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Drug Interactions between felbamate and rifapentine

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

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Interactions between your drugs

Moderate

felbamate rifapentine

Applies to: felbamate and rifapentine

MONITOR: Coadministration with potent CYP450 3A4 inducers may decrease the plasma concentrations of felbamate, which may be a substrate of the isoenzyme. Pharmacokinetic data may not be available for all potent inducers with respect to their effect on felbamate. However, the potent CYP450 3A4 inducers carbamazepine, phenobarbital, and phenytoin have all been shown to decrease felbamate plasma concentrations. Felbamate steady-state trough concentrations have decreased by approximately 40% and 45% when administered with carbamazepine and phenytoin, respectively, compared to the same dose of felbamate monotherapy. In addition, concomitant use of phenobarbital resulted in a 29% decrease in felbamate steady-state plasma concentrations as compared to felbamate monotherapy.

MANAGEMENT: Caution is advised if felbamate is used concomitantly with potent CYP450 3A4 inducers. Dosage adjustments as well as clinical and laboratory monitoring should be considered whenever a potent CYP450 3A4 inducer is added to or withdrawn from therapy with felbamate.

References

  1. (2002) "Product Information. Tegretol (carbamazepine)." Novartis Pharmaceuticals
  2. (2001) "Product Information. Rifadin (rifampin)." Hoechst Marion Roussel
  3. (2001) "Product Information. Phenobarbital (phenobarbital)." Lilly, Eli and Company
  4. (2001) "Product Information. Felbatol (felbamate)." Wallace Laboratories
  5. (2001) "Product Information. Dilantin (phenytoin)." Parke-Davis
  6. (2001) "Product Information. Rifamate (rifampin)." Hoechst Marion Roussel
  7. (2001) "Product Information. Carbatrol (carbamazepine)." Athena Neurosciences Inc
  8. Glue P, Banfield CR, Perhach JL, Mather GG, Racha JK, Levy RH (1997) "Pharmacokinetic interactions with felbamate.In vitro-in vivo correlation." Clin Pharmacokinet, 33, p. 214-24
View all 8 references

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Drug and food interactions

Moderate

felbamate food

Applies to: felbamate

GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of CNS-active agents. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

MANAGEMENT: Patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

References

  1. Warrington SJ, Ankier SI, Turner P (1986) "Evaluation of possible interactions between ethanol and trazodone or amitriptyline." Neuropsychobiology, 15, p. 31-7
  2. Gilman AG, eds., Nies AS, Rall TW, Taylor P (1990) "Goodman and Gilman's the Pharmacological Basis of Therapeutics." New York, NY: Pergamon Press Inc.
  3. (2012) "Product Information. Fycompa (perampanel)." Eisai Inc
  4. (2015) "Product Information. Rexulti (brexpiprazole)." Otsuka American Pharmaceuticals Inc
View all 4 references

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Moderate

rifapentine food

Applies to: rifapentine

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

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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.


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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.