A 24-year-old pregnant woman in her second trimester is diagnosed with sputum-positive pulmonary tuberculosis. The standard first-line oral drugs will be used, but one additional parenteral agent being considered must be avoided because of its effect on the fetus. Which drug and which fetal toxicity?

• A Ethambutol, fetal optic atrophy
• B Pyrazinamide, fetal hepatic necrosis
• C Rifampicin, neural tube defects
• D Streptomycin, congenital deafness from eighth nerve damage ✓

Explanation

Streptomycin crosses the placenta and damages the developing eighth cranial nerve, producing bilateral congenital sensorineural deafness; it should be avoided throughout pregnancy. By contrast, WHO and standard texts regard isoniazid, rifampicin, ethambutol and pyrazinamide as compatible with pregnancy, so ethambutol and pyrazinamide are safe distractors here despite their toxicities in non-pregnant patients.

Reference: Katzung Basic and Clinical Pharmacology, 15th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.