Hydromorphone is a micro receptor agonist opioid. According to WHO recommendations, hydromorphone is to be classified in step III of pain therapy. An oral formulation with a prolonged duration of action of 12 hours has been evaluated only recently. The controlled release capsule is especially suited for the regular twice a day administration in cases of severe and persistent pain. The oral formulation of hydromorphone increases the number of opioid analgesics available for pain therapy in step III. Hydromorphone is recommended when morphine fails to produce sufficient pain relief (despite increase of doses) or causes intolerable side effects (despite treatment of symptoms). In principle, no differences in efficacy of morphine and hydromorphone are to be expected. However, clinical experience shows that changing one opioid analgesic to another one can improve the treatment of patients so that hydromorphone may replace another opioid analgesic to which a patient fails to respond well or develops side effects. The dose of hydromorphone equivalent to 2 times 30 mg controlled release morphine is about 2 times 4 mg. The values for the absorption, bioavailability and maximum plasma concentration after the administration of controlled release hydromorphone every 12 hours -of three times the dose- are equivalent to those of an immediate release tablet given every 4 hours. In several open label and controlled studies, hydromorphone proved to be of good efficacy in the treatment of acute and persistent pain, especially in patients with severe cancer pain. With regard to the incidence of side effects, no significant differences between morphine and hydromorphone could be established. In general, the side effects of hydromorphone are typical for opioid analgesics.
Discussion: In conclusion, controlled release hydromorphone seems to be well suited for the control of severe chronic pain when given twice daily.