OCP fails when used with all except: (LQ)
a. Aspiring is acetyl-salicyclic acid and is not involved in OCP failure.
b. Tetracyclins kill the bacteria responsible for enterohepatic circulation of OCPs.
c. Phenytoin and rifampin are both potent enzyme inducers.
d. These will naturally, accelerate metabolism of OCPs leading to failure of OCPs.