<prompt> OCPs are CI in pts receiving:RifampicinEthambutolStreptomycinPyrazinamide  <response>: Ans. is a, i.e. RifampicinRef: KDT 6thed, p317; Novak 14thed, p276Interactions of OCPs with other Drugs.Effect of other drugs on OCPs:Drugs reducing the effectiveness of OCPDrugs which increase the plasma level of steroids of OCP RifampicinQ CarbamazepineQ Phenytoin Ascorbic acid Acetaminophen Antifungals like- Griseofulvin- Ketoconazole- ItraconazoleInduce synthesis of cytochromeP450 enzymes in liver. Ampicillin TetracyclineKill gut bacteria and cause hydrolysis of steroid glucuronides in intestine. 