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Drug Interactions between cobicistat / elvitegravir / emtricitabine / tenofovir and ifosfamide

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

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Interactions between your drugs

Major

ifosfamide tenofovir

Applies to: ifosfamide and cobicistat / elvitegravir / emtricitabine / tenofovir

Tenofovir may cause kidney problems, and combining it with other medications that can also affect the kidney such as ifosfamide may increase that risk. 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. You should seek immediate medical attention if you develop signs and symptoms that may suggest kidney damage such as nausea, vomiting, loss of appetite, increased or decreased urination, sudden weight gain or weight loss, fluid retention, swelling, shortness of breath, bone pain, muscle cramps, tiredness, weakness, dizziness, confusion, and irregular heart rhythm. 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.

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Moderate

tenofovir cobicistat

Applies to: cobicistat / elvitegravir / emtricitabine / tenofovir and cobicistat / elvitegravir / emtricitabine / tenofovir

Using cobicistat together with tenofovir can increase the effects of tenofovir, which can cause new or worse kidney problems. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Contact your doctor if your condition changes or you experience increased side effects. 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.

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Moderate

emtricitabine cobicistat

Applies to: cobicistat / elvitegravir / emtricitabine / tenofovir and cobicistat / elvitegravir / emtricitabine / tenofovir

Cobicistat is a medication used to boost the effects of some medications that treat HIV infection. However, using cobicistat together with other HIV medications, such as emtricitabine, may alter the blood levels and effects of both medications. Using emtricitabine with cobicistat may reduce or increase blood levels of cobicistat. Reduced blood levels of cobicistat may make cobicistat less effective and may cause overall HIV treatment to be less effective. Cobicistat may increase blood levels of emtricitabine which may increase the risk of side effects. Talk to your doctor or pharmacist if you have any questions on how to use these medications properly. 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. Contact your doctor if your condition changes or you experience increased side effects. 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.

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Drug and food interactions

Moderate

ifosfamide food

Applies to: ifosfamide

Consumer information for this interaction is not currently available.

GENERALLY AVOID: Grapefruit and/or grapefruit juice may reduce the efficacy of ifosfamide, whose anticancer effect is dependent on its activation to the 4-hydroxyifosfamide metabolite via CYP450 3A4. The proposed mechanism is inhibition of CYP450 3A4 metabolism by certain compounds present in grapefruit. There are no data available about the effects of grapefruit on ifosfamide. However, in a small study, 8 patients with incurable malignancies received ifosfamide 3 g/m2 by infusion with the potent CYP450 3A4 inhibitor ketoconazole 200 mg orally twice daily for 4 days starting 1 day before the ifosfamide infusion. Ketoconazole decreased the clearance of ifosfamide by 11%, decreased systemic exposure (AUC) of the active metabolite 4-hydroxyifosfamide by 30%, and increased the AUC of the inactive but potentially neurotoxic metabolite 2-dechloroethylifosfamide by 23%, as compared to control. Because pharmacokinetic interactions involving grapefruit juice are often subject to a high degree of interpatient variability, the extent to which a given patient may be affected is difficult to predict.

GENERALLY AVOID: Alcohol may potentiate the neurotoxic effects of ifosfamide. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills. In addition, ifosfamide therapy may cause gastrointestinal disorders and alcohol consumption may increase nausea and vomiting.

MANAGEMENT: Given the potential for reduced efficacy of ifosfamide and increased risk of neurotoxicity and nephrotoxicity it may be advisable for patients to avoid consumption of grapefruit, grapefruit juice, or supplements that contain grapefruit during treatment with ifosfamide. In addition, patients receiving ifosfamide should be warned of the increased risk of neurotoxicity, nausea and vomiting when used in combination with alcohol. Patients should avoid or limit the consumption of alcohol during treatment with ifosfamide.

References

  1. "Product Information. Ifosfamide (ifosfamide)." Hikma USA (formerly West-Ward Pharmaceutical Corporation) (2019):
  2. Kerbusch T, jansen rlh, mathot raa, huitema adr, Jansen RNM, Rijswijk REN, Beijen JH "Modulation of the cytochrome P450-mediated metabolism of ifosfamide by ketoconazole and rifampin" Clin Pharmacol and Therapeutic 70 (2001): 132-141
  3. "Product Information. Ifex (ifosfamide)." Baxter Pharmaceutical Products, Inc (2018):
  4. "Product Information. Holoxan (iFOSFamide)." Baxter Healthcare Pty Ltd (2018):
  5. "Product Information. Ifosfamide (ifosfamide)." Baxter Healthcare Ltd (2022):
  6. "Product Information. Ifex (ifosfamide)." Baxter Corporation (2018):
View all 6 references
Moderate

elvitegravir food

Applies to: cobicistat / elvitegravir / emtricitabine / tenofovir

Food significantly increases the absorption of elvitegravir. You should take each dose of elvitegravir with a meal. Taking it on an empty stomach may lead to inadequate blood levels and reduced effectiveness of the medication in treating HIV infection.

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Minor

tenofovir food

Applies to: cobicistat / elvitegravir / emtricitabine / tenofovir

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.

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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