of contraceptive failure. Use Caution/Monitor. Antibiotics may decrease hormonal contraceptive efficacy.clarithromycinMonitor Closely (2)clarithromycin will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate 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. clarithromycin will increase the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with CYP3A4 inhibitors may increase the plasma hormone concentrations. Use of a nonhormonal contraceptive is recommended.clindamycinMonitor Closely (1)clindamycin will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate 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.clonazepamMonitor Closely (1)levonorgestrel oral/ethinylestradiol/ferrous bisglycinate will increase the level or effect of clonazepam by decreasing metabolism. Use Caution/Monitor. Ethinyl estradiol may inhibit the clearance of benzodiazepines that undergo oxidation, thereby increasing serum concentrations of concomitantly administered benzodiazepines.cobicistatMonitor Closely (1)cobicistat will increase the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with CYP3A4 inhibitors may increase the plasma hormone concentrations. Use of a nonhormonal contraceptive is recommended.colesevelamMonitor Closely (1)colesevelam decreases levels of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by Other (see comment). Modify Therapy/Monitor Closely. Comment: Colesevelam, a bile acid sequestrant, given together with a combined hormonal contraceptives (CHCs), has been shown to significantly decrease the AUC of ethinyl estradiol (EE). Oral contraceptives containing ethinyl estradiol should be administered at least 4 hours before the colesevelam dose.conivaptanMonitor Closely (1)conivaptan will increase the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with CYP3A4 inhibitors may increase the plasma hormone concentrations. Use of a nonhormonal contraceptive is recommended.cyclosporineMonitor Closely (1)levonorgestrel oral/ethinylestradiol/ferrous bisglycinate, 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 (1)dabrafenib will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. The efficacy of hormonal contraceptives may be reduced. Use an alternative method of contraception or a backup method when enzyme inducers are used with combined hormonal contraceptives (CHCs), and continue backup contraception for 28 days after discontinuing enzyme inducer to ensure contraceptive reliability.darunavirSerious - Use Alternative (1)darunavir, levonorgestrel oral/ethinylestradiol/ferrous bisglycinate. 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.demeclocyclineMonitor Closely (1)demeclocycline will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate 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.dexamethasoneMonitor Closely (1)dexamethasone will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. The efficacy of hormonal contraceptives may be reduced. Use an alternative method of contraception or a backup method when enzyme inducers are used with combined hormonal contraceptives (CHCs), and continue backup contraception for 28 days after discontinuing enzyme inducer to ensure contraceptive reliability.diazepamMonitor Closely (1)levonorgestrel oral/ethinylestradiol/ferrous bisglycinate will increase the level or effect of diazepam by 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 levonorgestrel oral/ethinylestradiol/ferrous bisglycinate 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.doxycyclineMonitor Closely (1)doxycycline will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate 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.efavirenzMonitor Closely (1)efavirenz will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. The efficacy of hormonal contraceptives may be reduced. Use an alternative method of contraception or a backup method when enzyme inducers are used with combined hormonal contraceptives (CHCs), and continue backup contraception for 28 days after discontinuing enzyme inducer to ensure contraceptive reliability.elagolixSerious - Use Alternative (1)levonorgestrel oral/ethinylestradiol/ferrous bisglycinate 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.enasidenibMinor (1)enasidenib, levonorgestrel oral/ethinylestradiol/ferrous bisglycinate. 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.encorafenibSerious - Use Alternative (1)encorafenib will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate 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. 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.enzalutamideMonitor Closely (1)enzalutamide will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. The efficacy of hormonal contraceptives may be reduced. Use an alternative method of contraception or a backup method when enzyme inducers are used with combined hormonal contraceptives (CHCs), and continue backup contraception for 28 days after discontinuing enzyme inducer to ensure contraceptive reliability.erythromycin baseMonitor Closely (1)erythromycin base will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate 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 levonorgestrel oral/ethinylestradiol/ferrous bisglycinate 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 levonorgestrel oral/ethinylestradiol/ferrous bisglycinate 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 levonorgestrel oral/ethinylestradiol/ferrous bisglycinate 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 acetateMonitor Closely (1)eslicarbazepine acetate will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. The efficacy of hormonal contraceptives may be reduced. Use an alternative method of contraception or a backup method when enzyme inducers are used with combined hormonal contraceptives (CHCs), and continue backup contraception for 28 days after discontinuing enzyme inducer to ensure contraceptive reliability.etravirineMonitor Closely (1)etravirine will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. The efficacy of hormonal contraceptives may be reduced. Use an alternative method of contraception or a backup method when enzyme inducers are used with combined hormonal contraceptives (CHCs), and continue backup contraception for 28 days after discontinuing enzyme inducer to ensure contraceptive reliability.fosamprenavirMonitor Closely (1)fosamprenavir will increase the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with CYP3A4 inhibitors may increase the plasma hormone concentrations. Use of a nonhormonal contraceptive is recommended.fosaprepitantMonitor Closely (1)fosaprepitant will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. The efficacy of hormonal contraceptives may be reduced. Use an alternative method of contraception or a backup method when enzyme inducers are used with combined hormonal contraceptives (CHCs), and continue backup contraception for 28 days after discontinuing enzyme inducer to ensure contraceptive reliability.fosphenytoinMonitor Closely (1)fosphenytoin will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. The efficacy of hormonal contraceptives may be reduced. Use an alternative method of contraception or a backup method when enzyme inducers are used with combined hormonal contraceptives (CHCs), and continue backup contraception for 28 days after discontinuing enzyme inducer to ensure contraceptive reliability.gemifloxacinMonitor Closely (1)gemifloxacin will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate 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.grapefruitMonitor Closely (1)grapefruit will increase the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with CYP3A4 inhibitors may increase the plasma hormone concentrations. Use of a nonhormonal contraceptive is recommended.griseofulvinMonitor Closely (1)griseofulvin will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. The efficacy of hormonal contraceptives may be reduced. Use an alternative method of contraception or a backup method when enzyme inducers are used with combined hormonal contraceptives (CHCs), and continue backup contraception for 28 days after discontinuing enzyme inducer to ensure contraceptive reliability.idelalisibMonitor Closely (1)idelalisib will increase the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with CYP3A4 inhibitors may increase the plasma hormone concentrations. Use of a nonhormonal contraceptive is recommended.imatinibMonitor Closely (1)imatinib will increase the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with CYP3A4 inhibitors may increase the plasma hormone concentrations. Use of a nonhormonal contraceptive is recommended.indinavirSerious - Use Alternative (1)indinavir, levonorgestrel oral/ethinylestradiol/ferrous bisglycinate. 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.isavuconazonium sulfateSerious - Use Alternative (1)isavuconazonium sulfate will increase the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.isoniazidMonitor Closely (1)isoniazid will increase the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with CYP3A4 inhibitors may increase the plasma hormone concentrations. Use of a nonhormonal contraceptive is recommended.itraconazoleMonitor Closely (1)itraconazole will increase the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with CYP3A4 inhibitors may increase the plasma hormone concentrations. Use of a nonhormonal contraceptive is recommended.ivosidenibMonitor Closely (1)ivosidenib will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by unspecified interaction mechanism. Modify Therapy/Monitor Closely. Coadministration of ivosidenib may decrease the concentrations of hormonal contraceptives, consider alternative methods of contraception in patients receiving ivosidenib. ketoconazoleMonitor Closely (1)ketoconazole will increase the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with CYP3A4 inhibitors may increase the plasma hormone concentrations. Use of a nonhormonal contraceptive is recommended.lamotrigineMonitor Closely (1)levonorgestrel oral/ethinylestradiol/ferrous bisglycinate decreases levels of lamotrigine by unspecified interaction mechanism. Use Caution/Monitor. Significant decrease in plasma concentration of lamotrigine when concomitantly used with combined hormonal contraceptives (CHCs) containing EE, likely due to induction of lamotrigine glucuronidation. This may reduce seizure control; therefore, dosage adjustments of lamotrigine may be necessary.lesinuradMonitor Closely (1)lesinurad will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. The efficacy of hormonal contraceptives may be reduced. Use an alternative method of contraception or a backup method when enzyme inducers are used with combined hormonal contraceptives (CHCs), and continue backup contraception for 28 days after discontinuing enzyme inducer to ensure contraceptive reliability.levofloxacinMonitor Closely (1)levofloxacin will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate 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.levoketoconazoleMonitor Closely (1)levoketoconazole will increase the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with CYP3A4 inhibitors may increase the plasma hormone concentrations. Use of a nonhormonal contraceptive is recommended.levothyroxineMonitor Closely (1)levonorgestrel oral/ethinylestradiol/ferrous bisglycinate will decrease the level or effect of levothyroxine by unknown mechanism. Modify Therapy/Monitor Closely. The estrogen component of combined hormonal contraceptives (CHCs) may raise the serum concentrations of thyroxine-binding globulin. Women on thyroid hormone replacement therapy may need increased doses of thyroid hormone with use of CHCs.liothyronineMonitor Closely (1)levonorgestrel oral/ethinylestradiol/ferrous bisglycinate will decrease the level or effect of liothyronine by unknown