The authors previously showed the precision of adaptive control of amikacin therapy in elderly patients. The present retrospective study evaluated the effects of such therapy on outcomes. 48 patients, aged 80 +/- 5 years, with estimated creatinine clearance (eCCR) of 48 +/- 15 ml/mn, received amikacin initial dosage of 13.3 +/- 3.5 mg/kg/d, alone or with other drugs. Efficacy outcomes were: E1 = changes in dosage during therapy; E2 = fever reduction within 3 days after therapy; E3 = eradication of infection by culture data; E4 = reduction of white blood cell count (WCB) to normal; E5 = overall recovery. Toxicity outcomes were: T1 = subjective ototoxicity; T2 = nephrotoxicity, variation of serum creatinine low (between 18 et 44 mumol/l) or high (over 0.5 mg/dl).
Results: E1: final dose = 11.8 +/- 5.1 mg/kg/d (NS), 57% reduced, 33% increased, during 15.1 +/- 9.3 days in therapy, with 88% having effective peaks over 15 micrograms/ml. E2: fever reduced within 3 days 16/37; after 12/37; no change, 9/37. E3: cultures became negative, 13/28. E4: WBC fell early, 10/21; late, 7/21; no change, 2/21. E5: recovery 36; death, 8; change in therapy, 3. T1: no clinical signs of ototoxicity. T2: low(+), 9/51; low(-), 11/51; high(-), 7/51. final eCCR: 48 +/- 14 ml/mn (NS); no nephrotoxicity. These results suggest that adaptive control of amikacin regimens yields good efficacy and avoid toxicity in the Elderly. However, prospective controlled clinical trials should be done for confirmation.