mavacamten will lessen the level or result of ethinylestradiol by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Progestin and ethinyl estradiol are CYP3A4 substrates. Mavacamten might minimize systemic exposures of ethinyl estradiol and progestin, which may produce contraceptive failure or a rise in breakthro