Drugs That Increase the ****bolism of OCs
Herbal Supplements: Because most people think of herbal supplements as natural, many assume that they are harmless. One herb is believed to decrease the effectiveness of OCs.
St. John's wort, used to treat depression, has been shown to induce CYP3A4, increasing the ****bolism of hormones that can lead to intermenstrual or irregular bleeding.7,15,16 Pharmacists should inform patients of the adverse effects and recommend using St. John's wort with another form of contraception.

Drugs That Decrease the ****bolism of OCs

Herbal Supplements

Several herbal supplements are thought to have an additive effect on OCs. Saw palmetto, soy, and red clover are thought to increase the adverse effects of estrogen by acting as natural estrogens or by having antiestrogen effects and are not recommended for concomitant use.16,19 Grapefruit juice taken along with OCs can increase OC plasma levels by altering the degradation of estradiol and its ****bolites.
Thus, the bioavailable levels of estradiol are increased.16,20,21 Cat's claw, chamomile, echinacea, and ****enseal could cause increased levels because they are inhibitors of CYP3A4, but this has not yet been clinically proven.
15 Women may differ in their sensititivity to increased or decreased ****bolism of estrogen. Those who are more sensitive to hormonal changes should exercise caution when using these medications or herbal supplements concurrently with OCs.