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 conjugated estrogens 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 conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.phenindioneSerious - Use Alternative (1)conjugated estrogens decreases effects of phenindione by pharmacodynamic antagonism. Contraindicated. Risk of thromboembolic disorders.phenobarbitalMonitor Closely (2)phenobarbital will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. phenobarbital will decrease the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.phenytoinMonitor Closely (2)phenytoin will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. phenytoin will decrease the level or effect of conjugated estrogens 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 conjugated estrogens by pharmacodynamic antagonism. Minor/Significance Unknown.pivmecillinamMonitor Closely (1)pivmecillinam 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.pleurisy rootMinor (1)pleurisy root decreases effects of conjugated estrogens by unspecified interaction mechanism. Minor/Significance Unknown. Theoretical interaction.posaconazoleMonitor Closely (1)posaconazole will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.prednisoneMonitor Closely (1)prednisone will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.pretomanidSerious - Use Alternative (1)pretomanid will increase the level or effect of conjugated estrogens by Other (see comment). Avoid or Use Alternate Drug. In vitro studies demonstrated that pretomanid significantly inhibits OAT3; monitor for increased adverse effects and consider dosage reduction for OAT3 substrates.primidoneMonitor Closely (1)primidone will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.progesterone, naturalMinor (1)progesterone, natural, conjugated estrogens. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Combination may produce breast tenderness.protamineSerious - Use Alternative (1)conjugated estrogens decreases effects of protamine by pharmacodynamic antagonism. Contraindicated. Risk of thromboembolic disorders.protriptylineMinor (1)conjugated 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.pyridoxineMinor (1)conjugated estrogens decreases levels of pyridoxine by altering metabolism. Minor/Significance Unknown.pyridoxine (Antidote)Minor (1)conjugated estrogens decreases levels of pyridoxine (Antidote) by altering metabolism. Minor/Significance Unknown.quercetinMonitor Closely (1)quercetin will decrease the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.quinidineSerious - Use Alternative (1)quinidine will increase the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.quinupristin/dalfopristinMonitor Closely (2)quinupristin/dalfopristin will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. quinupristin/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.ranolazineMonitor Closely (1)ranolazine will increase the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.ribociclibMonitor Closely (1)ribociclib will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.rifabutinSerious - Use Alternative (1)rifabutin will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.rifampinMonitor Closely (1)rifampin will decrease the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.rifapentineMonitor Closely (1)rifapentine will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.ritonavirMonitor Closely (2)ritonavir 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.ropiniroleMinor (1)conjugated estrogens increases levels of ropinirole by unspecified interaction mechanism. Minor/Significance Unknown.rose hipsMinor (1)conjugated estrogens decreases levels of rose hips by increasing elimination. Minor/Significance Unknown.roxithromycinMonitor Closely (1)roxithromycin 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.rufinamideMonitor Closely (1)rufinamide will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.saquinavirMonitor Closely (1)saquinavir will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.secobarbitalMonitor Closely (1)secobarbital will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.simvastatinMonitor Closely (1)simvastatin will increase the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.sirolimusMonitor Closely (1)sirolimus will increase the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.somapacitanMonitor Closely (1)conjugated 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 WortMonitor Closely (1)St John's Wort will decrease the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)St John's Wort will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.stiripentolMonitor Closely (1)stiripentol, 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.streptomycinMonitor Closely (1)streptomycin 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.sulfadiazineMonitor Closely (1)sulfadiazine 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.sulfamethoxazoleMonitor Closely (1)sulfamethoxazole 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.sulfisoxazoleMonitor Closely (1)sulfisoxazole 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.tacrolimusMonitor Closely (1)tacrolimus will increase the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.tazemetostatMonitor Closely (1)conjugated estrogens 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 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.teicoplaninMonitor Closely (1)teicoplanin 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.temocillinMonitor Closely (1)temocillin 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.tenapanorMonitor Closely (1)tenapanor 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.teniposideMonitor Closely (1)teniposide will increase the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.tesamorelinMonitor Closely (1)tesamorelin will decrease the level or effect of conjugated estrogens by altering metabolism. Use Caution/Monitor. May decrease efficacy; monitortetracyclineMonitor Closely (1)tetracycline 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.ticarcillinMonitor Closely (1)ticarcillin 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.tigecyclineMonitor Closely (1)tigecycline 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.tobramycinMonitor Closely (1)tobramycin 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.tolvaptanMonitor Closely (1)tolvaptan will increase the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.topiramateMonitor Closely (1)topiramate will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.trazodoneMonitor Closely (1)trazodone will decrease the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Minor (1)conjugated 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.trimethoprimMonitor Closely (1)trimethoprim 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.trimipramineMinor (1)conjugated 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.tucatinibSerious - Use Alternative (1)tucatinib will increase the level or effect of conjugated estrogens 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)conjugated 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 acidMonitor Closely (1)conjugated estrogens will decrease the level or effect of valproic acid by increasing elimination. Modify Therapy/Monitor Closely. May lead to increased seizure frequencyvancomycinMonitor Closely (1)vancomycin 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.verapamilMonitor Closely (2)verapamil 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.voriconazoleMonitor Closely (1)voriconazole will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.zafirlukastMonitor Closely (1)zafirlukast will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. >10% Abdominal pain (15-17%) Back pain (13-14%) Breast enlargement Breast tenderness (7-12%) Headache (26-32%) Arthralgia (7-14%) Pharyngitis (10-12%) Sinusitis (6-11%) Diarrhea (6-7%) 1-10% Depression (5-8%) Dizziness (4-6%) Nervousness (2-5%) Flatulence (6-7%) Vaginitis (5-7%) Leukorrhea (4-7%) Leg cramps (3-7%) Increased cough (4-7%) Pruritus (4-5%) Frequency Not Defined Amenorrhea Breakthrough bleeding Corneal curvation change Melasma Spotting Vaginal moniliasis Weight changes Black Box Warnings Estrogens increase risk of endometrial cancer Close clinical surveillance of all women taking estrogens is important Adequate diagnostic measures, including endometrial sampling when indicated, should be undertaken to rule out malignancy in all cases of undiagnosed persistent or recurring abnormal vaginal bleeding There is no evidence that the use of "natural" estrogens results in a different endometrial risk profile than the use of synthetic estrogens at equivalent estrogen doses Increased risk of breast cancer Using conjugated estrogens in combination with medroxyprogesterone increases risk of invasive breast cancer Cardiovascular risks Estrogens with or without progestins should not be used to prevent cardiovascular disease Estrogens plus progestins: Women’s Health Initiative (WHI) Estrogen Plus Progestin substudy reported increased risks of myocardial infarction (MI), stroke, invasive breast cancer, pulmonary embolism (PE), and deep vein thrombosis (DVT) in postmenopausal women (aged 50-79 years) during 5.6 years of treatment with daily PO conjugated estrogens (0.625 mg) combined with medroxyprogesterone acetate (2.5 mg) in comparison with placebo Estrogens alone: A substudy of the WHI study reported increased risk for stroke and DVT in postmenopausal women (aged 50-79 years) during 6.8 years of treatment with daily PO conjugated estrogens (0.625 mg) alone in comparison with placebo Dementia risks Estrogens with or without progestins should not be used to prevent dementia Women's Health Initiative Memory Study (WHIMS), a substudy of the WHI study, reported increased risk of developing probable dementia in postmenopausal women aged ≥65 years during 4 years of treatment with daily PO conjugated estrogens (0.625) mg combined with medroxyprogesterone acetate (2.5 mg) in comparison with placebo Estrogens alone: A substudy of the WHIMS reported increased risk of developing probable dementia in postmenopausal women aged ≥65 years during 5.2 years of