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Drug Interactions between Felbatol and fosphenytoin

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

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Interactions between your drugs

Moderate

felbamate fosphenytoin

Applies to: Felbatol (felbamate) and fosphenytoin

ADJUST DOSE: Felbamate may increase steady-state plasma concentrations of phenytoin by decreasing its plasma clearance. Also, phenytoin may increase (and may nearly double) the plasma clearance of felbamate. Other hydantoins may interact with felbamate in a similar manner.

MANAGEMENT: When combination therapy is started, felbamate should be initiated at 1200 mg per day in 3 to 4 divided doses while reducing the phenytoin dose by 20% to 40%. In general, the felbamate dose may be titrated more quickly than when felbamate is given as monotherapy. Close observation for clinical and laboratory evidence of altered effects is indicated. Patients should be advised to notify their physician if they experience symptoms of toxicity, including drowsiness, visual disturbances, change in mental status, seizures, nausea, or ataxia.

References (4)
  1. Wagner ML, Graves NM, Marienau K, Holmes GB, Remmel RP, Leppik IE (1991) "Discontinuation of phenytoin and carbamazepine in patients receiving felbamate." Epilepsia, 32, p. 398-406
  2. Graves NM, Holmes GB, Fuerst RH, Leppik IE (1989) "Effect of felbamate on phenytoin and carbamazepine serum concentrations." Epilepsia, 30, p. 225-9
  3. Fuerst RH, Graves NM, Leppik IE, Brundage RC, Holmes GB, Remmel RP (1988) "Felbamate increases phenytoin but decreases carbamazepine concentrations." Epilepsia, 29, p. 488-91
  4. (2001) "Product Information. Felbatol (felbamate)." Wallace Laboratories

Drug and food interactions

Moderate

felbamate food

Applies to: Felbatol (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 (4)
  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

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.

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