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Severe CAP with penicillin allergy — MRCP Part 1 MCQ

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HardRespiratorySevere CAP with penicillin allergyMRCP Part 1MRCEM SBAUKMLAPSA

A 52-year-old man is admitted with radiographically confirmed community-acquired pneumonia. He is newly confused, his respiratory rate is 34 breaths/min, blood pressure is 86/54 mmHg and serum urea is 12.4 mmol/L. He is vomiting and cannot retain oral medication. He previously developed hypotension, bronchospasm and generalised urticaria immediately after intravenous amoxicillin. His eGFR is 75 mL/min/1.73 m², and he has no history of epilepsy or fluoroquinolone-associated tendon injury. Which single antibiotic is the most appropriate initial empirical intravenous treatment?

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Correct answer: B — Intravenous levofloxacin

The correct answer is intravenous levofloxacin. His CURB65 score is 4, establishing high-severity CAP, and vomiting prevents oral treatment. NICE recommends levofloxacin as the alternative for high-severity CAP in adults with penicillin allergy; the intravenous route is appropriate here. Benzylpenicillin and co-amoxiclav are contraindicated by his convincing immediate penicillin anaphylaxis. Ceftriaxone is not the NICE-listed routine alternative for high-severity CAP with penicillin allergy and would require individual allergy and microbiology assessment rather than being the best empirical choice. Doxycycline monotherapy is an alternative for low- or moderate-severity CAP, not high-severity disease. Levofloxacin should still be checked for renal dosing, interactions, QT risk and fluoroquinolone contraindications because potentially disabling adverse effects restrict its use.

Reference: National Institute for Health and Care Excellence. NG250: Pneumonia—diagnosis and management, Table 1, antibiotics for treating community-acquired pneumonia in adults. 2025. https://www.nice.org.uk/guidance/ng250/chapter/Recommendations