then loss of contraception may occur. pivmecillinampivmecillinam will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.posaconazoleposaconazole will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.prednisoneprednisone will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.primidoneprimidone will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.quercetinquercetin will decrease the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.quinupristin/dalfopristinquinupristin/dalfopristin will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.quinupristin/dalfopristin will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.ranolazineranolazine will increase the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.ribociclibribociclib will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.rifampinrifampin will decrease the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.rifapentinerifapentine will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.ritonavirritonavir will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.ritonavir will increase the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.roxithromycinroxithromycin will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Modify Therapy/Monitor Closely.rufinamiderufinamide will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.saquinavirsaquinavir will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.secobarbitalsecobarbital will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.simvastatinsimvastatin will increase the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.sirolimussirolimus will increase the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.somapacitanconjugated estrogens 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 WortSt John's Wort will decrease the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.stiripentolstiripentol, conjugated estrogens. 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.streptomycinstreptomycin will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.sulfadiazinesulfadiazine will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.sulfamethoxazolesulfamethoxazole will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.sulfisoxazolesulfisoxazole will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.tacrolimustacrolimus will increase the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.tazemetostatconjugated estrogens will decrease the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.tecovirimattecovirimat will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.teicoplaninteicoplanin will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.temocillintemocillin will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.tenapanortenapanor decreases levels of conjugated estrogens by Other (see comment). Use Caution/Monitor. Comment: Tenapanor (an inhibitor of intestinal uptake transporter, OATP2B1) may reduce the exposure of OATP2B1 substrates.teniposideteniposide will increase the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.tesamorelintesamorelin will decrease the level or effect of conjugated estrogens by altering metabolism. Use Caution/Monitor. May decrease efficacy; monitortetracyclinetetracycline will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.ticarcillinticarcillin will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.tigecyclinetigecycline will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.tobramycintobramycin will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.tolvaptantolvaptan will increase the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.topiramatetopiramate will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.trazodonetrazodone will decrease the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.trimethoprimtrimethoprim will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.ubrogepantconjugated estrogens 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)valproic acidconjugated estrogens will decrease the level or effect of valproic acid by increasing elimination. Modify Therapy/Monitor Closely. May lead to increased seizure frequencyvancomycinvancomycin will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.verapamilverapamil will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.verapamil will increase the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.voriconazolevoriconazole will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.zafirlukastzafirlukast will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (39)acetazolamideacetazolamide will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.amitriptylineconjugated estrogens, amitriptyline. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Estrogens and progestins may decr tricyclic antidepressant effects, while increasing TCA plasma concentration and adverse effects.amoxapineconjugated estrogens, amoxapine. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Estrogens and progestins may decr tricyclic antidepressant effects, while increasing TCA plasma concentration and adverse effects.anastrozoleanastrozole will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.androstenedioneandrostenedione increases effects of conjugated estrogens by pharmacodynamic synergism. Minor/Significance Unknown.ascorbic acidconjugated estrogens decreases levels of ascorbic acid by increasing elimination. Minor/Significance Unknown.boronboron increases levels of conjugated estrogens by altering metabolism. Minor/Significance Unknown.clomipramineconjugated estrogens, clomipramine. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Estrogens and progestins may decr tricyclic antidepressant effects, while increasing TCA plasma concentration and adverse effects.cyanocobalaminconjugated estrogens decreases levels of cyanocobalamin by altering metabolism. Minor/Significance Unknown.cyclophosphamidecyclophosphamide will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.desipramineconjugated estrogens, desipramine. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Estrogens and progestins may decr tricyclic antidepressant effects, while increasing TCA plasma concentration and adverse effects.dosulepinconjugated estrogens, dosulepin. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Estrogens and progestins may decr tricyclic antidepressant effects, while increasing TCA plasma concentration and adverse effects.doxepinconjugated estrogens, doxepin. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Estrogens and progestins may decr tricyclic antidepressant effects, while increasing TCA plasma concentration and adverse effects.exemestaneconjugated estrogens decreases levels of exemestane by increasing metabolism. Minor/Significance Unknown.folic acidconjugated estrogens decreases levels of folic acid by altering metabolism. Minor/Significance Unknown.imipramineconjugated estrogens, imipramine. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Estrogens and progestins may decr tricyclic antidepressant effects, while increasing TCA plasma concentration and adverse effects.isoniazidisoniazid will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.L-methylfolateconjugated estrogens decreases levels of L-methylfolate by altering metabolism. Minor/Significance Unknown.larotrectiniblarotrectinib will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.lofepramineconjugated estrogens, lofepramine. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Estrogens and progestins may decr tricyclic antidepressant effects, while increasing TCA plasma concentration and adverse effects.magnesium chlorideconjugated estrogens decreases levels of magnesium chloride by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.magnesium citrateconjugated estrogens decreases levels of magnesium citrate by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.magnesium hydroxideconjugated estrogens decreases levels of magnesium hydroxide by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.magnesium oxideconjugated estrogens decreases levels of magnesium oxide by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.magnesium sulfateconjugated estrogens decreases levels of magnesium sulfate by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.maprotilineconjugated estrogens, maprotiline. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Estrogens and progestins may decr tricyclic antidepressant effects, while increasing TCA plasma concentration and adverse effects.metyraponeconjugated estrogens decreases effects of metyrapone by unspecified interaction mechanism. Minor/Significance Unknown.mycophenolatemycophenolate decreases effects of conjugated estrogens by unknown mechanism. Minor/Significance Unknown. Clinical significance unclear.nortriptylineconjugated estrogens, nortriptyline. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Estrogens and progestins may decr tricyclic antidepressant effects, while increasing TCA plasma concentration and adverse effects.phytoestrogensphytoestrogens decreases effects of conjugated estrogens by pharmacodynamic antagonism. Minor/Significance Unknown.pleurisy rootpleurisy root decreases effects of conjugated estrogens by unspecified interaction mechanism. Minor/Significance Unknown. Theoretical interaction.progesterone, naturalprogesterone, natural, conjugated estrogens. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Combination may produce breast tenderness.protriptylineconjugated estrogens, protriptyline. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Estrogens and progestins may decr tricyclic antidepressant effects, while increasing TCA plasma concentration and adverse effects.pyridoxineconjugated estrogens decreases levels of pyridoxine by altering metabolism. Minor/Significance Unknown.pyridoxine (Antidote)conjugated estrogens decreases levels of pyridoxine (Antidote) by altering metabolism. Minor/Significance Unknown.ropiniroleconjugated estrogens increases levels of ropinirole by unspecified interaction mechanism. Minor/Significance Unknown.rose hipsconjugated estrogens decreases levels of rose hips by increasing elimination. Minor/Significance Unknown.trazodoneconjugated estrogens, trazodone. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Estrogens and progestins may decr tricyclic antidepressant effects, while increasing TCA plasma concentration and adverse effects.trimipramineconjugated estrogens, trimipramine. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Estrogens and progestins may decr tricyclic antidepressant effects, while increasing TCA plasma concentration and adverse effects.abametapirSerious - Use Alternative (2)abametapir will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP3A4 substrates. If not feasible, avoid use of abametapir. abametapir will increase the level or effect of conjugated estrogens by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP1A2 substrates. If not feasible, avoid use of abametapir.acetazolamideMinor (1)acetazolamide will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.albiglutideMonitor Closely (1)conjugated estrogens decreases effects of albiglutide by pharmacodynamic antagonism. Use Caution/Monitor. Estrogens may decrease hypoglycemic effects of antidiabetics by impairing glucose tolerance. Monitor for glycemic control in diabetic patients.ambrisentanMonitor Closely (2)ambrisentan will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. ambrisentan will increase the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.amikacinMonitor Closely (1)amikacin will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.amiodaroneMonitor Closely (1)amiodarone will increase the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.amitriptylineMinor (1)conjugated estrogens, amitriptyline. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Estrogens and progestins may decr tricyclic antidepressant effects, while increasing TCA plasma concentration and adverse effects.amobarbitalMonitor Closely (1)amobarbital will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.amoxapineMinor (1)conjugated estrogens, amoxapine. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Estrogens and progestins may decr tricyclic antidepressant effects, while increasing TCA plasma concentration and adverse effects.anastrozoleSerious - Use Alternative (1)conjugated estrogens decreases effects of anastrozole