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Theophylline interaction smoking cessation — GPhC CRA MCQ

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HardRespiratory TherapeuticsTheophylline interaction smoking cessationGPhC CRA

A patient stable on a named modified-release theophylline preparation is discharged on a different manufacturer’s modified-release product at the same stated daily dose. What should the pharmacist do?

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Correct answer: C — Maintain one theophylline brand and monitor exposure if switching is necessary

Maintain one theophylline brand and monitor exposure if switching is necessary: Modified-release theophylline preparations can have clinically important bioavailability differences; prescribing by brand reduces loss of control or toxicity. Substitute any brand with the same strength and daily dose: Modified-release profiles can differ despite the same stated strength. Reduce the dose by half whenever a different manufacturer is supplied: A fixed empirical reduction is not evidence-based and may cause therapeutic failure. Crush the replacement tablets to match the previous release profile: Crushing modified-release tablets can cause dose dumping and toxicity. Alternate manufacturers daily to average their modified-release characteristics: Alternating products creates variable exposure rather than a controlled conversion.

Reference: BNF: theophylline: https://bnf.nice.org.uk/drugs/theophylline/