increase the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.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.Serious - Use Alternative (1)erythromycin stearate will increase the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.eslicarbazepine acetateMinor (1)eslicarbazepine acetate will decrease the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.Serious - Use Alternative (1)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.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 will decrease the level or effect of etonogestrel 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)etonogestrel decreases effects of exenatide injectable solution by pharmacodynamic antagonism. Use Caution/Monitor. Estrogens may decrease hypoglycemic effects of antidiabetics by impairing glucose tolerance. Monitor for glycemic control in diabetic patients. ethinylestradiol, 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 exenatide to slow gastric emptying may reduce the extent and rate of oral medications that require rapid GI absorption. Advise patients to take oral contraceptives at least 1 hr before exenatide. .exenatide injectable suspensionMonitor Closely (2)ethinylestradiol, exenatide injectable suspension. Other (see comment). Use Caution/Monitor. Comment: Oral contraceptives may decrease hypoglycemic effects of antidiabetics by impairing glucose tolerance. The effect of exenatide to slow gastric emptying may reduce the extent and rate of oral medications that require rapid GI absorption. Advise patients to take oral contraceptives at least 1 hr before exenatide. etonogestrel decreases effects of exenatide injectable suspension by pharmacodynamic antagonism. Use Caution/Monitor. Estrogens may decrease hypoglycemic effects of antidiabetics by impairing glucose tolerance. Monitor for glycemic control in diabetic patients.fedratinibMonitor Closely (1)fedratinib will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.Serious - Use Alternative (1)ethinylestradiol will increase the level or effect of fedratinib by Other (see comment). Avoid or Use Alternate Drug. Avoid coadministration of fedratinib (a CYP3A4 and CYP2C19 substrate) with dual CYP3A4 and CYP2C19 inhibitor. Effect of coadministration of a dual CYP3A4 and CYP2C19 inhibitor with fedratinib has not been studied.felbamateMinor (1)felbamate decreases levels of ethinylestradiol by unknown mechanism. Minor/Significance Unknown.fexinidazoleSerious - Use Alternative (1)fexinidazole will increase the level or effect of ethinylestradiol by affecting hepatic enzyme CYP2E1 metabolism. Avoid or Use Alternate Drug. Fexinidazole inhibits CYP3A4. Coadministration may increase risk for adverse effects of CYP3A4 substrates. fezolinetantContraindicated (1)ethinylestradiol will increase the level or effect of fezolinetant by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated. Fezolinetant AUC and peak plasma concentration are increased if coadministered with drugs that are weak, moderate, or strong CYP1A2 inhibitorsfinerenoneMonitor Closely (1)ethinylestradiol will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or weak CYP3A4 inhibitors. Adjust finererone dosage as needed.flibanserinMonitor Closely (1)ethinylestradiol will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Increased flibanserin adverse effects may occur if coadministered with multiple weak CYP3A4 inhibitors.fluconazoleMonitor Closely (2)fluconazole will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. fluconazole will increase the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fluvoxamineMonitor Closely (1)ethinylestradiol will increase the level or effect of fluvoxamine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.fosamprenavirMonitor Closely (1)fosamprenavir will increase the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)fosamprenavir, ethinylestradiol. unspecified interaction mechanism. Avoid or Use Alternate Drug. Coadministration may decrease amprenavir AUC, and may lead to loss of virologic response. Coadministration of fosamprenavir with ethinyl estradiol may alter hormone levels. Alternative methods of nonhormonal contraception are recommended.fosaprepitantMonitor Closely (1)fosaprepitant will increase the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fosphenytoinMonitor Closely (1)fosphenytoin will decrease the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fostemsavirMonitor Closely (1)fostemsavir will increase the level or effect of ethinylestradiol by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir. Do not ethinyl estradiol dose of exceed 30 mcg/day.frovatriptanMinor (1)ethinylestradiol will increase the level or effect of frovatriptan by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.gemifloxacinMonitor Closely (1)gemifloxacin 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.grapefruitMonitor Closely (2)grapefruit will increase the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. grapefruit will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.green teaMonitor Closely (1)ethinylestradiol increases levels of green tea by decreasing elimination. Use Caution/Monitor.griseofulvinMonitor Closely (1)griseofulvin will decrease the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)griseofulvin 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.heminMonitor Closely (1)ethinylestradiol decreases effects of hemin by pharmacodynamic antagonism. Use Caution/Monitor. Drugs that increase delta-aminolevulinic acid synthetase may decrease hemin effect.heparinSerious - Use Alternative (1)ethinylestradiol decreases effects of heparin by pharmacodynamic antagonism. Contraindicated. Risk of thromboembolic disorders.hyaluronidaseMonitor Closely (1)ethinylestradiol decreases effects of hyaluronidase by Other (see comment). Use Caution/Monitor. Comment: Estrogens, when given in large systemic doses, may render tissues partially resistant to the action of hyaluronidase. Patients may require larger amounts of hyaluronidase for equivalent dispersing effect.hydrocortisoneMonitor Closely (1)hydrocortisone will decrease the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.idelalisibSerious - Use Alternative (1)idelalisib will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substratesiloperidoneMonitor Closely (1)iloperidone increases levels of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Iloperidone is a time-dependent CYP3A inhibitor and may lead to increased plasma levels of drugs predominantly eliminated by CYP3A4.imipramineMinor (1)ethinylestradiol, imipramine. 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.indinavirMonitor Closely (1)indinavir will increase the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)indinavir, ethinylestradiol. Other (see comment). Avoid or Use Alternate Drug. Comment: 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. .insulin aspartMonitor Closely (1)ethinylestradiol decreases effects of insulin aspart by pharmacodynamic antagonism. Use Caution/Monitor. Oral contraceptives may decrease hypoglycemic effects of antidiabetics by impairing glucose tolerance. Monitor for glycemic control in diabetic patients.insulin degludecMonitor Closely (2)ethinylestradiol decreases effects of insulin degludec by pharmacodynamic antagonism. Use Caution/Monitor. Estrogens may impair glucose tolerance. etonogestrel decreases effects of insulin degludec by pharmacodynamic antagonism. Use Caution/Monitor. Progestins may impair glucose tolerance.insulin degludec/insulin aspartMonitor Closely (2)ethinylestradiol decreases effects of insulin degludec/insulin aspart by pharmacodynamic antagonism. Use Caution/Monitor. Estrogens may impair glucose tolerance. etonogestrel decreases effects of insulin degludec/insulin aspart by pharmacodynamic antagonism. Use Caution/Monitor. Progestins may impair glucose tolerance.insulin detemirMonitor Closely (1)ethinylestradiol decreases effects of insulin detemir by pharmacodynamic antagonism. Use Caution/Monitor. Oral contraceptives may decrease hypoglycemic effects of antidiabetics by impairing glucose tolerance. Monitor for glycemic control in diabetic patients.insulin glargineMonitor Closely (1)ethinylestradiol decreases effects of insulin glargine by pharmacodynamic antagonism. Use Caution/Monitor. Oral contraceptives may decrease hypoglycemic effects of antidiabetics by impairing glucose tolerance. Monitor for glycemic control in diabetic patients.insulin glulisineMonitor Closely (1)ethinylestradiol decreases effects of insulin glulisine by pharmacodynamic antagonism. Use Caution/Monitor. Oral contraceptives may decrease hypoglycemic effects of antidiabetics by impairing glucose tolerance. Monitor for glycemic control in diabetic patients.insulin inhaledMonitor Closely (2)etonogestrel decreases effects of insulin inhaled by pharmacodynamic antagonism. Use Caution/Monitor. Progestins may impair glucose tolerance. ethinylestradiol decreases effects of insulin inhaled by pharmacodynamic antagonism. Use Caution/Monitor. Estrogens may impair glucose tolerance.insulin lisproMonitor Closely (1)ethinylestradiol decreases effects of insulin lispro by pharmacodynamic antagonism. Use Caution/Monitor. Oral contraceptives may decrease hypoglycemic effects of antidiabetics by impairing glucose tolerance. Monitor for glycemic control in diabetic patients.insulin NPHMonitor Closely (1)ethinylestradiol decreases effects of insulin NPH by pharmacodynamic antagonism. Use Caution/Monitor. Oral contraceptives may decrease hypoglycemic effects of antidiabetics by impairing glucose tolerance. Monitor for glycemic control in diabetic patients.insulin regular humanMonitor Closely (1)ethinylestradiol decreases effects of insulin regular human by pharmacodynamic antagonism. Use Caution/Monitor. Oral contraceptives may decrease hypoglycemic effects of antidiabetics by impairing glucose tolerance. Monitor for glycemic control in diabetic patients.isavuconazonium sulfateMonitor Closely (1)ethinylestradiol will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)isavuconazonium sulfate will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.isoniazidMonitor Closely (1)isoniazid will increase the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.istradefyllineMonitor Closely (1)istradefylline will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of CYP3A4 substrates in clinical trials. This effect was not observed with istradefylline 20 mg/day. Consider dose reduction of sensitive CYP3A4 substrates.itraconazoleMonitor Closely (2)itraconazole will increase the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. itraconazole will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibitors such as itraconazole may increase plasma hormone levels.ivosidenibSerious - Use Alternative (1)ivosidenib will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP3A4 substrates with ivosidenib or replace with alternate therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs.ketoconazoleMonitor Closely (2)ketoconazole will increase the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. ketoconazole will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibitors such as ketoconazole may increase plasma hormone levels.lamotrigineMonitor Closely (2)etonogestrel will decrease the level or effect of lamotrigine by increasing hepatic clearance. Use Caution/Monitor. Combination oral contraceptives have been shown to significantly decrease plasma concentrations of lamotrigine, likely due to induction of lamotrigine glucuronidation. ethinylestradiol decreases levels of lamotrigine by increasing hepatic clearance. Use Caution/Monitor. Combination oral contraceptives have been shown to significantly decrease plasma concentrations of lamotrigine, likely due to induction of lamotrigine glucuronidation.lapatinibMonitor Closely (2)ethinylestradiol will increase the level or effect of lapatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. lapatinib will increase the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.larotrectinibMinor (1)larotrectinib will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.lemborexantMonitor Closely (1)ethinylestradiol will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Lower nightly dose of lemborexant recommended if coadministered with weak CYP3A4 inhibitors. See drug monograph for specific dosage modification.lenacapavirMonitor Closely (1)lenacapavir will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lencapavir (a moderate CYP3A4 inhibitor) may increase CYP3A4 substrates initiated within 9 months after last SC dose of lenacapavir, which may increase potential risk of adverse reactions of CYP3A4 substrates.leniolisibSerious - Use Alternative (1)leniolisib will increase the level or effect of ethinylestradiol by Other (see comment). Avoid or Use Alternate Drug. Leniolisib, a BCRP inhibitor, may increase systemic exposure of BCRP substrateslesinuradSerious - Use Alternative (2)lesinurad decreases effects of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate