<prompt> OCPs are contraindicated in women receiving which of the following drug ?RifampicinEthambutolStreptomycinPyrazinamide  <response>: OCPs are contraindicated in patient on enzyme-inducing drugs like rifampicin, and antiepileptic except sodium valproate. Rifampicin induces cytochrome 450 ,increasing the hepatic hydroxlation of estrogen by which there is a fourfold increase in its metabolism. This causes clearance and deceased effect of estrogen. Reference: Shaws textbook of Gynaecology 17th edition,page 265. 