Some of the views expressed in the following notes on newly approved products should be regarded as preliminary, as there may have been limited published data at the time of publication, and little experience in Australia of their safety or efficacy. However, the Editorial Executive Committee believes that comments made in good faith at an early stage may still be of value. Before new drugs are prescribed, the Committee believes it is important that more detailed information is obtained from the manufacturer's approved product information, a drug information centre or some other appropriate source.

Dilaudid (Knoll)
2 mg, 4 mg and 8 mg tablets
oral solution containing 1 mg/mL
ampoules containing 2 mg/mL, 10 mg/mL and 50 mg/5 mL
vials containing 500 mg/50 mL
Approved indication: moderate to severe pain
Australian Medicines Handbook Section 3.2

Hydromorphone is an opioid analgesic.1 It has been available overseas for a long time, but has not been marketed in Australia for many years.

Patients with chronic cancer pain, requiring an opioid analgesic, may tolerate one opioid better than another. Hydromorphone may be an alternative analgesic for patients troubled by the adverse effects of morphine.

Oral hydromorphone is rapidly absorbed, but first-pass metabolism reduces the bioavailability to 25%. The drug is rapidly and widely distributed throughout the body. Most of the absorbed dose is metabolised, so hydromorphone is contraindicated in hepatic impairment. As the major metabolite is excreted in the urine, the drug is also contraindicated in renal impairment. As the half-life of hydromorphone is 2-3 hours, the dose can be rapidly titrated.

The recommended starting dose for oral treatment is 2-4 mg every four hours. A daily oral dose of hydromorphone 6.5-7.5 mg is equivalent to 40-60 mg of morphine or 10-20 mg of methadone. An intramuscular or subcutaneous dose of hydromorphone 1.3-2.0 mg is equivalent to 10 mg of morphine or methadone. A high potency formulation is available for use in narcotic-tolerant patients; this should not be confused with the standard parenteral formulation as an overdose may result.

The adverse effects of hydromorphone resemble those of other opioids, e.g. dry mouth, dizziness, nausea and vomiting. Patients become dependent on hydromorphone, if it is taken regularly, within a few weeks. Tolerance can also be expected. Sudden withdrawal of treatment can cause a withdrawal syndrome.