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Drug Interactions between Rimactane and ulipristal

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

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Interactions between your drugs

Major

rifAMPin ulipristal

Applies to: Rimactane (rifampin) and ulipristal

GENERALLY AVOID: Coadministration with potent and moderate inducers of CYP450 3A4 may significantly decrease the plasma concentrations of ulipristal acetate and its pharmacologically active metabolite. Based on in vitro and pharmacokinetic data, ulipristal acetate is thought to be primarily metabolized by CYP450 3A4 to mono-demethylated and di-demethylated metabolites. When a single 30 mg dose of ulipristal acetate was administered following a 9-day treatment with 600 mg once daily of rifampin, a potent CYP450 3A4 inducer, ulipristal acetate peak plasma concentration (Cmax) and systemic exposure (AUC) decreased by 90% and 93% respectively, while half-life decreased by 2.2-fold. The Cmax and AUC of monodemethyl-ulipristal acetate, the active metabolite, decreased by 84% and 90%, respectively. The interaction has not been studied with other, less potent inducers.

MANAGEMENT: Concomitant use of ulipristal acetate with potent and moderate CYP450 3A4 inducers should generally be avoided due to the potential for loss of therapeutic efficacy. For patients who have used enzyme-inducing drugs within the past 4 weeks and are seeking emergency contraception, ulipristal acetate is not recommended and a non-hormonal method (i.e. a copper intrauterine device (Cu-IUD)) should be considered.

References

  1. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  2. Cerner Multum, Inc. "Australian Product Information." O 0
  3. "Product Information. Ella (ulipristal)." Afaxys Inc. (2022):
  4. Cerner Multum, Inc. "Canadian Product Information." O 0 (2015):
  5. "Product Information. Esmya (ulipristal)." Gedeon Richter (UK) Ltd (2021):
  6. "Product Information. EllaOne (ulipristal)." HRA Pharma UK & Ireland Ltd (2021):
View all 6 references

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Drug and food interactions

Moderate

rifAMPin food

Applies to: Rimactane (rifampin)

GENERALLY AVOID: Concurrent use of rifampin in patients who ingest alcohol daily may result in an increased incidence of hepatotoxicity. The increase in hepatotoxicity may be due to an additive risk as both alcohol and rifampin are individually associated with this adverse reaction. However, the exact mechanism has not been established.

ADJUST DOSING INTERVAL: Administration with food may reduce oral rifampin absorption, increasing the risk of therapeutic failure or resistance. In a randomized, four-period crossover phase I study of 14 healthy male and female volunteers, the pharmacokinetics of single dose rifampin 600 mg were evaluated under fasting conditions and with a high-fat meal. Researchers observed that administration of rifampin with a high-fat meal reduced rifampin peak plasma concentration (Cmax) by 36%, nearly doubled the time to reach peak plasma concentration (Tmax) but reduced overall exposure (AUC) by only 6%.

MANAGEMENT: The manufacturer of oral forms of rifampin recommends administration on an empty stomach, 30 minutes before or 2 hours after meals. Patients should be encouraged to avoid alcohol or strictly limit their intake. Patients who use alcohol and rifampin concurrently or have a history of alcohol use disorder may require additional monitoring of their liver function during treatment with rifampin.

References

  1. "Product Information. Rifampin (rifAMPin)." Akorn Inc (2022):
  2. "Product Information. Rifampicin (rifampicin)." Mylan Pharmaceuticals Inc (2022):
  3. "Product Information. Rifadin (rifampicin)." Sanofi (2023):
  4. "Product Information. Rifadin (rifaMPICin)." Sanofi-Aventis Australia Pty Ltd (2024):
  5. Peloquin CA, Namdar R, Singleton MD, Nix DE "Pharmacokinetics of rifampin under fasting conditions, with food, and with antacids https://pubmed.ncbi.nlm.nih.gov/9925057/" (2024):
  6. "Product Information. Rofact (rifampin)." Bausch Health, Canada Inc. (2019):
View all 6 references

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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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