skip to main content

IE Prophylaxis Complex Allergy — ORE Part 1 MCQ

Instant feedback + full explanation. One question, done properly.

HardPharmacology & TherapeuticsIE Prophylaxis Complex AllergyORE Part 1

A 56-year-old patient with a prosthetic aortic valve requires an extraction. Following shared decision-making, antibiotic prophylaxis is to be given. He has immediate urticaria and bronchospasm after amoxicillin, and previously developed Clostridioides difficile infection after clindamycin. He can take oral medication and has no history of macrolide allergy or clinically relevant interacting medicines. Which single-dose oral prophylaxis regimen is most appropriate?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: B — Azithromycin 500 mg, 30–60 minutes before treatment

Explanation lettering: E = shown as A · A = shown as B · B = shown as E

A is correct. SDCEP recommends azithromycin 500 mg orally 30–60 minutes before an at-risk dental procedure as an alternative for adults with true penicillin allergy. The history of C. difficile infection after clindamycin makes clindamycin undesirable, but does not require prophylaxis to be abandoned because macrolide alternatives are available. Metronidazole is not an SDCEP regimen for infective-endocarditis prophylaxis. Co-amoxiclav contains amoxicillin and is contraindicated in this patient’s immediate penicillin allergy. Cefalexin is not listed by SDCEP as an oral prophylaxis option in penicillin allergy. No prophylaxis is inappropriate here because the patient is high risk, the procedure is an extraction, and prophylaxis has been agreed after shared decision-making.

Reference: Scottish Dental Clinical Effectiveness Programme (SDCEP). Antibiotic Prophylaxis Against Infective Endocarditis: Executive summary, Oral prophylaxis, 2026. https://www.antibioticprophylaxis.sdcep.org.uk/implementation-advice/executive-summary/executive-summary/