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Sulfasalazine Male Fertility — SCE Rheumatology MCQ

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ModerateRheumatology PharmacologySulfasalazine Male FertilitySCE Rheumatology

A 34-year-old man with rheumatoid arthritis has been taking sulfasalazine for 8 months. His disease is well controlled, and he asks about the possible effect of treatment on his fertility because he and his partner are planning a pregnancy. Which statement is most accurate?

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Reveal the answer and explanation

Correct answer: B — It may cause reversible oligospermia, usually recovering 2–3 months after withdrawal.

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

Sulfasalazine can impair semen quality, particularly by reducing sperm concentration; reduced motility and abnormal morphology have also been reported. This can cause temporary male subfertility. The effect is reversible, and the UK SmPC states that oligospermia and infertility generally reverse within 2–3 months after withdrawal, approximately one spermatogenic cycle. It does not characteristically cause isolated loss of libido or erectile dysfunction, so A and D are incorrect. Unlike the gonadotoxicity associated with agents such as cyclophosphamide, the effect is not usually permanent, excluding B. There is no evidence that sulfasalazine improves sperm production, excluding E. The original numerical claim of an effect in up to 80% of men was removed because contemporary product information lists the frequency as unknown.

Reference: Pfizer Limited. Sulfasalazine 500 mg Tablets, Summary of Product Characteristics, sections 4.4 and 4.8; revised August 2025. https://www.medicines.org.uk/emc/product/15886/smpc