Drug Interaction Report

MONITOR: The use of amifampridine is associated with a dose-related risk of seizures, and the risk may be further increased when coadministered with other drugs that can reduce the seizure threshold such as antidepressants, antimalarials, neuroleptics, phenothiazines, and quinolones. Seizures have occurred in patients without a history of seizures taking amifampridine at recommended dosages and at various times after initiation of treatment. Reported incidence is approximately 2%. Many of the patients were taking medications or had comorbid medical conditions that may have lowered the seizure threshold.

MANAGEMENT: Caution is advised if amifampridine is coadministered with any substance that can reduce the seizure threshold, particularly in the elderly and in patients with other risk factors for seizures (e.g., head trauma; brain tumor; severe hepatic cirrhosis; metabolic disorders; CNS infections; excessive use of alcohol or sedatives; addiction to opiates, cocaine, or stimulants; diabetes treated with oral hypoglycemic agents or insulin). Consider discontinuation or dose reduction of amifampridine in patients who experience a seizure during treatment. Use of amifampridine is contraindicated in patients with a history of seizures.

ADJUST DOSING INTERVAL: Food may reduce the oral absorption and bioavailability of levofloxacin. According to the drug product labeling, administration of levofloxacin 500 mg with food prolonged the time to peak concentration by 1 hour and decreased the Cmax decreased by 25% following administration of the oral solution and by 14% following administration of the oral tablet.

MANAGEMENT: To ensure maximal and consistent oral absorption, levofloxacin oral solution should be taken at least one hour before or two hours after meals. For administration of the oral solution with continuous enteral nutrition, some experts recommend that the tube feeding should be interrupted for one hour before and two hours after the dose of levofloxacin. The oral tablets may be taken without regard to food.