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Drug Interactions between encorafenib 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 encorafenib

Applies to: ethinyl estradiol / ethynodiol and encorafenib

GENERALLY AVOID: Coadministration with encorafenib may decrease the plasma concentrations and efficacy of contraceptive hormones. The proposed mechanism is induction of CYP450 3A4, the isoenzyme primarily responsible for the metabolic clearance of sex hormones. Although specific pharmacokinetic studies have not been conducted, encorafenib has been shown in vitro to induce CYP450 3A4 at clinically relevant plasma concentrations.

MANAGEMENT: Hormonal contraceptives, including oral, injectable, transdermal, and implantable forms, may not be reliable during concomitant therapy with encorafenib. Because encorafenib can cause fetal harm, it is particularly important that patients not become pregnant during treatment. Therefore, females of reproductive potential should use an effective, nonhormonal method of contraception during treatment and for 2 weeks after the final dose of encorafenib. 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. (2018) "Product Information. Braftovi (encorafenib)." Array BioPharma Inc.

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Major

ethynodiol encorafenib

Applies to: ethinyl estradiol / ethynodiol and encorafenib

GENERALLY AVOID: Coadministration with encorafenib may decrease the plasma concentrations and efficacy of contraceptive hormones. The proposed mechanism is induction of CYP450 3A4, the isoenzyme primarily responsible for the metabolic clearance of sex hormones. Although specific pharmacokinetic studies have not been conducted, encorafenib has been shown in vitro to induce CYP450 3A4 at clinically relevant plasma concentrations.

MANAGEMENT: Hormonal contraceptives, including oral, injectable, transdermal, and implantable forms, may not be reliable during concomitant therapy with encorafenib. Because encorafenib can cause fetal harm, it is particularly important that patients not become pregnant during treatment. Therefore, females of reproductive potential should use an effective, nonhormonal method of contraception during treatment and for 2 weeks after the final dose of encorafenib. 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. (2018) "Product Information. Braftovi (encorafenib)." Array BioPharma Inc.

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Drug and food interactions

Major

encorafenib food

Applies to: encorafenib

GENERALLY AVOID: Coadministration with potent or moderate inhibitors of CYP450 3A4 may significantly increase the plasma concentrations of encorafenib, which is primarily metabolized by the isoenzyme. When a single 50 mg dose of encorafenib (equivalent to 0.1 times the recommended dose) was administered with posaconazole, a potent CYP450 3A4 inhibitor, encorafenib peak plasma concentration (Cmax) increased by 68% and systemic exposure (AUC) increased by 3-fold. When the same dose of encorafenib was administered with diltiazem, a moderate CYP450 3A4 inhibitor, encorafenib Cmax increased by 45% and AUC increased by 2-fold. Increased exposure to encorafenib may increase the risk of serious and life-threatening adverse effects such as hemorrhage, uveitis, QT prolongation, hepatotoxicity, dermatologic reactions, and new malignancies.

MANAGEMENT: Concomitant use of encorafenib with grapefruit or grapefruit juice should generally be avoided. If coadministration is required, the manufacturer recommends reducing the encorafenib dose to one-third of the dose used prior to addition of a potent CYP450 3A4 inhibitor or one-half of the dose used prior to addition of a moderate CYP450 3A4 inhibitor. After the inhibitor has been discontinued for 3 to 5 elimination half-lives, the encorafenib dose that was taken prior to initiating the inhibitor may be resumed.

References

  1. (2018) "Product Information. Braftovi (encorafenib)." Array BioPharma Inc.

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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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