A 20 years old nulliparous woman is an oral contraceptives pills. She is currently diagnosed as having pulmonary tuberculosis which antituberculous drug decreases the effect of OCP.: (A) INH, (B) Pyrazinamide, (C) Ethambutol, (D) Rifampicin
Answer is D. Ans. is 'd' i.e.,. Rifampicin (Ref KDT in, 11/01, p. 754).There is not much to explain in this one as you know refampicin is a microsomal enzyme inducer which enhances its own metabolism as well as that of many drugs like - Warfarin*OCP* in) Digitoxin*Sulfonylureas*Steroids*