is a strong inducer of cytochrome P-4503A4; monitor when coadministered with CYP3A4 substrates for possible dosage adjustments.moxifloxacinMonitor Closely (1)moxifloxacin will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.mycophenolateMinor (1)mycophenolate decreases effects of estrogens conjugated synthetic by unknown mechanism. Minor/Significance Unknown. Clinical significance unclear.nafcillinMonitor Closely (2)nafcillin will decrease the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. nafcillin will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.nefazodoneMonitor Closely (1)nefazodone will increase the level or effect of estrogens conjugated synthetic by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)nefazodone will increase the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.nelfinavirMonitor Closely (1)nelfinavir will increase the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.neomycin POMonitor Closely (1)neomycin PO will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.nevirapineMonitor Closely (1)nevirapine will decrease the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.nicardipineMonitor Closely (1)nicardipine will increase the level or effect of estrogens conjugated synthetic by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.nifedipineMonitor Closely (2)nifedipine will increase the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. nifedipine will decrease the level or effect of estrogens conjugated synthetic by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.nilotinibMonitor Closely (2)nilotinib will increase the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. nilotinib will increase the level or effect of estrogens conjugated synthetic by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.nitrofurantoinMonitor Closely (1)nitrofurantoin will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.nortriptylineMinor (1)estrogens conjugated synthetic, nortriptyline. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Estrogens and progestins may decr tricyclic antidepressant effects, while increasing TCA plasma concentration and adverse effects.ofloxacinMonitor Closely (1)ofloxacin will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.ospemifeneContraindicated (1)ospemifene, estrogens conjugated synthetic. Either increases effects of the other by pharmacodynamic synergism. Contraindicated.oxcarbazepineMonitor Closely (1)oxcarbazepine will decrease the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.oxytetracyclineMonitor Closely (1)oxytetracycline will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.pacritinibSerious - Use Alternative (1)estrogens conjugated synthetic will decrease the level or effect of pacritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.paromomycinMonitor Closely (1)paromomycin will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.pentobarbitalMonitor Closely (1)pentobarbital will decrease the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.phenindioneSerious - Use Alternative (1)estrogens conjugated synthetic decreases effects of phenindione by pharmacodynamic antagonism. Contraindicated. Risk of thromboembolic disorders.phenobarbitalMonitor Closely (2)phenobarbital will decrease the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. phenobarbital will decrease the level or effect of estrogens conjugated synthetic by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.phenytoinMonitor Closely (2)phenytoin will decrease the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. phenytoin will decrease the level or effect of estrogens conjugated synthetic by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. If the estrogen is being used for contraception then loss of contraception may occur. phytoestrogensMinor (1)phytoestrogens decreases effects of estrogens conjugated synthetic by pharmacodynamic antagonism. Minor/Significance Unknown.pivmecillinamMonitor Closely (1)pivmecillinam will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.pleurisy rootMinor (1)pleurisy root decreases effects of estrogens conjugated synthetic by unspecified interaction mechanism. Minor/Significance Unknown. Theoretical interaction.posaconazoleMonitor Closely (1)posaconazole will increase the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.prednisoneMonitor Closely (1)prednisone will decrease the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.primidoneMonitor Closely (1)primidone will decrease the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.protamineSerious - Use Alternative (1)estrogens conjugated synthetic decreases effects of protamine by pharmacodynamic antagonism. Contraindicated. Risk of thromboembolic disorders.protriptylineMinor (1)estrogens conjugated synthetic, protriptyline. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Estrogens and progestins may decr tricyclic antidepressant effects, while increasing TCA plasma concentration and adverse effects.pyridoxineMinor (1)estrogens conjugated synthetic decreases levels of pyridoxine by altering metabolism. Minor/Significance Unknown.pyridoxine (Antidote)Minor (1)estrogens conjugated synthetic decreases levels of pyridoxine (Antidote) by altering metabolism. Minor/Significance Unknown.quercetinMonitor Closely (1)quercetin will decrease the level or effect of estrogens conjugated synthetic by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.quinidineSerious - Use Alternative (1)quinidine will increase the level or effect of estrogens conjugated synthetic by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.quinupristin/dalfopristinMonitor Closely (2)quinupristin/dalfopristin will increase the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. quinupristin/dalfopristin will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.ranolazineMonitor Closely (1)ranolazine will increase the level or effect of estrogens conjugated synthetic by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.ribociclibMonitor Closely (1)ribociclib will increase the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.rifabutinSerious - Use Alternative (1)rifabutin will decrease the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.rifampinMonitor Closely (1)rifampin will decrease the level or effect of estrogens conjugated synthetic by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.rifapentineMonitor Closely (1)rifapentine will decrease the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.ritonavirMonitor Closely (2)ritonavir will increase the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. ritonavir will increase the level or effect of estrogens conjugated synthetic by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.ropiniroleMinor (1)estrogens conjugated synthetic increases levels of ropinirole by unspecified interaction mechanism. Minor/Significance Unknown.rose hipsMinor (1)estrogens conjugated synthetic decreases levels of rose hips by increasing elimination. Minor/Significance Unknown.roxithromycinMonitor Closely (1)roxithromycin will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Modify Therapy/Monitor Closely.rufinamideMonitor Closely (1)rufinamide will decrease the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.secobarbitalMonitor Closely (1)secobarbital will decrease the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.sirolimusMonitor Closely (1)sirolimus will increase the level or effect of estrogens conjugated synthetic by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.somapacitanMonitor Closely (1)estrogens conjugated synthetic decreases effects of somapacitan by Other (see comment). Modify Therapy/Monitor Closely. Comment: Oral estrogens may reduce the serum IGF-1 response to somapacitan. Patients may require higher somapacitan dosages. See drug monograph for starting dose recommendations.St John's WortMonitor Closely (1)St John's Wort will decrease the level or effect of estrogens conjugated synthetic by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)St John's Wort will decrease the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.stiripentolMonitor Closely (1)stiripentol, estrogens conjugated synthetic. affecting hepatic enzyme CYP1A2 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP1A2 inhibitor and inducer. Monitor CYP1A2 substrates coadministered with stiripentol for increased or decreased effects. CYP1A2 substrates may require dosage adjustment.streptomycinMonitor Closely (1)streptomycin will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.sulfadiazineMonitor Closely (1)sulfadiazine will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.sulfamethoxazoleMonitor Closely (1)sulfamethoxazole will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.sulfisoxazoleMonitor Closely (1)sulfisoxazole will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.tacrolimusMonitor Closely (1)tacrolimus will increase the level or effect of estrogens conjugated synthetic by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.tazemetostatMonitor Closely (2)tazemetostat will decrease the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. estrogens conjugated synthetic will decrease the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.tecovirimatMonitor Closely (1)tecovirimat will decrease the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.teicoplaninMonitor Closely (1)teicoplanin will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.temocillinMonitor Closely (1)temocillin will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.teriflunomideMonitor Closely (1)teriflunomide decreases levels of estrogens conjugated synthetic by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.tetracyclineMonitor Closely (1)tetracycline will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.ticarcillinMonitor Closely (1)ticarcillin will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.tigecyclineMonitor Closely (1)tigecycline will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.tobramycinMonitor Closely (1)tobramycin will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.tolvaptanMonitor Closely (1)tolvaptan will increase the level or effect of estrogens conjugated synthetic by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.topiramateMonitor Closely (1)topiramate will decrease the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.trazodoneMonitor Closely (1)trazodone will decrease the level or effect of estrogens conjugated synthetic by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Minor (1)estrogens conjugated synthetic, trazodone. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Estrogens and progestins may decr tricyclic antidepressant effects, while increasing TCA plasma concentration and adverse effects.trimethoprimMonitor Closely (1)trimethoprim will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.trimipramineMinor (1)estrogens conjugated synthetic, trimipramine. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Estrogens and progestins may decr tricyclic antidepressant effects, while increasing TCA plasma concentration and adverse effects.tucatinibSerious - Use Alternative (1)tucatinib will increase the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of tucatinib with CYP3A substrates, where minimal concentration changes may lead to serious or life-threatening toxicities. If unavoidable, reduce CYP3A substrate dose according to product labeling.ubrogepantMonitor Closely (1)estrogens conjugated synthetic will decrease the level or effect of ubrogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Dose adjustment is recommended with concomitant use of ubrogepant and moderate and weak CYP3A4 inducers. (see Dosage Modifications)vancomycinMonitor Closely (1)vancomycin will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.verapamilMonitor Closely (2)verapamil will increase the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. verapamil will increase the level or effect of estrogens conjugated synthetic