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Opioid toxicity and breakthrough analgesia — GPhC CRA MCQ

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HardCNS TherapeuticsOpioid toxicity and breakthrough analgesiaGPhC CRA

A patient taking morphine modified-release 30 mg twice daily for cancer pain is prescribed immediate-release morphine for breakthrough pain. He is also constipated and mildly drowsy, with respiratory rate 10/min at review. What is the most appropriate action?

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Correct answer: B — Seek urgent clinical review before supplying additional opioid because toxicity is possible

Respiratory rate 10/min with drowsiness suggests opioid toxicity, even in a patient with cancer pain. Additional opioid supply should be clarified urgently and the patient assessed, while constipation also needs appropriate prophylaxis or treatment. Crushing modified-release morphine can cause dose dumping and serious harm.

Reference: BNF; NICE CKS; Palliative care guidance