Relapse and rehospitalization: comparing oral and depot antipsychotics. J Clin Psychiatry 2003; 64(Suppl 16):14–17.
20. Tiihonen J et al. Effectiveness of antipsychotic treatments in a nationwide cohort of patients in community care after first hospitalisation due to schizophrenia and schizoaffective disorder: observational follow-up study. BMJ 2006; 333:224.
21. Leucht C et al. Oral versus depot antipsychotic drugs for schizophrenia – a critical systematic review and meta-analysis of randomised long-term trials. Schizophr Res 2011; 127:83–92.
22. Kane J et al. Clozapine for the treatment-resistant schizophrenic. A double-blind comparison with chlorpromazine. Arch Gen Psychiatry 1988; 45:789–796.
23. McEvoy JP et al. Effectiveness of clozapine versus olanzapine, quetiapine, and risperidone in patients with chronic schizophrenia who did not respond to prior atypical antipsychotic treatment. Am J Psychiatry 2006; 163:600–610.
24. Lewis SW et al. Randomized controlled trial of effect of prescription of clozapine versus other second-generation antipsychotic drugs in resistant schizophrenia. Schizophr Bull 2006; 32:715–723.
25. Stone JM et al. Review: the biological basis of antipsychotic response in schizophrenia. J Psychopharmacol 2010; 24:953–964.
26. Agid O et al. An algorithm-based approach to first-episode schizophrenia: response rates over 3 prospective antipsychotic trials with a retrospective data analysis. J Clin Psychiatry 2011; 72(11):1439–1444.
Antipsychotic drugs: equivalent doses
Antipsychotic drugs vary greatly in potency (not the same as efficacy) and this is usually expressed as differences in ‘neuroleptic’ or ‘chlorpromazine’ ‘equivalents’. Some of the estimates relating to neuroleptic equivalents are based on early dopamine binding studies and some largely on clinical experience or even inspired guesswork. British National Formulary (BNF) maximum doses for antipsychotic drugs bear little relationship to their ‘neuroleptic equivalents’. Table 2.1 gives some approximate equivalent doses for conventional drugs.¹,² Values given should be seen as a rough guide when transferring from one conventional drug to another. An early review of progress is essential.
Table 2.1 Equivalent doses of conventional antipsychotic drugs
It is inappropriate to convert second-generation antipsychotic doses into ‘equivalents’ since the dose–response relationship is usually well defined for these drugs. Dosage guidelines are discussed under each individual drug. Those readers desperate to find chlorpromazine equivalents for the newer drugs are directed to the published articles listing such data.³,⁴
References
1. Foster P. Neuroleptic equivalence. Pharm J 1989; 243:431–432.
2. Atkins M, Burgess A, Bottomley C, Riccio M. Chlorpromazine equivalents: a consensus of opinion for both clinical and research implications. Psychiatr Bull 1997; 21:224–226.
3. Woods SW. Chlorpromazine equivalent doses for the newer atypical antipsychotics. J Clin Psychiatry 2003; 64:663–667.
4. Gardner DM, Murphy AL, O’Donnell H, Centorrino F, Baldessarini RJ. International consensus study of antipsychotic dosing. Am J Psychiatry 2010; 167:686–693.
Antipsychotic drugs: minimum effective doses
Table 2.2 suggests the minimum dose of antipsychotic likely to be effective in schizophrenia (first episode or relapse). At least some patients will respond to the dose suggested, although others may require higher doses. Given the variation in individual response, all doses should be considered approximate. Primary references are provided where available, but consensus opinion has also been used (as have standard texts such as the BNF and Summaries of Product Characteristics). Only oral treatment with commonly used drugs is covered.
Table 2.2 Minimum effective daily dose of antipsychotics
References
1. Oosthuizen P et al. Determining the optimal dose of haloperidol in first-episode psychosis. J Psychopharmacol 2001; 15:251–255.
2. McGorry PD. Recommended haloperidol and risperidone doses in first-episode psychosis. J Clin Psychiatry 1999; 60:794–795.
3. Waraich PS et al. Haloperidol dose for the acute phase of schizophrenia. Cochrane Database Syst Rev 2002; CD001951.
4. Schooler N et al. Risperidone and haloperidol in first-episode psychosis: a long-term randomized trial. Am J Psychiatry 2005; 162:947–953.
5. Keefe RS et al. Long-term neurocognitive effects of olanzapine or low-dose haloperidol in first-episode psychosis. Biol Psychiatry 2006; 59:97–105.
6. Soares BG et al. Sulpiride for schizophrenia. Cochrane Database Syst Rev 2000; CD001162.
7. Armenteros JL et al. Antipsychotics in early onset schizophrenia: systematic review and meta-analysis. Eur Child Adolesc Psychiatry 2006; 15:141–148.
8. Mota NE et al. Amisulpride for schizophrenia. Cochrane Database Syst Rev 2002; CD001357.
9. Puech A et al. Amisulpride, and atypical antipsychotic, in the treatment of acute episodes of schizophrenia: a dose-ranging study vs. haloperidol. The Amisulpride Study Group. Acta Psychiatr Scand 1998; 98:65–72.
10. Moller HJ et al. Improvement of acute exacerbations of schizophrenia with amisulpride: a comparison with haloperidol. PROD-ASLP Study Group. Psychopharmacology 1997; 132:396–401.
11. Sparshatt A et al. Amisulpride – dose, plasma concentration, occupancy and response: implications for therapeutic drug monitoring. Acta Psychiatr Scand 2009; 120:416–428.
12. Taylor D. Aripiprazole: a review of its pharmacology and clinical utility. Int J Clin Pract 2003; 57:49–54.
13. Cutler AJ et al. The efficacy and safety of lower doses of aripiprazole for the treatment of patients with acute exacerbation of schizophrenia. CNS Spectr 2006; 11:691–702.
14. Mace S et al. Aripiprazole: dose–response relationship in schizophrenia and schizoaffective disorder. CNS Drugs 2008; 23:773–780.
15. Sparshatt A et al. A systematic review of aripiprazole – dose, plasma concentration, receptor occupancy and response: implications for therapeutic drug monitoring. J Clin Psychiatry 2010; 17:1447–1456.
16. Citrome L. Role of sublingual asenapine in treatment of schizophrenia. Neuropsychiatr Dis Treat 2011; 7:325–339.
17. Crabtree BL et al. Iloperidone for the management of adults with schizophrenia. Clin Ther 2011; 33:330–345.
18. Sanger TM et al. Olanzapine versus haloperidol treatment in first-episode psychosis. Am J Psychiatry 1999; 156:79–87.
19. Kasper S. Risperidone and olanzapine: optimal dosing for efficacy and tolerability in patients with schizophrenia. Int Clin Psychopharmacol 1998; 13:253–262.
20. Small JG et al. Quetiapine in patients with schizophrenia. A high- and low-dose double-blind comparison with placebo. Seroquel Study Group. Arch Gen Psychiatry 1997; 54:549–557.
21. Peuskens J et al. A comparison of quetiapine and chlorpromazine in the treatment of schizophrenia. Acta Psychiatr Scand 1997; 96:265–273.
22. Arvanitis LA et al. Multiple fixed doses of ‘Seroquel’ (quetiapine) in patients with acute exacerbation of schizophrenia: a comparison with haloperidol and placebo. Biol Psychiatry 1997; 42:233–246.
23. Kopala LC et al. Treatment of a first episode of psychotic illness with quetiapine: an analysis of 2 year outcomes. Schizophr Res 2006; 81:29–39.
24. Sparshatt A et al. Quetiapine: dose–response relationship in schizophrenia. CNS Drugs 2008; 22:49–68.
25. Sparshatt A et al. Relationship between daily dose, plasma concentrations, dopamine receptor occupancy, and clinical response to quetiapine: a review. J Clin Psychiatry 2011; 72:1108–1123.
26. Lane HY et al. Risperidone in acutely exacerbated schizophrenia: dosing strategies and plasma levels. J Clin Psychiatry 2000; 61:209–214.
27. Williams R. Optimal dosing with risperidone: updated recommendations. J Clin Psychiatry 2001; 62:282–289.
28. Ezewuzie N et al. Establishing a dose–response relationship for oral risperidone in relapsed schizophrenia. J Psychopharmacol 2006; 20:86–90.
29. Lindstrom E et al. Sertindole: efficacy and safety in schizophrenia. Expert Opin Pharmacother 2006; 7:1825–1834.
30. Bagnall A et al. Ziprasidone for schizophrenia and severe mental illness. Cochrane Database Syst Rev 2000; CD001945.
31. Taylor D. Ziprasidone – an atypical antipsychotic. Pharm J 2001; 266:396–401.
32. Joyce AT et al. Effect of initial ziprasidone dose on length of therapy in schizophrenia. Schizophr Res 2006; 83:285–292.
Further reading
Davis JM et al. Dose response and dose equivalence of antipsychotics. J Clin Psychopharmacol 2004; 24:192–208.
Antipsychotic drugs: licensed maximum doses
Table 2.3 lists the UK licensed maximum doses of antipsychotics.
Table 2.3 Maximum licensed doses of antipsychotic drugs in the UK
New antipsychotic drugs
Asenapine
Asenapine has affinity for D2, 5HT2A, 5HT2C and α1/α2-adrenergic receptors, along with relatively low affinity for H1 and ACh receptors.¹ At a dose of 5 mg twice daily, asenapine has been demonstrated to be more effective than placebo in acute treatment of schizophrenia and more effective than risperidone in the treatment of negative symptoms,² perhaps through selective affinity for different dopamine pathways, most notably in the prefrontal cortex.³ In the longer term, at a modal dose of 10 mg twice daily, asenapine reduces relapse rates in schizophrenia⁴ and bipolar disorder.⁵ It is also effective in mania.⁶,⁷ Asenapine has less potential to raise prolactin than risperidone and may be associated with a lower risk of weight gain.⁸ It is, it seems, metabolically neutral and shows considerable advantage over olanzapine in this regard.⁹ Widespread use may be inhibited by the fact that asenapine is absorbed sublingually and not absorbed if swallowed.¹⁰ Licensed uses vary from country to country.
Iloperidone
Iloperidone is a D2/5HT2A antagonist with little activity at H1 and muscarinic receptors.¹¹ In short-term trials, iloperidone 4–24 mg/day was more effective than placebo and doses of 20–24 mg/day showed similar efficacy to haloperidol and risperidone.¹²,¹³ Motor-related adverse effects were rare. Iloperidone 24 mg/day showed similar efficacy and tolerability to ziprasidone 160 mg/day in a 4-week trial, with each drug producing similar changes in QTc (around 11 msec increase).¹⁴ In long-term treatment, iloperidone 4–16 mg/day was equivalent to haloperidol 5–20 mg/day in terms of relapse and QT changes (around 10 msec increase).¹⁵ Insomnia is the most commonly experienced adverse effect of iloperidone. Mean weight gain in 6-week trials was 2.6 kg; prolactin levels appear not to be affected.¹¹ The plasma half-life is about 18 h, allowing once-daily administration, although only twice-daily dosing is allowed in its US labelling.¹⁶
Lurasidone
Lurasidone is a D2/5HT2A/5HT7 receptor antagonist with minimal effects on muscarinic, H1 and 5HT2C receptors.¹⁷ It is given at a dose of 40–120 mg a day after food (which increases its absorption). At such doses it is as effective as olanzapine 15 mg/day¹⁸ and ziprasidone 160 mg/day.¹⁹ Lurasidone has limited potential for QT prolongation or weight gain. Main adverse effects are somnolence, akathisia and nausea (occurring in around 10–20% of study participants).¹⁷
Olanzapine pamoate
Olanzapine pamoate is the long-acting form of olanzapine which can be given every 2 or every 4 weeks. Dosage forms available are 210 mg, 300 mg and 405 mg: all provide 150 mg/ml olanzapine after reconstitution.
Dosing should be according to established oral olanzapine dosing or a target oral dose (i.e. a dose that might usually be prescribed to a particular patient). Manufacturer’s recommendations are that oral olanzapine should be used first to establish tolerability, response and dose requirements. Dose equivalences are shown in Table 2.4.²⁰
Table 2.4 Dose equivalence of oral olanzapine and olanzapine pamoate
Postinjection syndrome occurs after 0.07% of injections and is characterised by confusion, delirium and (shortly after) profound sedation.²¹ It is probably caused by partial intravasation of the parent molecule which allows dissociation and rapid release of olanzapine. Because of the risk of postinjection syndrome, all patients should be observed in a healthcare facility for 3 h after administration.²⁰ After this time, patients need not be monitored and may be allowed to return home if accompanied. Postinjection syndrome usually occurs within an hour of injection but can rarely be seen after 1–3 h (1 in 1000 injections) or after 3 h (1 in 10,000 injections).²⁰ Patients should be advised to be vigilant for signs and symptoms of postinjection syndrome.
References
1. Shahid M et al. Asenapine: a novel psychopharmacologic agent with a unique human receptor signature. J Psychopharmacol 2009; 23:65–73.
2. Potkin SG et al. Efficacy and tolerability of asenapine in acute schizophrenia: a placebo- and risperidone-controlled trial. J Clin Psychiatry 2007; 68:1492–1500.
3. Moran-Gates T. Long-term administration of asenapine causes differential regional and dose-related effects on dopamine receptor subtypes. Biol Psychiatry 2006; 59(Suppl 1):1475.
4. Kane JM et al. A randomized placebo-controlled trial of asenapine for the prevention of relapse of schizophrenia after long-term treatment. J Clin Psychiatry 2011; 72:349–355.
5. McIntyre RS. Asenapine: a review of acute and extension phase data in bipolar disorder. CNS Neurosci Ther 2010; 17:645–648.
6. McIntyre RS et al. A 3-week, randomized, placebo-controlled trial of asenapine in the treatment of acute mania in bipolar mania and mixed states. Bipolar Disord 2009; 11:673–686.
7. McIntyre RS et al. Asenapine in the treatment of acute mania in bipolar I disorder: a randomized, double-blind, placebo-controlled trial. J Affect Disord 2010; 122:27–38.
8. Potkin SG. Asenapine efficacy, safety and tolerability in the treatment of acute schizophrenia: a randomised. placebo- and risperidone- controlled trial. Biol Psychiatry 2006; 59(Suppl 1):1545.
9. McIntyre RS et al. Asenapine versus olanzapine in acute mania: a double-blind extension study. Bipolar Disord 2009; 11:815–826.
10. Gerrits M et al. Effect of absorption site on the pharmacokinetics of sublingual asenapine in healthy male subjects. Biopharm Drug Dispos 2010; 31:351–357.
11. Citrome L et al. Iloperidone for schizophrenia: a review of the efficacy and safety profile for this newly-commercialised second-generation antipsychotic. Int J Clin Pract 2009; 63:1237–1248.
12. Weiden PJ et al. Safety profile of iloperidone: a pooled analysis of 6-week acute-phase pivotal trials. J Clin Psychopharmacol 2008; 28:S12–S19.
13. Potkin SG et al. Efficacy of iloperidone in the treatment of schizophrenia: initial phase 3 studies. J Clin Psychopharmacol 2008; 28:S4–11.
14. Cutler AJ et al. Four-week, double-blind, placebo- and ziprasidone-controlled trial of iloperidone in patients with acute exacerbations of schizophrenia. J Clin Psychopharmacol 2008; 28:S20–S28.
15. Kane JM et al. Long-term efficacy and safety of iloperidone: results from 3 clinical trials for the treatment of schizophrenia. J Clin Psychopharmacol 2008; 28:S29–S35.
16. Crabtree BL et al. Iloperidone for the management of adults with schizophrenia. Clin Ther 2011; 33:330–345.
17. Citrome L. Lurasidone for schizophrenia: a review of the efficacy and safety profile for this newly approved second-generation antipsychotic. Int J Clin Pract 2011; 65:189–210.
18. Meltzer HY et al. Lurasidone in the treatment of schizophrenia: a randomized, double-blind, placebo- and olanzapine-controlled study. Am J Psychiatry 2011; 168:957–967.
19. Potkin SG et al. Double-blind comparison of the safety and efficacy of lurasidone and ziprasidone in clinically stable outpatients with schizophrenia or schizoaffective disorder. Schizophr Res 2011; 132:101–107.
20. Eli Lilly and Company Limited. Zypadhera 210 mg, 300 mg and 405 mg, powder and solvent for prolonged release suspension for injection. 2010. www.medicines.org.uk/.
21. Food and Drug Administration. Psychopharmacologic Drugs Advisory Committee Briefing Document – Zyprexa olanzapine pamoate (OP) depot. 2008. www.fda.gov.
New antipsychotic drugs: costs
Newer antipsychotics are relatively expensive medicines, although their benefits may make them cost-effective in practice. Table 2.5 gives the cost as of November 2011 of atypicals at their estimated lowest effective dose, their approximate average clinical dose and their licensed maximum dose. The table allows comparison of different doses of the same drug and of different drugs at any of the three doses. It is hoped that the table will encourage the use of lower doses of less expensive drugs, given equality in other respects and allowing for clinical requirements.
Table 2.5 Monthly cost per patient of newer antipsychotic drugs in the UK
Table 2-7Antipsychotic drugs: general principles of prescribing
The lowest possible dose should be used. For each patient, the dose should be titrated to the lowest known to be effective (see section on ‘Antipsychotic drugs: minimum effective doses’ in this chapter); dose increases should then take place only after 2 weeks of assessment during which the patient is clearly showing poor or no response. With depot medication, plasma levels rise for 6–12 weeks after initiation, even without a change in dose. Dose increases during this time are therefore inappropriate.
For the large majority of patients, the use of a singleantipsychotic (with or without additional mood stabiliser or sedatives) is recommended (see section on ‘Combined antipsychotic drugs’ in this chapter). Apart from exceptional circumstances (e.g. clozapine augmentation), antipsychotic polypharmacy should be avoided because of the risks associated with QT prolongation and sudden cardiac death.¹
Combinations of antipsychotics should be used only where response to a single antipsychotic (including clozapine) has been clearly demonstrated to be inadequate. In such cases, the effect of the combination against target symptoms and the side-effects should be carefully evaluated and documented. Where there is no clear benefit, treatment should revert to single antipsychotic therapy.
In general, antipsychotics should not be used as prn sedatives. Short courses of benzodiazepines or general sedatives (e.g. promethazine) are recommended.
Responses to antipsychotic drug treatment should be assessed using recognised rating scales and be documented in patients’ records.
Those receiving antipsychotics should undergo close monitoring of physical health (including blood pressure, pulse, electrocardiogram [ECG], plasma glucose and plasma lipids) (see section on ‘Antipsychotic drugs: monitoring of metabolic effects’ in this chapter).
References
1. Ray WA et al. Atypical antipsychotic drugs and the risk of sudden cardiac death. N Engl J Med 2009; 360:225–235.
Further reading
Pharmacovigilance Working Party. Public assessment report on neuroleptics and cardiac safety, in particular QT prolongation, cardiac arrhythmias, ventricular tachycardia and torsades de pointes. 2006. www.mhra.gov.uk.
National Institute for Health and Clinical Excellence guidelines for the treatment of schizophrenia¹
The 2009 NICE guidelines differ importantly from previous guidelines (see summary in Box 2.1). There is no longer an imperative to prescribe an ‘atypical’ as first-line treatment and it is now recommended only that clozapine be ‘offered’ (rather than prescribed) after the prior failure of two antipsychotics. Much emphasis is placed on involving patients and their carers in prescribing decisions. There is some evidence that this is rarely done² but that it can be done.³
Box 2.1 Summary of NICE guidance: treatment and management of schizophrenia
For people with newly diagnosed schizophrenia, offer oral antipsychotic medication. Provide information and discuss the benefits and side-effect profile of each drug with the service user. The choice of drug should be made by the service user and healthcare professional together, considering:
ch02fig001.epsBefore starting antipsychotic medication, offer the person with schizophrenia an electrocardiogram (ECG) if:
ch02fig001.epsTreatment with antipsychotic medication should be considered an explicit individual therapeutic trial. For each patient:
ch02fig001.epsMonitor and record the following regularly and systematically throughout treatment, but especially during titration:
ch02fig001.epsCarry out a trial of the medication at optimum dosage for 4–6 weeks (although half of this period is probably sufficient if no effect at all is seen).
Do not use a loading dose of antipsychotic medication (often referred to as ‘rapid neuroleptisation’) (this does not apply to loading doses of depot forms of olanzapine and paliperidone).
Do not initiate regular combined antipsychotic medication, except for short periods (for example, when changing medication).
If prescribing chlorpromazine, warn of its potential to cause skin photosensitivity. Advise using sunscreen if necessary.
Consider offering depot/long-acting injectable antipsychotic medication to people with schizophrenia:
ch02fig001.epsOffer clozapine to people with schizophrenia whose illness has not responded adequately to treatment despite the sequential use of adequate doses of at least two different antipsychotic drugs. At least one of the drugs should be a non-clozapine second-generation antipsychotic (see section on ‘Treatment algorithms for schizophrenia’ in this chapter; we recommend that one of the drugs should be olanzapine).
For people with schizophrenia whose illness has not responded adequately to clozapine at an optimised dose, healthcare professionals should establish prior compliance with optimised antipsychotic treatment (including measuring drug levels) and engagement with psychological treatment before adding a second antipsychotic to augment treatment with clozapine. An adequate trial of such an augmentation may need to be up to 8–10 weeks (recent data suggest 6 weeks may be enough⁴). Choose a drug that does not compound the common side-effects of clozapine.
References
1. National Institute for Health and Clinical Excellence. Schizophrenia: core interventions in the treatment and management of schizophrenia in adults in primary and secondary care (update). 2009. www.nice.org.uk/.
2. Olofinjana B et al. Antipsychotic drugs – information and choice: a patient survey. Psychiatr Bull 2005; 29:369–371.
3. Whiskey E et al. Evaluation of an antipsychotic information sheet for patients. Int J Psychiatry Clin Pract 2005; 9:264–270.
4. Taylor D et al. Augmentation of clozapine with a second antipsychotic. A meta analysis. Acta Psychiatr Scand 2011; epub ahead of print.
Treatment algorithms for schizophrenia
Figures 2.1–2.3 show algorithms for the treatment of schizophrenia in three groups of patients.
Figure 2.1 Treatment of first-episode schizophrenia.
ch02fig001.epsFigure 2.2 Treatment of relapse or acute exacerbation of schizophrenia (full adherence to medication confirmed).
ch02fig002.epsFigure 2.3 Treatment of relapse or acute exacerbation of schizophrenia (adherence doubtful or known to be poor).
ch02fig003.epsNotes on algorithms
First-generation drugs may be slightly less efficacious than some SGAs.³,⁴ FGAs should probably be reserved for second-line use because of the possibility of poorer outcome compared with FGAs and the higher risk of movement disorder, particularly tardive dyskinesia.⁵,⁶
Choice is based largely on comparative adverse effect profile and relative toxicity. Patients seem able to make informed choices based on these factors⁷,⁸ although in practice they may only very rarely be involved in drug choice.⁹
Where there is prior treatment failure (but not confirmed treatment refractoriness) olanzapine or risperidone may be better options than quetiapine.¹⁰ Because of the wealth of evidence suggesting its slight superiority over other antipsychotics, olanzapine should always be tried before clozapine unless contraindicated.¹¹–¹⁴
Where there is confirmed treatment resistance (failure to respond to at least two antipsychotics) evidence supporting the use of clozapine (and only clozapine) is overwhelming.¹⁵,¹⁶
References
1. Agid O et al. The ‘delayed onset’ of antipsychotic action – an idea whose time has come and gone. J Psychiatry Neurosci 2006; 31:93–100.
2. Agid O et al. An algorithm-based approach to first-episode schizophrenia: response rates over 3 prospective antipsychotic trials with a retrospective data analysis. J Clin Psychiatry 2011; 72(11):1439–1444.
3. Davis JM et al. A meta-analysis of the efficacy of second-generation antipsychotics. Arch Gen Psychiatry 2003; 60:553–564.
4. Leucht S et al. Second-generation versus first-generation antipsychotic drugs for schizophrenia: a meta-analysis. Lancet 2009; 373:31–41.
5. Schooler N et al. Risperidone and haloperidol in first-episode psychosis: a long-term randomized trial. Am J Psychiatry 2005; 162:947–953.
6. Oosthuizen PP et al. Incidence of tardive dyskinesia in first-episode psychosis patients treated with low-dose haloperidol. J Clin Psychiatry 2003; 64:1075–1080.
7. Whiskey E et al. Evaluation of an antipsychotic information sheet for patients. Int J Psychiatry Clin Pract 2005; 9:264–270.
8. Stroup TS et al. Results of phase 3 of the CATIE schizophrenia trial. Schizophr Res 2009; 107:1–12.
9. Olofinjana B et al. Antipsychotic drugs – information and choice: a patient survey. Psychiatr Bull 2005; 29:369–371.
10. Stroup TS et al. Effectiveness of olanzapine, quetiapine, risperidone, and ziprasidone in patients with chronic schizophrenia following discontinuation of a previous atypical antipsychotic. Am J Psychiatry 2006; 163:611–622.
11. Haro JM et al. Remission and relapse in the outpatient care of schizophrenia: three-year results from the Schizophrenia Outpatient Health Outcomes study. J Clin Psychopharmacol 2006; 26:571–578.
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13. Tiihonen J et al. Effectiveness of antipsychotic treatments in a nationwide cohort of patients in community care after first hospitalisation due to schizophrenia and schizoaffective disorder: observational follow-up study. BMJ 2006; 333:224.
14. Leucht S et al. A meta-analysis of head-to-head comparisons of second-generation antipsychotics in the treatment of schizophrenia. Am J Psychiatry 2009; 166:152–163.
15. McEvoy JP et al. Effectiveness of clozapine versus olanzapine, quetiapine, and risperidone in patients with chronic schizophrenia who did not respond to prior atypical antipsychotic treatment. Am J Psychiatry 2006; 163:600–610.
16. Lewis SW et al. Randomized controlled trial of effect of prescription of clozapine versus other second-generation antipsychotic drugs in resistant schizophrenia. Schizophr Bull 2006; 32:715–723.
Antipsychotic drugs: monitoring of metabolic effects
Table 2.6 summarises suggested parameters for monitoring for those receiving antipsychotics. More detail and background is provided in specific sections in this chapter.
Table 2.6 Monitoring metabolic parameters for patients receiving antipsychotic drugs. This table summarises suggested monitoring for those receiving antipsychotics. More detail and background are provided in specific sections in this chapter
Table 2-8Table 2-8Table 2-8References
1. Burckart GJ et al. Neutropenia following acute chlorpromazine ingestion. Clin Toxicol 1981; 18:797–801.
2. Grohmann R et al. Agranulocytosis and significant leucopenia with neuroleptic drugs: results from the AMUP program. Psychopharmacology 1989; 99(Suppl):S109–S112.
3. Esposito D et al. Risperidone-induced morning pseudoneutropenia. Am J Psychiatry 2005; 162:397.
4. Montgomery J. Ziprasidone-related agranulocytosis following olanzapine-induced neutropenia. Gen Hosp Psychiatry 2006; 28:83–85.
5. Cowan C et al. Leukopenia and neutropenia induced by quetiapine. Prog Neuropsychopharmacol Biol Psychiatry 2006; 31:101–107.
6. Buchman N et al. Olanzapine-induced leukopenia with human leukocyte antigen profiling. Int Clin Psychopharmacol 2001; 16:55–57.
7. Marder SR et al. Physical health monitoring of patients with schizophrenia. Am J Psychiatry 2004; 161:1334–1349.
8. Fenton WS et al. Medication-induced weight gain and dyslipidemia in patients with schizophrenia. Am J Psychiatry 2006; 163:1697–1704.
9. Weissman EM et al. Lipid monitoring in patients with schizophrenia prescribed second-generation antipsychotics. J Clin Psychiatry 2006; 67:1323–1326.
10. Cohn TA et al. Metabolic monitoring for patients treated with antipsychotic medications. Can J Psychiatry 2006; 51:492–501.
11. Paton C et al. Obesity, dyslipidaemias and smoking in an inpatient population treated with antipsychotic drugs. Acta Psychiatr Scand 2004; 110:299–305.
12. Taylor D et al. Undiagnosed impaired fasting glucose and diabetes mellitus amongst inpatients receiving antipsychotic drugs. J Psychopharmacol 2005; 19:182–186.
13. Citrome L et al. Incidence, prevalence, and surveillance for diabetes in New York State psychiatric hospitals, 1997–2004. Psychiatr Serv 2006; 57:1132–1139.
14. Novotny T et al. Monitoring of QT interval in patients treated with psychotropic drugs. Int J Cardiol 2007; 117(3):329–332.
15. Ray WA et al. Atypical antipsychotic drugs and the risk of sudden cardiac death. N Engl J Med 2009; 360:225–235.
16. Hummer M et al. Hepatotoxicity of clozapine. J Clin Psychopharmacol 1997; 17:314–317.
17. Erdogan A et al. Management of marked liver enzyme increase during clozapine treatment: a case report and review of the literature. Int J Psychiatry Med 2004; 34:83–89.
18. Regal RE et al. Phenothiazine-induced cholestatic jaundice. Clin Pharm 1987; 6:787–794.
19. Centorrino F et al. EEG abnormalities during treatment with typical and atypical antipsychotics. Am J Psychiatry 2002; 159:109–115.
20. Gross A et al. Clozapine-induced QEEG changes correlate with clinical response in schizophrenic patients: a prospective, longitudinal study. Pharmacopsychiatry 2004; 37:119–122.
21. Twaites BR et al. The safety of quetiapine: results of a post-marketing surveillance study on 1728 patients in England. J Psychopharmacol 2007; 21:392–399.
22. Kelly DL et al. Thyroid function in treatment-resistant schizophrenia patients treated with quetiapine, risperidone, or fluphenazine. J Clin Psychiatry 2005; 66:80–84.
Switching antipsychotic drugs because of poor tolerability
General recommendations for switching antipsychotics are shown in Table 2.7.
Table 2.7 General recommendations for switching antipsychotic drugs
References
1. Stanniland C et al. Tolerability of atypical antipsychotics. Drug Saf 2000; 22:195–214.
2. Tarsy D et al. Effects of newer antipsychotics on extrapyramidal function. CNS Drugs 2002; 16:23–45.
3. Caroff SN et al. Movement disorders associated with atypical antipsychotic drugs. J Clin Psychiatry 2002; 63(Suppl 4):12–19.
4. Lemmens P et al. A combined analysis of double-blind