Dosing & Uses
Dosing Forms & Strengths
norethindrone/ethinyl estradiol/ferrous fumarate
tablet
- 0.4mg/35mcg (21 tabs) plus 75mg Fe (7 chewable tabs) (Nexesta Fe, Zenchent Fe, Wymzya Fe)
- 0.8mg/25mcg (24 tabs) plus 75mg Fe (4 chewable tabs) (Generess Fe, Kaitlib Fe, Layolis Fe)
Contraception
Follow Manufacturer's color-coding for sequence
Monophasic 21-days: 0.4 mg/35 mcg PO qDay (Days 1-21) plus 75mg ferrous fumarate PO qDay (Days 22-28)
Monophasic 24-days: 0.8 mg/25 mcg PO qDay (Days 1-24) plus 75mg ferrous fumarate PO qDay (Days 25-28)
Initiating after pregnancy
- Increased risk for venous thromboembolism (VTE) following delivery with combined hormonal contraceptives; risk declines rapidly after 21 days, but does not return to normal until 42 days after delivery
- CDC guidelines recommend waiting 3-6 weeks in postpartum women without additional VTE risks (MMWR July 7, 2011)
- Initiating after vaginal birth: Wait at least 3 weeks
- Initiating after caesarean section birth: Wait at least 6 weeks
- Women with other risk factors for VTE in addition to postpartum: Do not use combined hormonal contraceptives
Dosage Modifications
Renal impairment: Use caution; monitor blood pressure
Hepatic impairment: Do not use
Not recommended premenarche
Interactions
Interaction Checker
No Results
Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor
Contraindicated (2)
- ombitasvir/paritaprevir/ritonavir & dasabuvir
ombitasvir/paritaprevir/ritonavir & dasabuvir, ethinylestradiol. unspecified interaction mechanism. Contraindicated. Potential for increased ALT; contraceptive failure may occur when coadministered with protease inhibitors (ritonavir).
ethinylestradiol, ombitasvir/paritaprevir/ritonavir & dasabuvir. Either increases toxicity of the other by unspecified interaction mechanism. Contraindicated. ALT elevations >5 x ULN (including some >20 x ULN) observed in clinical trials when ethinyl estradiol was coadministered with ombitasvir/paritaprevir/ritonavir, with or without dasabuvir. Discontinue ethinyl estradiol-containing medications before initiating ombitasvir/paritaprevir/ritonavir, and/or dasabuvir. Restart ethinyl estradiol containing medication ~2 weeks after hepatitis C combination drug regimen completed. - tranexamic acid oral
tranexamic acid oral, ethinylestradiol. Either increases toxicity of the other by pharmacodynamic synergism. Contraindicated. Coadministration of tranexamic acid oral and combination hormonal contraceptives increases thrombotic risk.
Serious - Use Alternative (71)
- abametapir
abametapir will increase the level or effect of ethinylestradiol 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.
- amobarbital
amobarbital will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.
- anastrozole
ethinylestradiol decreases effects of anastrozole by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Anastrozole should not be given concurrently with any estrogens or estrogen-containing products.
- apalutamide
apalutamide will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP3A4 inducer, with drugs that are CYP3A4 substrates can result in lower exposure to these medications. Avoid or substitute another drug for these medications when possible. Evaluate for loss of therapeutic effect if medication must be coadministered. Adjust dose according to prescribing information if needed.
- armodafinil
armodafinil will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.
- atazanavir
atazanavir, ethinylestradiol. 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. .
- baloxavir marboxil
ferrous fumarate will decrease the level or effect of baloxavir marboxil by cation binding in GI tract. Avoid or Use Alternate Drug. Baloxavir may bind to polyvalent cations resulting in decreased absorption. Studies in monkeys showed concurrent use with calcium, aluminum, or iron caused significantly decreased plasma levels. Human studies not conducted.
- belzutifan
belzutifan will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of belzutifan with hormonal contraceptives may lead to contraceptive failure or increased breakthrough bleeding. Advise females of reproductive potential to use effective nonhormonal contraception. Based on animal studies, belzutifan can cause fetal harm.
- bosentan
bosentan will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.
- brigatinib
brigatinib will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Brigatinib induces CYP3A4 in vitro. Coadministration of hormonal contraceptives with brigatinib can result in decreased concentrations and loss of efficacy. Brigatinib can cause fetal harm. Women should use an effective nonhormonal method of contraception during treatment and for at least 4 months after the last brigatinib dose.
- butabarbital
butabarbital will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.
- calaspargase pegol
calaspargase pegol, ethinylestradiol. unknown mechanism. Avoid or Use Alternate Drug. Due to the potential for an indirect interaction between calaspargase pegol and oral contraceptives, concomitant use of these drugs is not recommended. Use another non-oral contraceptive method for females of childbearing potential.
- carbamazepine
ethinylestradiol will increase the level or effect of carbamazepine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.
carbamazepine will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. - conivaptan
conivaptan will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- demeclocycline
ferrous fumarate decreases levels of demeclocycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- dexamethasone
dexamethasone will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.
- doxycycline
ferrous fumarate decreases levels of doxycycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- efavirenz
efavirenz will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.
- elagolix
ethinylestradiol 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.
- eltrombopag
ferrous fumarate decreases levels of eltrombopag by inhibition of GI absorption. Applies only to oral form of both agents. Contraindicated. Separate by at least 4 hours.
- elvitegravir
elvitegravir will decrease the level or effect of ethinylestradiol by unknown mechanism. Avoid or Use Alternate Drug. Consider alternative nonhormonal methods of contraception to add or replace combination oral contraceptive
- encorafenib
encorafenib will decrease the level or effect of ethinylestradiol 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. Since 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.
- enoxaparin
ethinylestradiol decreases effects of enoxaparin by pharmacodynamic antagonism. Contraindicated. Risk of thromboembolic disorders.
- enzalutamide
enzalutamide will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- eslicarbazepine acetate
eslicarbazepine acetate will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Use additional or alternative nonhormonal birth control.
- exemestane
ethinylestradiol decreases effects of exemestane by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Exemestane should not be given concurrently with any estrogens or estrogen-containing products.
- fedratinib
ethinylestradiol will increase the level or effect of fedratinib by Other (see comment). Avoid or Use Alternate Drug. Avoid coadministration of fedratinib (a CYP3A4 and CYP2C19 substrate) with dual CYP3A4 and CYP2C19 inhibitor. Effect of coadministration of a dual CYP3A4 and CYP2C19 inhibitor with fedratinib has not been studied.
- fexinidazole
fexinidazole will increase the level or effect of ethinylestradiol by affecting hepatic enzyme CYP2E1 metabolism. Avoid or Use Alternate Drug. Fexinidazole inhibits CYP3A4. Coadministration may increase risk for adverse effects of CYP3A4 substrates.
- fleroxacin
ferrous fumarate decreases levels of fleroxacin by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- fosamprenavir
fosamprenavir, ethinylestradiol. unspecified interaction mechanism. Avoid or Use Alternate Drug. Coadministration may decrease amprenavir AUC, and may lead to loss of virologic response. Coadministration of fosamprenavir with ethinyl estradiol may alter hormone levels. Alternative methods of nonhormonal contraception are recommended.
- gemifloxacin
ferrous fumarate decreases levels of gemifloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- griseofulvin
griseofulvin will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.
- heparin
ethinylestradiol decreases effects of heparin by pharmacodynamic antagonism. Contraindicated. Risk of thromboembolic disorders.
- idelalisib
idelalisib will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substrates
- indinavir
indinavir, ethinylestradiol. 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 sulfate
isavuconazonium sulfate will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- ivosidenib
ivosidenib will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP3A4 substrates with ivosidenib or replace with alternate therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs.
- lesinurad
lesinurad decreases effects of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Use additional methods of nonhormonal contraception. Do not rely on hormonal contraception alone when taking lesinurad.
- letrozole
ethinylestradiol decreases effects of letrozole by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Letrozole should not be given concurrently with any estrogens or estrogen-containing products.
- levofloxacin
ferrous fumarate decreases levels of levofloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- lonafarnib
ethinylestradiol will increase the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of lonafarnib (a sensitive CYP3A substrate) with weak CYP3A inhibitors is unavoidable, reduce to, or continue lonafarnib at starting dose. Closely monitor for arrhythmias and events (eg, syncope, heart palpitations) since lonafarnib effect on QT interval is unknown.
- lopinavir
lopinavir, ethinylestradiol. 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. .
lopinavir will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. - lumacaftor/ivacaftor
lumacaftor/ivacaftor will decrease the level or effect of ethinylestradiol by unspecified interaction mechanism. Avoid or Use Alternate Drug. Avoid coadministration unless benefit outweighs risk. When coadministered, hormonal contraceptives are not a reliable method of effective birth control. Concomitant use may increase incidence of menstruation associated adverse effects (amenorrhea, dysmenorrhea, menorrhagia).
- metyrapone
ethinylestradiol decreases effects of metyrapone by unspecified interaction mechanism. Avoid or Use Alternate Drug. A subtherapeutic response to metyrapone can be seen in patients on estrogens, including oral contraceptives, that contain estrogen therapy. It may be advisable to discontinue estrogens prior to and during metyrapone administration.
- mifepristone
mifepristone will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- minocycline
ferrous fumarate decreases levels of minocycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- mobocertinib
mobocertinib will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of mobocertinib with hormonal contraceptives may lead to contraceptive failure or increased breakthrough bleeding. Advise females of reproductive potential to use effective non-hormonal contraception.
- modafinil
modafinil will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.
- moxifloxacin
ferrous fumarate decreases levels of moxifloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- mycophenolate
ferrous fumarate decreases levels of mycophenolate by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Interaction only with oral iron administration.
mycophenolate decreases effects of ethinylestradiol by unknown mechanism. Avoid or Use Alternate Drug. Patients should consider using an alternative or additional form of contraception. - nelfinavir
nelfinavir, ethinylestradiol. 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. .
nelfinavir will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. - ofloxacin
ferrous fumarate decreases levels of ofloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- nevirapine
nevirapine will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.
- oxcarbazepine
oxcarbazepine will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.
- oxytetracycline
ferrous fumarate decreases levels of oxytetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- pentobarbital
pentobarbital will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.
- phenobarbital
phenobarbital will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.
- phenytoin
phenytoin will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.
- primidone
primidone will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.
- quinidine
quinidine will increase the level or effect of ethinylestradiol by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
- ranolazine
ethinylestradiol will increase the level or effect of ranolazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- rifabutin
rifabutin will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.
- rifampin
rifampin will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.
- rifapentine
rifapentine will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.
- ritonavir
ritonavir, ethinylestradiol. 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. .
ritonavir will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. - saquinavir
saquinavir, ethinylestradiol. 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. .
saquinavir will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. - secobarbital
secobarbital will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.
- St John's Wort
St John's Wort will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.
- sugammadex sodium
sugammadex sodium decreases effects of ethinylestradiol by receptor binding competition. Avoid or Use Alternate Drug. In vitro binding studies showed that sugammadex may bind to progestogen, thereby decreasing progestogen exposure. Therefore, a sugammadex bolus dose is considered to be equivalent to missing dose(s) of hormonal contraceptives containing an estrogen or progestogen. If an oral contraceptive is taken on the same day of sugammadex, or the patient has a transdermal or implant hormonal contraceptive, the patient must use an additional, nonhormonal contraceptive method or back-up method of contraception (eg, condoms and spermicides) for the next 7 days.
- tetracycline
ferrous fumarate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.
- tipranavir
tipranavir, ethinylestradiol. 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. .
Monitor Closely (169)
- albiglutide
ethinylestradiol decreases effects of albiglutide 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.
- alosetron
ethinylestradiol will increase the level or effect of alosetron by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
- alprazolam
ethinylestradiol will increase the level or effect of alprazolam 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.
- aluminum hydroxide
aluminum hydroxide will decrease the level or effect of ferrous fumarate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- aminocaproic acid
ethinylestradiol, aminocaproic acid. Other (see comment). Use Caution/Monitor. Comment: Concomitant use may lead to additive hypercoagulability. Estrogens increase clotting factor production and platelet aggregation; aminocaproic acid inhibits fibrinolysis and activity of plasminogen.
- amoxicillin
amoxicillin 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.
- ampicillin
ampicillin 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.
- artemether/lumefantrine
artemether/lumefantrine will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- atogepant
ethinylestradiol will increase the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- atorvastatin
atorvastatin will increase the level or effect of ethinylestradiol by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
- axitinib
ethinylestradiol increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- bendamustine
ethinylestradiol increases levels of bendamustine by decreasing metabolism. Use Caution/Monitor. Bendamustine is metabolized to minimally active metabolites by CYP1A2. Ethinyl estradiol is a weak CYP1A2 inhibitor and concurrent administration may increase bendamustine concentrations in plasma. .
- bictegravir
ferrous fumarate will decrease the level or effect of bictegravir by cation binding in GI tract. Modify Therapy/Monitor Closely. Bictegravir and supplements containing iron can be taken together with food. Routine administration of bictegravir (under fasting conditions) simultaneously with, or 2 hr after, supplements containing iron is not recommended.
- caffeine
ethinylestradiol will increase the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
- calcium carbonate
calcium carbonate will decrease the level or effect of ferrous fumarate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- cefaclor
cefaclor 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.
- cefadroxil
cefadroxil 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.
- cefazolin
cefazolin 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.
- cefdinir
cefdinir 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.
- cefepime
cefepime 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.
- cefixime
cefixime 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.
- cefotaxime
cefotaxime 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.
- cefprozil
cefprozil 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.
- ceftazidime
ceftazidime 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.
- ceftibuten
ceftibuten 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.
- cefuroxime
cefuroxime 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.
- cenobamate
cenobamate will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP3A4 substrate, as needed, when coadministered with cenobamate.
cenobamate will decrease the level or effect of ethinylestradiol by unspecified interaction mechanism. Modify Therapy/Monitor Closely. Advise women to use additional or alternative non-hormonal birth control when concomitantly using cenobamate with oral contraceptives. - cephalexin
cephalexin 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.
- chloramphenicol
chloramphenicol 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.
- cimetidine
cimetidine will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
cimetidine will decrease the level or effect of ferrous fumarate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. - ciprofloxacin
ferrous fumarate decreases levels of ciprofloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Coadministration of ciprofloxacin with multivalent cation-containing products may reduce the bioavailability of ciprofloxacin by 90%. Administer ciprofloxacin at least 2 hours before or 6 hours after using these products. Use alternatives if available.
ciprofloxacin 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. - clarithromycin
clarithromycin will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Modify Therapy/Monitor Closely.
- deferasirox
deferasirox decreases levels of ferrous fumarate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Deferasirox chelates iron.
- clindamycin
clindamycin 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.
- clobazam
clobazam will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Clobazam is a weak CYP3A4 inducer; effectiveness of hormonal contraceptives may be diminished when given concurrently with clobazam. Additional non-hormonal forms of contraception are recommended.
- clonazepam
ethinylestradiol will increase the level or effect of clonazepam 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.
- cyclosporine
ethinylestradiol increases levels of cyclosporine by unknown mechanism. Use Caution/Monitor.
- dabrafenib
dabrafenib will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
- darunavir
darunavir will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. 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.
- dasatinib
ethinylestradiol will increase the level or effect of dasatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- deferasirox
deferasirox will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- deferiprone
ferrous fumarate decreases levels of deferiprone by enhancing GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Deferiprone may bind polyvalent cations (eg, iron, aluminum, and zinc), separate administration by at least 4 hr between deferiprone and other medications (eg, antacids), or supplements containing these polyvalent cations.
- deferoxamine
deferoxamine decreases levels of ferrous fumarate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Deferoxamine chelates iron.
- delafloxacin
ferrous fumarate will decrease the level or effect of delafloxacin by cation binding in GI tract. Modify Therapy/Monitor Closely. Oral delafloxacin form chelates with alkaline earth and transition metal cations. Administer oral delafloxacin at least 2 hr before or 6 hr after these agents.
- demeclocycline
demeclocycline 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.
- dexlansoprazole
dexlansoprazole will decrease the level or effect of ferrous fumarate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- diazepam
ethinylestradiol will increase the level or effect of diazepam 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.
- dicloxacillin
dicloxacillin 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.
- dolutegravir
ferrous fumarate will decrease the level or effect of dolutegravir by cation binding in GI tract. Modify Therapy/Monitor Closely. Administer dolutegravir 2 hr (dolutegravir or abacavir/dolutegravir/lamivudine) or 4 hr (dolutegravir/rilpivirine) before or 6 hr after taking medications containing polyvalent cations.
- doxycycline
doxycycline 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.
- elagolix
elagolix will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak-to-moderate CYP3A4 inducer. Monitor CYP3A substrates if coadministered. Consider increasing CYP3A substrate dose if needed.
- eltrombopag
ethinylestradiol will increase the level or effect of eltrombopag by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
- elvitegravir/cobicistat/emtricitabine/tenofovir DF
elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP3A4 inhibitor; contraindicated with CYP3A4 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.
- erythromycin base
erythromycin base 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.
- erythromycin ethylsuccinate
erythromycin ethylsuccinate 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.
- erythromycin lactobionate
erythromycin lactobionate 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.
- erythromycin stearate
erythromycin 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.
- esomeprazole
esomeprazole will decrease the level or effect of ferrous fumarate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- etravirine
etravirine 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 solution
ethinylestradiol, 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 suspension
ethinylestradiol, 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.
- famotidine
famotidine will decrease the level or effect of ferrous fumarate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- fedratinib
fedratinib 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.
- finerenone
ethinylestradiol 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.
- flibanserin
ethinylestradiol 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.
- fluconazole
fluconazole will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- fluvoxamine
ethinylestradiol will increase the level or effect of fluvoxamine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
- fostemsavir
fostemsavir 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.
- gemifloxacin
gemifloxacin 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.
- grapefruit
grapefruit will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- green tea
green tea, ferrous fumarate. Other (see comment). Use Caution/Monitor. Comment: When possible, do not consume green tea or green tea extract within 1 hour before or 2 hours after giving iron salts.
ethinylestradiol increases levels of green tea by decreasing elimination. Use Caution/Monitor. - hemin
ethinylestradiol decreases effects of hemin by pharmacodynamic antagonism. Use Caution/Monitor. Drugs that increase delta-aminolevulinic acid synthetase may decrease hemin effect.
- ibandronate
ferrous fumarate decreases levels of ibandronate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
- hyaluronidase
ethinylestradiol 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.
- ibuprofen/famotidine
ibuprofen/famotidine will decrease the level or effect of ferrous fumarate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- iloperidone
iloperidone 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 aspart
ethinylestradiol 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 degludec
ethinylestradiol decreases effects of insulin degludec by pharmacodynamic antagonism. Use Caution/Monitor. Estrogens may impair glucose tolerance.
- insulin degludec/insulin aspart
ethinylestradiol decreases effects of insulin degludec/insulin aspart by pharmacodynamic antagonism. Use Caution/Monitor. Estrogens may impair glucose tolerance.
- insulin detemir
ethinylestradiol 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 glargine
ethinylestradiol 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 glulisine
ethinylestradiol 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 inhaled
ethinylestradiol decreases effects of insulin inhaled by pharmacodynamic antagonism. Use Caution/Monitor. Estrogens may impair glucose tolerance.
- insulin lispro
ethinylestradiol 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 NPH
ethinylestradiol 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 human
ethinylestradiol 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 sulfate
ethinylestradiol will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- istradefylline
istradefylline 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.
- itraconazole
itraconazole 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.
- ketoconazole
ketoconazole 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.
- lamotrigine
ethinylestradiol 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.
- lansoprazole
lansoprazole will decrease the level or effect of ferrous fumarate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- lapatinib
ethinylestradiol will increase the level or effect of lapatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- lemborexant
ethinylestradiol 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.
- levodopa
ferrous fumarate decreases levels of levodopa by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Oral administration of iron salts should be separated from levodopa by at least 2 hours.
- levofloxacin
levofloxacin 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.
- levothyroxine
ferrous fumarate decreases levels of levothyroxine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
- liothyronine
ferrous fumarate decreases levels of liothyronine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
- liraglutide
ethinylestradiol 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
lixisenatide 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.
- lomitapide
ethinylestradiol increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lomitapide dose should not exceed 30 mg/day.
- lorlatinib
lorlatinib will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- lumefantrine
lumefantrine will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- metformin
ethinylestradiol decreases effects of metformin by pharmacodynamic antagonism. Use Caution/Monitor.
- methyldopa
ferrous fumarate decreases levels of methyldopa by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
- metronidazole
metronidazole 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.
- mexiletine
ethinylestradiol will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
- midazolam
ethinylestradiol 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 intranasal
ethinylestradiol 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.
- mifepristone
mifepristone decreases effects of ferrous fumarate by pharmacodynamic antagonism. Use Caution/Monitor. Backup contraceptive method recommended.
mifepristone decreases effects of ethinylestradiol by pharmacodynamic antagonism. Use Caution/Monitor. Backup contraceptive method recommended. - minocycline
minocycline 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.
- nizatidine
nizatidine will decrease the level or effect of ferrous fumarate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- mitotane
mitotane 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.
- moxifloxacin
moxifloxacin 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.
- nafcillin
nafcillin will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- neomycin PO
neomycin 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.
- nicardipine
ethinylestradiol will increase the level or effect of nicardipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- nilotinib
ethinylestradiol will increase the level or effect of nilotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- nitrofurantoin
nitrofurantoin 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.
- ofloxacin
ofloxacin 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.
- olanzapine
ethinylestradiol will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
- omadacycline
ferrous fumarate will decrease the level or effect of omadacycline by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Multivalent cation-containing products may impair absorption of tetracyclines, which may decrease its efficacy. Separate dosing of tetracyclines from these products.
- omeprazole
omeprazole will decrease the level or effect of ferrous fumarate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- pancrelipase
pancrelipase decreases levels of ferrous fumarate by enhancing GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Levels of iron salts may decrease with concomitant administration of digestive enzymes.
- pantoprazole
pantoprazole will decrease the level or effect of ferrous fumarate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- paromomycin
paromomycin 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.
- penicillamine
ferrous fumarate decreases levels of penicillamine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Interaction only with oral iron administration.
- penicillin G aqueous
penicillin G aqueous decreases levels of ethinylestradiol by increasing metabolism. Use Caution/Monitor. Risk of oral contraceptive failure.
- penicillin VK
penicillin 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.
- pioglitazone
pioglitazone decreases levels of ethinylestradiol by unknown mechanism. Use Caution/Monitor.
- posaconazole
posaconazole will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- quinupristin/dalfopristin
quinupristin/dalfopristin will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- rabeprazole
rabeprazole will decrease the level or effect of ferrous fumarate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- ramelteon
ethinylestradiol will increase the level or effect of ramelteon by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
- rasagiline
ethinylestradiol 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.
- ribociclib
ribociclib will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- romidepsin
romidepsin decreases effects of ethinylestradiol by receptor binding competition. Use Caution/Monitor.
- ropinirole
ethinylestradiol 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. - rucaparib
rucaparib 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.
- rufinamide
rufinamide 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. .
- sarecycline
ferrous fumarate will decrease the level or effect of sarecycline by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Multivalent cation-containing products may impair absorption of tetracyclines, which may decrease its efficacy. Separate dosing of tetracyclines from these products.
- selegiline
ethinylestradiol increases levels of selegiline by Other (see comment). Use Caution/Monitor. Comment: Oral contraceptives inhibit the N demethylatin of selegiline.
- selegiline transdermal
ethinylestradiol increases levels of selegiline transdermal by Other (see comment). Use Caution/Monitor. Comment: Oral contraceptives inhibit the N demethylatin of selegiline.
- siltuximab
siltuximab, ethinylestradiol. Other (see comment). Use Caution/Monitor. Comment: CYP450 activity in the liver is down regulated by infection and inflammation stimuli including cytokines (eg, IL-6); inhibition of IL-6 by siltuximab may restore CYP450 enzymatic activity; caution if coadministered with CYP substrates that have a narrow therapeutic index.
- sodium bicarbonate
sodium bicarbonate will decrease the level or effect of ferrous fumarate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- sodium citrate/citric acid
sodium citrate/citric acid will decrease the level or effect of ferrous fumarate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.
- sodium picosulfate/magnesium oxide/anhydrous citric acid
sodium picosulfate/magnesium oxide/anhydrous citric acid decreases levels of ferrous fumarate by cation binding in GI tract. Use Caution/Monitor. Take at least 2 hours before and not less than 6 hours after administration of sodium picosulfate, magnesium oxide and anhydrous citric acid to avoid magnesium chelation.
- sodium sulfate/?magnesium sulfate/potassium chloride
sodium sulfate/?magnesium sulfate/potassium chloride decreases levels of ferrous fumarate by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Administer iron products at least 2 hr before and no less than 6 hr after each dose to avoid chelation with magnesium. .
- sodium sulfate/potassium sulfate/magnesium sulfate
sodium sulfate/potassium sulfate/magnesium sulfate decreases levels of ferrous fumarate by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Administer iron products at least 2 hr before and no less than 6 hr after each dose to avoid chelation with magnesium. .
- sodium zirconium cyclosilicate
sodium zirconium cyclosilicate will decrease the level or effect of ferrous fumarate by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Check specific recommendations for drugs that exhibit pH-dependent solubility that may affect their systemic exposure and efficacy. In general, administer drugs at least 2 hr before or after sodium zirconium cyclosilicate.
- stiripentol
stiripentol, ethinylestradiol. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP3A4 inhibitor and inducer. Monitor CYP3A4 substrates coadministered with stiripentol for increased or decreased effects. CYP3A4 substrates may require dosage adjustment.
- sulfadiazine
sulfadiazine 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.
- sulfamethoxazole
sulfamethoxazole 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.
- sulfisoxazole
sulfisoxazole 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.
- tacrolimus
ethinylestradiol will increase the level or effect of tacrolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- tazemetostat
tazemetostat will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
ethinylestradiol will increase the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. - tecovirimat
tecovirimat will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.
- teriflunomide
teriflunomide increases levels of ethinylestradiol by unknown mechanism. Use Caution/Monitor.
- tetracycline
tetracycline 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.
- theophylline
ethinylestradiol will increase the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
- thyroid desiccated
ferrous fumarate decreases levels of thyroid desiccated by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
- ticarcillin
ticarcillin 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.
- tigecycline
tigecycline 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.
- tinidazole
ethinylestradiol will increase the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- tizanidine
ethinylestradiol will increase the level or effect of tizanidine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Monitor for tizanidine adverse effects (eg, hypotension or bradycardia)
- tolterodine
ethinylestradiol will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- triazolam
ethinylestradiol will increase the level or effect of triazolam 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.
- trientine
trientine, ferrous fumarate. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hr.
- trimethoprim
trimethoprim 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.
Minor (37)
- acetohydroxamic acid
acetohydroxamic acid decreases levels of ferrous fumarate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- amitriptyline
ethinylestradiol, amitriptyline. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Estrogens and progestins may decr tricyclic antidepressant effects, while increasing TCA plasma concentration and adverse effects.
- amoxapine
ethinylestradiol, amoxapine. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Estrogens and progestins may decr tricyclic antidepressant effects, while increasing TCA plasma concentration and adverse effects.
- antipyrine
ethinylestradiol will increase the level or effect of antipyrine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.
- asenapine
ethinylestradiol will increase the level or effect of asenapine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.
- calcium acetate
calcium acetate decreases levels of ferrous fumarate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
ferrous fumarate increases levels of calcium acetate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. - calcium carbonate
calcium carbonate decreases levels of ferrous fumarate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
ferrous fumarate increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. - calcium chloride
calcium chloride decreases levels of ferrous fumarate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
ferrous fumarate increases levels of calcium chloride by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. - calcium citrate
calcium citrate decreases levels of ferrous fumarate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
ferrous fumarate increases levels of calcium citrate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. - calcium gluconate
calcium gluconate decreases levels of ferrous fumarate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
ferrous fumarate increases levels of calcium gluconate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. - carbidopa
ferrous fumarate decreases levels of carbidopa by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- clarithromycin
ethinylestradiol will increase the level or effect of clarithromycin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- clomipramine
ethinylestradiol will increase the level or effect of clomipramine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.
- desipramine
ethinylestradiol, desipramine. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Oxidative metabolism of TCAs may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Potential for increased TCA adverse effects.
- didanosine
didanosine will decrease the level or effect of ferrous fumarate by increasing gastric pH. Applies only to oral form of both agents. Minor/Significance Unknown. Applies to didanosine chewable tablets and powder for oral solution; administer 2 hr before or several hours after didanosine oral solution or chewable tablet administration
- dosulepin
ethinylestradiol, dosulepin. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Oxidative metabolism of TCAs may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Potential for increased TCA adverse effects.
- doxepin
ethinylestradiol, doxepin. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Oxidative metabolism of TCAs may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Potential for increased TCA adverse effects.
- duloxetine
ethinylestradiol will increase the level or effect of duloxetine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.
- enasidenib
enasidenib, ethinylestradiol. 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.
- eplerenone
ethinylestradiol will increase the level or effect of eplerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- felbamate
felbamate decreases levels of ethinylestradiol by unknown mechanism. Minor/Significance Unknown.
- frovatriptan
ethinylestradiol will increase the level or effect of frovatriptan by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.
- gymnema
gymnema decreases levels of ferrous fumarate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- imipramine
ethinylestradiol, imipramine. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Oxidative metabolism of TCAs may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Potential for increased TCA adverse effects.
- manganese
ferrous fumarate decreases levels of manganese by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- mineral oil
mineral oil decreases levels of ethinylestradiol by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- naratriptan
ethinylestradiol increases effects of naratriptan by unspecified interaction mechanism. Minor/Significance Unknown. The clinical implication of these interactions is unknown.
- nefazodone
nefazodone will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- nortriptyline
ethinylestradiol, nortriptyline. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Oxidative metabolism of TCAs may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Potential for increased TCA adverse effects.
- protriptyline
ethinylestradiol, protriptyline. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Oxidative metabolism of TCAs may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Potential for increased TCA adverse effects.
- ramelteon
ethinylestradiol will increase the level or effect of ramelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- rosuvastatin
rosuvastatin increases levels of ethinylestradiol by unspecified interaction mechanism. Minor/Significance Unknown.
- ruxolitinib
ethinylestradiol will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- tizanidine
ethinylestradiol increases levels of tizanidine by unspecified interaction mechanism. Minor/Significance Unknown.
- trazodone
ethinylestradiol, trazodone. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Oxidative metabolism of TCAs may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Potential for increased TCA adverse effects.
- trimipramine
ethinylestradiol, trimipramine. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Oxidative metabolism of TCAs may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Potential for increased TCA adverse effects.
- vitamin E
vitamin E decreases levels of ferrous fumarate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
Adverse Effects
>10%
Edema
Weakness
Anorexia
Amenorrhea
Breakthrough bleeding
Change in menstrual flow
Spotting
Frequency Not Defined
Deep vein thrombosis
Thrombophlebitis
Depression
Dizziness
Headache
Nervousness
Somnolence
Breast tenderness
Galactorrhea
Abdominal pain
Nausea
Vomiting
Weight change
Cholestatic jaundice
Warnings
Black Box Warnings
Cardiovascular risks
- Estrogens with and without progestins should not be used to prevent cardiovascular diseaseEstrogens plus progestins: Women’s Health Initiative (WHI)
- Estrogen Plus Progestin substudy reported increased risks of myocardial infarction, stroke, invasive breast cancer, pulmonary emboli, and deep vein thrombosis (DVT) in postmenopausal women (aged 50-79 yr) during 5.6 yr of treatment with daily PO conjugated estrogens (CE 0.625 mg) combined with medroxyprogesterone acetate (MPA 2.5 mg) compared with placebo
- Estrogens alone: The estrogen alone substudy of the WHI Study reported increased risks of stroke & DVT in postmenopausal women (aged 50-79 yr) during 6.8 yr of treatment with oral conjugated estrogens (0.625 mg/day) alone compared 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 yr or older during 4 yr of treatment with daily CE 0.625 mg combined with MPA 2.5 mg, compared w/ placebo
- Estrogens alone: A substudy of the WHIMS reported an increased risk of developing probable dementia in postmenopausal women aged 65 yr or older during 5.2 yr of treatment with conjugated estrogens 0.625 mg alone compared with placebo
- Unknown whether these findings apply to younger postmenopausal women
Dose & duration
- In the absence of comparable data, these risks should be assumed to be similar for other doses of CE and MPA and other combinations and dosage forms of estrogens and progestins
- Because of these risks, estrogens with or without progestins should be prescribed at lowest effective dose and for shortest duration consistent with treatment goals and individual risks
Cigarette smoking & risk of cardiovascular disease
- Cigarette smoking increases risk of serious cardiovascular adverse effects from combination hormonal contraceptive use
- This risk increases w/ age (>35 yr) and with heavy smoking (15 or more cigarettes/day)
- Advise women who use hormonal oral contraceptives not to smoke
Contraindications
Documented hypersensitivity
Active or history of breast cancer
Arterial thromboembolic disease (stroke, MI), thrombophlebitis, DVT/PE, thrombogenic valvular disease
Estrogen-dependent neoplasia
Liver disease, liver tumors
Undiagnosed abnormal vaginal bleeding
Uncontrolled hypertension
Diabetes mellitus with vascular involvement
Jaundice with prior oral contraceptive use
Cautions
Acitretin inhibits contraceptive efficacy of norethindrone preparations
Family history of breast cancer and or DVT/PE, current/history of depression, endometriosis, DM, HTN, bone mineral density changes, renal/hepatic impairment, bone metabolic disease, SLE; conditions exacerbated by fluid retention (eg, migraine, asthma, epilepsy)
Discontinue if the following develop jaundice, visual problems (may cause contact lens intolerance), any signs of VTE, migraine with unusual severity, significang blood pressure increase, severe depression, increased risk of thromboembolic complications after surgery
Discontinue 4 week before major surgery or prolonged immobilization
Patients on warfarin, oral anticoagulants (increase in anticoagulant dose may be warranted)
Some studies link OCP use with increased risk of breast cancer, whereas other studies have not shown a change in risk; woman's risk depends on conditions where naturally high hormone levels persist for long periods of time including early onset menstruation before age 12, late onset menopause, after age 55, first child after age 30, nulliparity
Increased risk of cervical cancer with OCP use, however HPV remains as main risk factor for this cancer; evidence suggests long-term use of OCPs, 5 or more years, may be associated with increased risk
Increased risk of liver cancer with OCP use; risk increases with longer duration of OCP use
CDC guidelines recommend waiting at least 3 weeks following vaginal birth or 6 weeks after cesarean section to decrease risk for venous thromboembolism before initiating combined hormonal contraceptives; women with additional risk factors for VTE (besides postpartum) should not use combined hormonal contraceptives (MMWR July 7, 2011)
Pregnancy & Lactation
Pregnancy Category: X
Lactation: small amounts of steroids are excreted in breast milk; estrogens may reduce quality/quantity of milk; may be prudent to use other forms of birth control until full weaning (AAP Committee states compatible with nursing)
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Ethinyl Estradiol (EE): Reduces LHRH release from hypothalamus, reduces gonadotropin release from pituitary; increases synthesis of DNA, RNA, and various proteins in target tissues
Norethindrone acetate: progestin; inhibits gonadotropin secretion of gonadotropins from pituitary; prevents follicular maturation and ovulation, stimulates growth of mammary tissues
Pharmacokinetics
Peak Plasma Time: 8 hr (EE); 1-2 hr (norethindrone)
Protein binding: EE 80%; norethindrone 61%
Both components are metabolized in the liver; estradiol undergoes extensive first-pass metabolism
Bioavailability: 43-55% (ethinyl estradiol)
Vd: 2-4 L/kg (ethinyl estradiol)
Ethinyl estradiol metabolites: Estriol, estrone
Norethindrone metabolites: Sulfate and glucuronide metabolites (inactive)
Half-life elimination: 4-13 hr (norethindrone PO); 19-24hr (ethinyl estradiol)
Excretion
- Ethinyl estradiol: Urine as conjugates, most estrogens are also excreted in bile and undergo enterohepatic recycling
- Norethindrone: 33-81% (urine); 35-43% (feces)
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Formulary
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