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Drug Interactions between Estratab and rifapentine

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

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Interactions between your drugs

Major

esterified estrogens rifapentine

Applies to: Estratab (esterified estrogens) and rifapentine

Consumer information for this interaction is not currently available.

MONITOR CLOSELY: Coadministration with rifampin or other rifamycins may reduce the efficacy of estrogen and progestin hormones that are CYP450 3A4 substrates. The interaction stems from accelerated clearance of the hormone(s) as well as decreased plasma concentrations of unbound (active) hormone(s) due to induction of CYP450 enzymatic activity and hormone-binding globulin capacity by rifampin and to a lesser extent with other rifamycins. In a study of 28 healthy premenopausal women on a combination oral contraceptive pill, coadministration with rifampin (300 mg/day for 10 days) reduced ethinyl estradiol peak plasma concentration (Cmax) and systemic exposure (AUC) by 42% and 64%, respectively, while the same dosage of rifabutin reduced ethinyl estradiol Cmax and AUC by 20% and 35%, respectively. Norethindrone AUC was reduced by 60% with rifampin and 20% with rifabutin. In addition, FSH and LH levels increased following rifamycin therapy, and the incidence of spotting was significantly higher after coadministration with rifampin (36.4%) and rifabutin (21.7%) than during the control cycle (3.7%). This interaction is not thought to be clinically relevant for persons using the progestin-only (DMPA) injection (as serum progestin levels are expected to remain adequate), locally acting levonorgestrel-releasing intrauterine systems (as the local effect on the endometrium is unaffected by enzyme induction), and the non-hormonal copper intrauterine device for contraception. Similarly, this interaction may not be as significant for each hormone. A pharmacokinetic study (n=65) in postmenopausal women examined the effects of rifampin (600 mg/day) on the exposure of levonorgestrel (0.03 mg, n=13), norethindrone (0.35 mg, n=14), desogestrel (0.075 mg, n=12), dienogest (2 mg, n=12), and a combination of drospirenone and ethinyl estradiol (3 mg/0.03 mg, n=14). Bound and unbound hormone levels were reviewed. The largest decreases in AUC were observed for etonogestrel (desogestrel's active metabolite), dienogest, and drospirenone at >80%. Levonorgestrel, norethindrone, and ethinyl estradiol had reductions in AUC between 50% and less than 80%.

MANAGEMENT: Caution and close clinical monitoring for reduced efficacy are advised for people using an estrogen and/or progestin-containing product for purposes other than contraception. These patients should be counseled to report any changes in efficacy of the hormonal product to their healthcare provider. Women using estrogens and/or progestins for contraception should be advised of the risk of breakthrough bleeding and unintended pregnancy during concomitant rifamycin therapy, even when given in short doses. Long-acting progestin-only injections and levonorgestrel-releasing intrauterine systems may be considered as alternative contraceptive agents. For the most current guidance, local relevant guidelines should be consulted. In general, alternative or additional methods of non-hormonal birth control should be used during and for at least 28 days after rifamycin therapy.

The following apply only to the specific medications (combined oral contraception) or situations (emergency contraception) specified:

-If a combination oral contraceptive pill is chosen despite the risks, a regimen containing at least 30 mcg of ethinyl estradiol per day or equivalent should be selected. Some authorities have suggested increasing to 50 mcg of ethinyl estradiol or equivalent; however, they recommend advising the patient that contraceptive effectiveness, even at this dose, may be reduced and that there could be an increased risk of thrombosis if exposure to ethinyl estradiol is increased.

-For emergency contraception in patients who have used a hepatic enzyme inducer in the past 4 weeks, a non-hormonal emergency contraceptive (e.g., copper intrauterine device) is considered preferable. If this is not possible, some authorities recommend that the usual dose of levonorgestrel (1.5 mg) be doubled to 3 mg and taken as a single dose as soon as possible (typically within 72 hours, though some guidelines suggest up to 96 hours, of unprotected sexual intercourse). However, the efficacy of this regimen is unknown.

References

  1. Venkatesan K "Pharmacokinetic drug interactions with rifampicin." Clin Pharmacokinet 22 (1992): 47-65
  2. Borcherding SM, Baciewicz AM, Self TH "Update on rifampin drug interactions." Arch Intern Med 152 (1992): 711-6
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  4. Joshi JV, Joshi UM, Sankolli GM, et al. "A study of interaction of a low-dose combination oral contraceptive with anti-tubercular drugs." Contraception 21 (1980): 617-29
  5. Bint AJ, Burtt I "Adverse antibiotic drug interactions." Drugs 20 (1980): 57-68
  6. Skolnick JL, Stoler BS, Katz DB, Anderson WH "Rifampin, oral contraceptives, and pregnancy." JAMA 236 (1976): 1382
  7. Dossetor J "Drug interactions with oral contraceptives." Br Med J 4 (1975): 467-8
  8. "Product Information. Mycobutin (rifabutin)." Pharmacia and Upjohn PROD (2001):
  9. "Product Information. Rifadin (rifampin)." Hoechst Marion Roussel PROD (2001):
  10. Baciewicz AM, Self TH "Rifampin drug interactions." Arch Intern Med 144 (1984): 1667-71
  11. Nocke-finck L "Effects of rifampicin on menstral cycle and on estrogen excretion in patients taking oral contraceptives." JAMA 226 (1973): 378
  12. Bolt HM, Bolt M, Kappus H "Interaction of rifampicin treatment with pharmacokinetics and metabolism of ethinyloestradiol in man." Acta Endocrinol (Copenh) 85 (1977): 189-97
  13. Back DJ, Breckenridge AM, Crawford FE, et al. "The effect of rifampicin on the pharmacokinetics of ethynylestradiol in women." Contraception 21 (1980): 135-43
  14. Back DJ, Breckenridge AM, Crawford F, et al. "The effect of rifampicin on norethisterone pharmacokinetics." Eur J Clin Pharmacol 15 (1979): 193-7
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  22. LeBel M, Masson E, Guilbert E, Colborn D, Paquet F, Allard S, Vallee F, Narang PK "Effects of rifabutin and rifampicin on the pharmacokinetics of ethinylestradiol and norethindrone." J Clin Pharmacol 38 (1998): 1042-50
  23. Barditch-Crovo P, Trapnell CB, Ette E, et al. "The effects of rifampin and rifabutin on the pharmacokinetics and pharmacodynamics of a combination oral contraceptive." Clin Pharmacol Ther 65 (1999): 428-38
  24. Weisberg E "Interactions between oral contraceptives and antifungals antibacterials - Is contraceptive failure the result?." Clin Pharmacokinet 36 (1999): 309-13
  25. Weaver K, Glasier A "Interaction between broad-spectrum antibiotics and the combined oral contraceptive pill: a literature review." Contraception 59 (1999): 71-8
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  31. Bounds W, Guillebaud J "Observational series on women using the contraceptive Mirena concurrently with anti-epileptic and other enzyme-inducing drugs." J Fam Plann Reprod Health Care 28 (2002): 78-80
  32. Faculty of Sexual & Reproductive Healthcare "FSRH Clinical Guidance: Drug Interactions with Hormonal Contraception. file:///C:/Users/df033684/Downloads/ceuguidancedruginteractionshormonal.pdf" (2016):
  33. Curtis KM, Tepper NK, Jatlaoui TC, et al. "U.S. medical eligibility criteria (US MEC) for contraceptive use. https://www.cdc.gov/reproductivehealth/contraception/mmwr/mec/index.html" (2023):
  34. Faculty of Sexual & Reproductive Healthcare "FSRH CEU guidance: drug interactions with hormonal contraception (may 2022) https://www.fsrh.org/standards-and-guidance/documents/ceu-clinical-guidance-drug-interactions-with-hormonal/" (2023):
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  38. Macleods Pharmaceuticals Limited "Rifapentine 300 mg tablets (Macleods Pharmaceuticals Ltd), TB398. WHO-PQ recommended summary of product characteristics. https://extranet.who.int/prequal/sites/default/files/whopar_files/TB398part4v1.pdf" (2024):
  39. Wiesinger H, Klein S, Rottmann A, et al. "The effects of weak and strong CYP3A induction by rifampicin on the pharmacokinetics of five progestins and ethinylestradiol compared to midazolam." Clin Pharmacol Ther 108 (2020): 798-807
View all 39 references

Drug and food interactions

Moderate

rifapentine food

Applies to: rifapentine

Consumer information for this interaction is not currently available.

ADJUST DOSING INTERVAL: Administration with food may increase the oral bioavailability of rifapentine and reduce the incidence of gastrointestinal adverse events. Administration with a high fat meal typically increases rifapentine's maximum concentration (Cmax) and systemic exposure (AUC) by approximately 40% to 50% over that observed when rifapentine is administered under fasting conditions. Rifapentine is often prescribed in combination with isoniazid. When single doses of rifapentine (900 mg) and isoniazid (900 mg) were administered with a low fat, high carbohydrate breakfast, the Cmax and AUC of rifapentine increased by 47% and 51%, respectively. On the other hand, isoniazid's Cmax and AUC decreased by 46% and 23%, respectively.

MANAGEMENT: Products containing oral rifapentine as the sole ingredient recommend administration with a meal to increase bioavailability and reduce the occurrence of gastrointestinal upset, nausea, and/or vomiting. Consultation of product labeling for combination products and/or relevant guidelines may be helpful if rifapentine is combined with a medication that is typically taken on an empty stomach.

References

  1. "Product Information. Isoniazid/Rifapentine 300 mg/300 mg (Macleods) (isoniazid-rifapentine)." Imported (India) 2 (2021):
  2. "Product Information. Priftin (rifapentine)." sanofi-aventis (2021):
Minor

esterified estrogens food

Applies to: Estratab (esterified estrogens)

Information for this minor interaction is available on the professional version.

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.


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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.