Hydromorphone for acute and chronic pain

While morphine is the gold standard for the management of severe cancer pain, some patients either do not achieve adequate analgesia, or suffer intolerable morphine-related toxicity. For these patients alternatives such as hydromorphone are recommended. However, there appear to be gaps in our understanding of the efficacy and potency of hydromorphone.

This review explores and assesses the evidence for the efficacy of hydromorphone in the management of pain.

Randomised trials which included hydromorphone were sought using electronic databases and by handsearching relevant journals. Date of the most recent search: February 2000.

RCTs which involved the administration of hydromorphone, for both acute and chronic pain conditions, in adults and children, were included.

A data extraction form was designed for the purpose of the review. The validity of each trial for inclusion was assessed using criteria described in the Cochrane Handbook. A grade was allocated to each study on the basis of allocation concealment. A checklist was used to assess blinding.

Forty three studies (2725 subjects) were included in the review. Approximately half of these studies received a low quality score. In addition, the heterogeneity of the studies precluded combination of data and results. A meta-analysis was therefore not possible. Of the 43 included studies, 11 (645 subjects) involved chronic pain conditions (all cancer) and 32 (2080 subjects) acute pain. Three studies were placebo-controlled. Of the remainder, hydromorphone was compared with other opioids (morphine, fentanyl, sufentanyl, meperidine, oxycodone, diamorphine), bupivicaine and with itself, using different formulations. The routes of administration included intravenous, oral, spinal, intramuscular and subcutaneous. Overall, hydromorphone appears to be a potent analgesic. The limited number of studies available suggest that there is little difference between morphine and hydromorphone in terms of analgesic efficacy, adverse effect profile and patient preference. However, as most studies involved small numbers of patients, it is difficult to determine real differences between both drugs. In the context of both acute and chronic pain, the issue of equi-analgesic ratios between morphine and hydromorphone was not resolved.

The studies included in this review were varied in terms of quality and methodology. However, the majority demonstrated that hydromorphone is a potent analgesic, that the clinical effects of hydromorphone appear to be dose-related, and that the adverse effect profile of hydromorphone is similar to that of other mu opioid receptor agonists.