Doxycycline and antacid — GPhC CRA MCQ

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EasyInfectionsDoxycycline and antacidGPhC CRA

A patient taking doxycycline buys an aluminium-containing antacid for indigestion. What is the most important interaction to flag?

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Correct answer: C — Reduced doxycycline absorption

Multivalent cations reduce tetracycline absorption and doses should be separated. In this vignette, "Reduced doxycycline absorption" is the safest single best answer. The other options are less appropriate because they miss the key clinical risk, conflict with UK medicines guidance, or delay needed review.

Reference: BNF; NICE CKS