Not recommended in women w/ severe asthma uncontrolled by oral glucocorticoids. Endometrial changes. Reduction in menstrual blood loss or amenorrhea. Not recommended w/ concomitant use of progestagen-only pills, progestagen-releasing IUD or combined OC pills & co-administration w/ moderate (eg, erythromycin, grapefruit juice, verapamil) or potent (eg, ketoconazole, ritonavir, nefazodone, itraconazole, telithromycin, clarithromycin) CYP3A4 inhibitors & potent CYP3A4 inducers (eg, rifampicin, rifabutin, carbamazepine, oxcarbazepine, phenytoin, fosphenytoin, phenobarb, primidone, St. John's wort, efavirenz, nevirapine, long-term use of ritonavir). May affect ability to drive & use machines. Not recommended in severe renal & moderate or severe hepatic impairment. Childn.