of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.ceftibutenMonitor Closely (1)ceftibuten will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.cefuroximeMonitor Closely (1)cefuroxime will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.cenobamateMonitor Closely (4)cenobamate will decrease the level or effect of levonorgestrel oral by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP3A4 substrate, as needed, when coadministered with cenobamate. cenobamate will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP3A4 substrate, as needed, when coadministered with cenobamate. cenobamate will decrease the level or effect of ethinylestradiol by unspecified interaction mechanism. Modify Therapy/Monitor Closely. Advise women to use additional or alternative non-hormonal birth control when concomitantly using cenobamate with oral contraceptives. cenobamate will decrease the level or effect of levonorgestrel oral by unspecified interaction mechanism. Modify Therapy/Monitor Closely. Advise women to use additional or alternative non-hormonal birth control when concomitantly using cenobamate with oral contraceptives.cephalexinMonitor Closely (1)cephalexin will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.ceritinibMonitor Closely (2)ceritinib will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. ceritinib will increase the level or effect of levonorgestrel oral by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.chloramphenicolMonitor Closely (1)chloramphenicol will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.cimetidineMonitor Closely (1)cimetidine will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.ciprofloxacinMonitor Closely (1)ciprofloxacin will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.clarithromycinMonitor Closely (1)clarithromycin will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Modify Therapy/Monitor Closely.Minor (1)ethinylestradiol will increase the level or effect of clarithromycin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.clindamycinMonitor Closely (1)clindamycin will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.clobazamMonitor Closely (2)clobazam will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Clobazam is a weak CYP3A4 inducer; effectiveness of hormonal contraceptives may be diminished when given concurrently with clobazam. Additional non-hormonal forms of contraception are recommended. clobazam will decrease the level or effect of levonorgestrel oral by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Clobazam is a weak CYP3A4 inducer; effectiveness of hormonal contraceptives may be diminished when given concurrently with clobazam. Additional non-hormonal forms of contraception are recommended.clomipramineMinor (1)ethinylestradiol will increase the level or effect of clomipramine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.clonazepamMonitor Closely (1)ethinylestradiol will increase the level or effect of clonazepam by Mechanism: decreasing metabolism. Use Caution/Monitor. Ethinyl estradiol may inhibit the clearance of benzodiazepines that undergo oxidation, thereby increasing serum concentrations of concomitantly administered benzodiazepines.conivaptanSerious - Use Alternative (1)conivaptan will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.crofelemerMonitor Closely (1)crofelemer increases levels of levonorgestrel oral by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Crofelemer has the potential to inhibit CYP3A4 at concentrations expected in the gut; unlikely to inhibit systemically because minimally absorbed.cyclophosphamideMinor (2)cyclophosphamide will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. cyclophosphamide will increase the level or effect of levonorgestrel oral by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.cyclosporineMonitor Closely (2)ethinylestradiol increases levels of cyclosporine by unknown mechanism. Use Caution/Monitor. levonorgestrel oral, cyclosporine. Either increases levels of the other by decreasing metabolism. Use Caution/Monitor. Combined oral contraceptives containing EE may inhibit the metabolism and increase plasma concentrations of cyclosporine.dabrafenibMonitor Closely (2)dabrafenib will decrease the level or effect of levonorgestrel oral by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. dabrafenib will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.dalteparinSerious - Use Alternative (1)levonorgestrel oral, dalteparin. Either decreases effects of the other by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Risk of thromboembolic disorders.darunavirMonitor Closely (1)darunavir will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Significant changes (increase or decrease) can occur in estrogen plasma levels. Efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended. dasatinibMonitor Closely (1)ethinylestradiol will increase the level or effect of dasatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.deferasiroxMonitor Closely (1)deferasirox will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.demeclocyclineMonitor Closely (1)demeclocycline will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.desipramineMinor (1)ethinylestradiol, desipramine. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Oxidative metabolism of TCAs may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Potential for increased TCA adverse effects.dexamethasoneMonitor Closely (1)dexamethasone decreases levels of levonorgestrel oral by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)dexamethasone will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.diazepamMonitor Closely (1)ethinylestradiol will increase the level or effect of diazepam by Mechanism: decreasing metabolism. Use Caution/Monitor. Ethinyl estradiol may inhibit the clearance of benzodiazepines that undergo oxidation, thereby increasing serum concentrations of concomitantly administered benzodiazepines.dicloxacillinMonitor Closely (1)dicloxacillin will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.dosulepinMinor (1)ethinylestradiol, dosulepin. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Oxidative metabolism of TCAs may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Potential for increased TCA adverse effects.doxepinMinor (1)ethinylestradiol, doxepin. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Oxidative metabolism of TCAs may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Potential for increased TCA adverse effects.doxycyclineMonitor Closely (1)doxycycline will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.duloxetineMinor (1)ethinylestradiol will increase the level or effect of duloxetine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.efavirenzMonitor Closely (1)efavirenz decreases levels of levonorgestrel oral by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.elagolixMonitor Closely (2)elagolix decreases levels of levonorgestrel oral by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak-to-moderate CYP3A4 inducer. Monitor CYP3A substrates if coadministered. Consider increasing CYP3A substrate dose if needed. elagolix will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak-to-moderate CYP3A4 inducer. Monitor CYP3A substrates if coadministered. Consider increasing CYP3A substrate dose if needed.Serious - Use Alternative (2)levonorgestrel oral decreases effects of elagolix by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Based on the mechanism of action of elagolix, estrogen-containing contraceptives are expected to reduce elagolix efficacy. Effects of progestin-only contraceptives on the efficacy of elagolix is unknown. Advise women to use nonhormonal contraceptives during treatment with elagolix and for 1 week after discontinuing elagolix. ethinylestradiol decreases effects of elagolix by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Based on the mechanism of action of elagolix, estrogen-containing contraceptives are expected to reduce elagolix efficacy. Effects of progestin-only contraceptives on the efficacy of elagolix is unknown. Advise women to use nonhormonal contraceptives during treatment with elagolix and for 1 week after discontinuing elagolix.eltrombopagMonitor Closely (1)ethinylestradiol will increase the level or effect of eltrombopag by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.elvitegravirSerious - Use Alternative (1)elvitegravir will decrease the level or effect of ethinylestradiol by unknown mechanism. Avoid or Use Alternate Drug. Consider alternative nonhormonal methods of contraception to add or replace combination oral contraceptiveelvitegravir/cobicistat/emtricitabine/tenofovir DFMonitor Closely (1)elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP3A4 inhibitor; contraindicated with CYP3A4 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.enasidenibMinor (2)enasidenib, levonorgestrel oral. unknown mechanism. Minor/Significance Unknown. Coadministration of enasidenib may increase or decrease the concentrations of combined hormonal contraceptives. Clinical significance of this interaction is unknown. enasidenib, ethinylestradiol. unknown mechanism. Minor/Significance Unknown. Coadministration of enasidenib may increase or decrease the concentrations of combined hormonal contraceptives. Clinical significance of this interaction is unknown.encorafenibMonitor Closely (2)encorafenib, levonorgestrel oral. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Encorafenib both inhibits and induces CYP3A4 at clinically relevant plasma concentrations. Coadministration of encorafenib with sensitive CYP3A4 substrates may result in increased toxicity or decreased efficacy of these agents. encorafenib will increase the level or effect of ethinylestradiol by Other (see comment). Modify Therapy/Monitor Closely. Encorafenib (a BCRP inhibitor) may increase the concentration and toxicities of BCRP substrates. Closely monitor for signs and symptoms of increased exposure and consider adjusting the dose of these substrates.Serious - Use Alternative (1)encorafenib will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of encorafenib with hormonal contraceptives (CYP3A4 substrates) can result in decreased concentrations and loss of hormonal contraceptive efficacy. Since encorafenib can cause fetal harm, advise women of childbearing potential to use a highly effective nonhormonal contraceptive during treatment and for 2 weeks after final encorafenib dose.enoxaparinSerious - Use Alternative (2)levonorgestrel oral, enoxaparin. Either decreases effects of the other by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Risk of thromboembolic disorders. ethinylestradiol decreases effects of enoxaparin by pharmacodynamic antagonism. Contraindicated. Risk of thromboembolic disorders.enzalutamideMonitor Closely (1)enzalutamide decreases levels of levonorgestrel oral by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)enzalutamide will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.eplerenoneMinor (1)ethinylestradiol will increase the level or effect of eplerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.erythromycin baseMonitor Closely (1)erythromycin base will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor. Antibiotics may decrease hormonal contraceptive efficacy.erythromycin ethylsuccinateMonitor Closely (1)erythromycin ethylsuccinate will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor. Antibiotics may decrease hormonal contraceptive efficacy.erythromycin lactobionateMonitor Closely (1)erythromycin lactobionate will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor. Antibiotics may decrease hormonal contraceptive efficacy.erythromycin stearateMonitor Closely (1)erythromycin stearate will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor. Antibiotics may decrease hormonal contraceptive efficacy.eslicarbazepine acetateSerious - Use Alternative (2)eslicarbazepine acetate will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Use additional or alternative nonhormonal birth control. eslicarbazepine acetate will decrease the level or effect of levonorgestrel oral by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Use additional or alternative nonhormonal birth control.etravirineMonitor Closely (2)etravirine will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended. etravirine decreases levels of levonorgestrel oral by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.exemestaneSerious - Use Alternative (1)ethinylestradiol decreases effects of exemestane by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Exemestane should not be given concurrently with any estrogens or estrogen-containing products.exenatide injectable solutionMonitor Closely (2)levonorgestrel oral, exenatide injectable solution. Other (see comment). Use Caution/Monitor. Comment: Oral contraceptives may decrease hypoglycemic effects of antidiabetics by impairing glucose tolerance. The effect of