Drug Interactions between Fareston and rifampin
This report displays the potential drug interactions for the following 2 drugs:
- Fareston (toremifene)
- rifampin
Interactions between your drugs
rifAMPin toremifene
Applies to: rifampin and Fareston (toremifene)
RifAMPin may significantly reduce the blood levels of toremifene, which may make the medication less effective in treating your cancer. Talk to your doctor if you have any questions or concerns. Your doctor may be able to prescribe alternatives that do not interact, or you may need a dose adjustment or more frequent monitoring to safely use both medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.
Drug and food interactions
rifAMPin food
Applies to: rifampin
Consumer information for this interaction is not currently available.
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
- "Product Information. Rifampin (rifAMPin)." Akorn Inc (2022):
- "Product Information. Rifampicin (rifampicin)." Mylan Pharmaceuticals Inc (2022):
- "Product Information. Rifadin (rifampicin)." Sanofi (2023):
- "Product Information. Rifadin (rifaMPICin)." Sanofi-Aventis Australia Pty Ltd (2024):
- 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):
- "Product Information. Rofact (rifampin)." Bausch Health, Canada Inc. (2019):
toremifene food
Applies to: Fareston (toremifene)
You should avoid drinking grapefruit juice during treatment with toremifene. Grapefruit juice may increase the blood levels of toremifene. This can make you more likely to develop side effects such as vaginal bleeding, blood clots, or an irregular heart rhythm that may be serious or life-threatening. Contact your doctor if you experience potential signs and symptoms of blood clots such as chest pain, shortness of breath, sudden loss of vision, and pain, redness or swelling your arms or legs. You should also seek immediate medical attention if you develop sudden dizziness, lightheadedness, fainting, or fast or pounding heartbeats during treatment with toremifene.
Talk to your doctor before using toremifene with soy products. There is some evidence that substances present in soy may stimulate breast tumor growth and interfere with the action of toremifene, although this has not been proven. Whether soy products are effective for hot flashes is also uncertain. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.
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
Drug Interaction Classification
Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit. | |
Moderately clinically significant. Usually avoid combinations; use it only under special circumstances. | |
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. | |
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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