Diamorphine hydrochloride

How it works

It is a prodrug rapidly converted to active opioids including morphine, which act as agonists at mu opioid receptors to produce analgesia and other opioid effects.

Prescribing in practice

• It is a potent opioid that can cause life-threatening respiratory depression and is liable to misuse and dependence, so prescribe with appropriate caution and observe controlled drug requirements.
• Its high solubility allows large amounts to be given in a small volume, which is useful for subcutaneous infusion in palliative care but increases the consequences of dosing errors.
• Doses should be reduced and titrated carefully in the elderly, the frail and those with renal or hepatic impairment, with naloxone available to reverse overdose.

Monitoring

Monitor pain control, level of sedation, respiratory rate and bowel function, with closer observation when initiating or increasing the dose.

Counselling the patient

• It may cause drowsiness and impair driving and skilled tasks.
• Constipation is common, so a laxative is often needed.
• Do not take with alcohol or other sedating medicines without advice.

Evidence & guidelines

Diamorphine is a long-established opioid analgesic supported by extensive clinical use in severe and palliative pain.