Which drug is avoided during lactation?

• A. Methotrexate
• B. Hydroxychloroquine
• C. Sulfasalazine
• D. Leflunomide

Answer: (A)

The main concept here is medication safety during breastfeeding and which drugs are avoided because they can transfer into breast milk and harm the infant. Methotrexate is avoided during lactation because it is a folate antagonist that is excreted into breast milk and can cause serious toxicity in a nursing infant, including bone marrow suppression and hepatotoxicity. Because of these potential dangers, methotrexate is not compatible with breastfeeding, and a switch to a safer therapy or cessation of breastfeeding is advised if methotrexate is necessary for the mother.

In contrast, hydroxychloroquine passes into breast milk in only small amounts and is generally considered safe for breastfeeding, with routine monitoring. Sulfasalazine is also commonly deemed compatible with lactation, though some clinicians watch for effects related to its metabolites. Leflunomide has a long half-life and is typically avoided in lactation due to prolonged presence in the infant; if exposure occurs, a washout procedure may be needed.