mavacamten will lessen the level or result of ethinylestradiol by impacting hepatic/intestinal enzyme CYP3A4 metabolism. Steer clear of or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten may possibly decrease systemic exposures of ethinyl estradiol and progestin, which can result in contraceptive failure or a r