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 stearateerythromycin 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.etravirineetravirine 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.exenatide injectable solutionethinylestradiol, 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 suspensionethinylestradiol, 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.fedratinibfedratinib 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.finerenoneethinylestradiol 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.flibanserinethinylestradiol 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.fluconazolefluconazole will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.fluvoxamineethinylestradiol will increase the level or effect of fluvoxamine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.fostemsavirfostemsavir 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.gemifloxacingemifloxacin 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.grapefruitgrapefruit will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.green teaethinylestradiol increases levels of green tea by decreasing elimination. Use Caution/Monitor.heminethinylestradiol decreases effects of hemin by pharmacodynamic antagonism. Use Caution/Monitor. Drugs that increase delta-aminolevulinic acid synthetase may decrease hemin effect.hyaluronidaseethinylestradiol 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.iloperidoneiloperidone 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.insulin aspartethinylestradiol 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 degludecethinylestradiol decreases effects of insulin degludec by pharmacodynamic antagonism. Use Caution/Monitor. Estrogens may impair glucose tolerance.insulin degludec/insulin aspartethinylestradiol decreases effects of insulin degludec/insulin aspart by pharmacodynamic antagonism. Use Caution/Monitor. Estrogens may impair glucose tolerance.insulin detemirethinylestradiol 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 glargineethinylestradiol 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 glulisineethinylestradiol 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 inhaledethinylestradiol decreases effects of insulin inhaled by pharmacodynamic antagonism. Use Caution/Monitor. Estrogens may impair glucose tolerance.insulin lisproethinylestradiol 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 NPHethinylestradiol 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 humanethinylestradiol 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 sulfateethinylestradiol will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.istradefyllineistradefylline 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.itraconazoleitraconazole 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.ketoconazoleketoconazole 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.lamotrigineethinylestradiol 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.lapatinibethinylestradiol will increase the level or effect of lapatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.lemborexantethinylestradiol 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.lenacapavirlenacapavir 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.levofloxacinlevofloxacin 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.levoketoconazolelevoketoconazole 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.liraglutideethinylestradiol decreases effects of liraglutide 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.lixisenatide (DSC)lixisenatide (DSC) will decrease the level or effect of ethinylestradiol by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. GLP1 agonists delay gastric emptying, which may affect absorption of concomitantly administered oral medications. Oral contraceptives should be taken at least 1 hr before lixisenatide administration or 11 hr after lixisenatide.lomitapideethinylestradiol increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lomitapide dose should not exceed 30 mg/day.lonapegsomatropinethinylestradiol will decrease the level or effect of lonapegsomatropin by Other (see comment). Use Caution/Monitor. Oral estrogens may reduce serum insulin-like growth factor-1 response to lonapegsomatropin. Patients receiving oral estrogen replacement may require higher lonapegsomatropin dosages.ethinylestradiol will decrease the level or effect of lonapegsomatropin by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Oral estrogens may reduce serum insulin-like growth factor I (IGF-1) response to growth hormone (GH) analogs. Higher GH dose may be requiredlorlatiniblorlatinib will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.lumefantrinelumefantrine will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.metforminethinylestradiol decreases effects of metformin by pharmacodynamic antagonism. Use Caution/Monitor.metronidazolemetronidazole 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.mexiletineethinylestradiol will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.midazolamethinylestradiol will increase the level or effect of midazolam 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.midazolam intranasalethinylestradiol will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of mild CYP3A4 inhibitors with midazolam intranasal may cause higher midazolam systemic exposure, which may prolong sedation.mifepristonemifepristone decreases effects of ethinylestradiol by pharmacodynamic antagonism. Use Caution/Monitor. Backup contraceptive method recommended.minocyclineminocycline 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.mitotanemitotane decreases levels of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Mitotane is a strong inducer of cytochrome P-4503A4; monitor when coadministered with CYP3A4 substrates for possible dosage adjustments.moxifloxacinmoxifloxacin 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.nafcillinnafcillin will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.neomycin POneomycin PO 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.nicardipineethinylestradiol will increase the level or effect of nicardipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.nilotinibethinylestradiol will increase the level or effect of nilotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.nirmatrelvirnirmatrelvir will decrease the level or effect of ethinylestradiol by increasing metabolism. Modify Therapy/Monitor Closely. Consider using additional nonhormonal contraceptive method for remainder of cycle. Mechanism unknown, but possibly by ritonavir CYP2C9 or CYP1A2 induction.nirmatrelvir/ritonavirnirmatrelvir/ritonavir will decrease the level or effect of ethinylestradiol by increasing metabolism. Modify Therapy/Monitor Closely. Consider using additional nonhormonal contraceptive method for remainder of cycle. Mechanism unknown, but possibly by ritonavir CYP2C9 or CYP1A2 induction.nitrofurantoinnitrofurantoin 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.ofloxacinofloxacin 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.olanzapineethinylestradiol will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.oteseconazoleoteseconazole will increase the level or effect of ethinylestradiol by Other (see comment). Modify Therapy/Monitor Closely. Otesezonale, a BCRP inhibitor, may increase the effects and risk of toxicities of BCRP substrates. Use lowest starting dose of BCRP substrate, or consider reducing BCRP substrate dose.paromomycinparomomycin 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.penicillin G aqueouspenicillin G aqueous decreases levels of ethinylestradiol by increasing metabolism. Use Caution/Monitor. Risk of oral contraceptive failure.penicillin VKpenicillin VK 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.pioglitazonepioglitazone decreases levels of ethinylestradiol by unknown mechanism. Use Caution/Monitor.posaconazoleposaconazole will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.quinupristin/dalfopristinquinupristin/dalfopristin will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.ramelteonethinylestradiol will increase the level or effect of ramelteon by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.rasagilineethinylestradiol will increase the level or effect of rasagiline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Recommended dose of rasagiline is 0.5mg daily in combination with CYP1A2 inhibitors.ribociclibribociclib will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.romidepsinromidepsin decreases effects of ethinylestradiol by receptor binding competition. Use Caution/Monitor.ropiniroleethinylestradiol will increase the level or effect of ropinirole by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.ethinylestradiol increases levels of ropinirole by unspecified interaction mechanism. Use Caution/Monitor.rucaparibrucaparib will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP3A4 substrates, if clinically indicated.rufinamiderufinamide decreases effects of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Rufinamide is a weak inducer of the CYP 3A4 enzyme and can decrease exposure of drugs that are substrates of CYP3A4. .selegilineethinylestradiol increases levels of selegiline by Other (see comment). Use Caution/Monitor. Comment: Oral contraceptives inhibit the N demethylatin of selegiline.selegiline transdermalethinylestradiol increases levels of selegiline transdermal by Other (see comment). Use