social, psychological and medical aspects of morphine use in palliative care are so different from that of drug abuse that comparisons are inappropriate. Dose reduction, when required, e.g. after relief of pain by palliative radiotherapy or nerve block, should, of course, be gradual; abrupt withdrawal (accidental) has been found to cause only a mild withdrawal syndrome.
• Acquired tolerance is dealt with by increasing the dose. There is no need for an arbitrary maximum dose.
• Transfer from the oral to the subcutaneous route may become necessary, e.g. due to difficult swallowing, vomiting. Diamorphine (heroin, preferred because it is more soluble than morphine) can be delivered by a portable syringe driver with minimal discomfort. The dose should be one-third the oral dose (4-hourly swallowed).
• A self-adhesive skin patch formulation which releases the opioid fentanyl (25 mg/h for 72 h) transdermally is also available for pain relief in palliative care.
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