CONCOMITANT USE OF CONJUGATED ESTROGENS AND MICRONIZED PROGESTERONE INCREASED HDL-C AND TRIGLYCARIDES AND DECREASED LDL-C COMPARED TO PLACEBO AND IMPAIR GLUCOSE TOLERNCE. FAILURE OF CONTRACEPTION WITH PHENOBARBITONE, PHENYTOIN,PRIMIDONE, CARBAMAZEPINE, DICHLORALPHENAZONE, RIFAMPICIN,VIT B6 AND BROAD SPECTRUM ANTIBIOTICS. COMBINATION WITH ETHINYLOESTRADIOL INCREASES INSULIN REQUIREMENT AND REDUCED EFFICACY OF ORAL ANTICOAGULANTS. REDUCES CLEARANCE OF CORTICOSTEROIDS, ALPRAZOLAM SO ENHANCES ITS EFFECT. INCREASES TOXICITY OF CYCLOSPORIN. DECREASED CLEARANCE OF XANTHINES. INCREASED CLEARANCE OF PARACETAMOL, MORPHINE, CLOFIBRATE. CIGARETTE SMOKING INCREASES THE RISK OF SERIOUS CARDIOVASCULAR SIDE EFFECTS FROM ORAL CONTRACEPTIVE USE. THIS RISK INCREASES WITH AGE AND WITH HEAVY SMOKING