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Drug Interactions between bexarotene and ethinyl estradiol / ethynodiol

This report displays the potential drug interactions for the following 2 drugs:

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Interactions between your drugs

Major

ethinyl estradiol bexarotene

Applies to: ethinyl estradiol / ethynodiol and bexarotene

ADDITIONAL CONTRACEPTION RECOMMENDED: There are no data concerning the potential effect of bexarotene on hormonal contraceptives. Presumably, coadministration with bexarotene may decrease the efficacy of contraceptives containing low-dose estrogens and progestins due to its induction of CYP450 3A4, the isoenzyme that is primarily responsible for the metabolic clearance of sex hormones.

MANAGEMENT: Women using low-dose hormonal contraceptives should be advised of the risk of breakthrough bleeding and unintended pregnancy during concomitant therapy with bexarotene. Because use of bexarotene is likely associated with major birth defects, it is particularly important that patients not become pregnant during treatment. Therefore, hormonal contraceptives should not be used as the sole method of birth control in women of childbearing potential treated with bexarotene. Product labeling recommends that two reliable forms of contraception, one non-hormonal, be used simultaneously during bexarotene therapy and for at least one month following discontinuation of therapy. Input from a gynecologist or similar expert on adequate contraception, including emergency contraception, should be sought as needed. Intrauterine systems are unlikely to be significantly affected because of their local action.

References

  1. (2001) "Product Information. Targretin (bexarotene)." Ligand Pharmaceuticals
  2. Faculty of Sexual & Reproductive Healthcare (2016) "FSRH Clinical Guidance: Drug Interactions with Hormonal Contraception. file:///C:/Users/df033684/Downloads/ceuguidancedruginteractionshormonal.pdf"

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Major

ethynodiol bexarotene

Applies to: ethinyl estradiol / ethynodiol and bexarotene

ADDITIONAL CONTRACEPTION RECOMMENDED: There are no data concerning the potential effect of bexarotene on hormonal contraceptives. Presumably, coadministration with bexarotene may decrease the efficacy of contraceptives containing low-dose estrogens and progestins due to its induction of CYP450 3A4, the isoenzyme that is primarily responsible for the metabolic clearance of sex hormones.

MANAGEMENT: Women using low-dose hormonal contraceptives should be advised of the risk of breakthrough bleeding and unintended pregnancy during concomitant therapy with bexarotene. Because use of bexarotene is likely associated with major birth defects, it is particularly important that patients not become pregnant during treatment. Therefore, hormonal contraceptives should not be used as the sole method of birth control in women of childbearing potential treated with bexarotene. Product labeling recommends that two reliable forms of contraception, one non-hormonal, be used simultaneously during bexarotene therapy and for at least one month following discontinuation of therapy. Input from a gynecologist or similar expert on adequate contraception, including emergency contraception, should be sought as needed. Intrauterine systems are unlikely to be significantly affected because of their local action.

References

  1. (2001) "Product Information. Targretin (bexarotene)." Ligand Pharmaceuticals
  2. Faculty of Sexual & Reproductive Healthcare (2016) "FSRH Clinical Guidance: Drug Interactions with Hormonal Contraception. file:///C:/Users/df033684/Downloads/ceuguidancedruginteractionshormonal.pdf"

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Drug and food interactions

Moderate

bexarotene food

Applies to: bexarotene

ADJUST DOSING INTERVAL: Food may enhance the oral bioavailability of bexarotene. In one clinical study, bexarotene peak plasma concentration (Cmax) and systemic exposure (AUC) resulting from a 75 to 300 mg dose were 35% and 48% higher, respectively, when administered after a fat-containing meal relative to a glucose solution. In all clinical trials, patients were instructed to take bexarotene with or immediately following a meal.

Coadministration with inhibitors of CYP450 3A4 such as grapefruit juice may theoretically increase the plasma concentrations of bexarotene. In vitro studies suggest that bexarotene is metabolized by CYP450 3A4. However, concomitant administration with multiple doses of ketoconazole, a potent CYP450 3A4 inhibitor, did not alter bexarotene plasma concentrations, which would imply that bexarotene elimination is not substantially dependent on CYP450 3A4 metabolism in vivo.

MANAGEMENT: Because safety and efficacy data are based upon administration with food, bexarotene should be administered once daily with a meal. Patients may want to avoid consuming large amounts of grapefruit or grapefruit juice.

References

  1. (2001) "Product Information. Targretin (bexarotene)." Ligand Pharmaceuticals
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics."

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Minor

ethinyl estradiol food

Applies to: ethinyl estradiol / ethynodiol

Coadministration with grapefruit juice may increase the bioavailability of oral estrogens. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall induced by certain compounds present in grapefruits. In a small, randomized, crossover study, the administration of ethinyl estradiol with grapefruit juice (compared to herbal tea) increased peak plasma drug concentration (Cmax) by 37% and area under the concentration-time curve (AUC) by 28%. Based on these findings, grapefruit juice is unlikely to affect the overall safety profile of ethinyl estradiol. However, as with other drug interactions involving grapefruit juice, the pharmacokinetic alterations are subject to a high degree of interpatient variability. Also, the effect on other estrogens has not been studied.

References

  1. Weber A, Jager R, Borner A, et al. (1996) "Can grapefruit juice influence ethinyl estradiol bioavailability?" Contraception, 53, p. 41-7
  2. Schubert W, Eriksson U, Edgar B, Cullberg G, Hedner T (1995) "Flavonoids in grapefruit juice inhibit the in vitro hepatic metabolism of 17B-estradiol." Eur J Drug Metab Pharmacokinet, 20, p. 219-24

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Minor

ethinyl estradiol food

Applies to: ethinyl estradiol / ethynodiol

The central nervous system effects and blood levels of ethanol may be increased in patients taking oral contraceptives, although data are lacking and reports are contradictory. The mechanism may be due to enzyme inhibition. Consider counseling women about this interaction which is unpredictable.

References

  1. Hobbes J, Boutagy J, Shenfield GM (1985) "Interactions between ethanol and oral contraceptive steroids." Clin Pharmacol Ther, 38, p. 371-80

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Minor

ethynodiol food

Applies to: ethinyl estradiol / ethynodiol

The central nervous system effects and blood levels of ethanol may be increased in patients taking oral contraceptives, although data are lacking and reports are contradictory. The mechanism may be due to enzyme inhibition. Consider counseling women about this interaction which is unpredictable.

References

  1. Hobbes J, Boutagy J, Shenfield GM (1985) "Interactions between ethanol and oral contraceptive steroids." Clin Pharmacol Ther, 38, p. 371-80

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Therapeutic duplication warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.

See also

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Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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