Drug Interactions between amphetamine and terbinafine

Consumer information for this interaction is not currently available.

MONITOR: Coadministration with inhibitors of CYP450 2D6 may increase the plasma concentrations as well as the pharmacologic and adverse effects of amphetamines (e.g., amphetamine, dextroamphetamine, methamphetamine). The proposed mechanism involves the inhibition of CYP450 2D6, an isoenzyme partially responsible for the metabolic clearance of certain amphetamines. Furthermore, because CYP450 2D6 is genetically polymorphic, variations in amphetamine metabolism across populations may either increase or decrease the risk associated with this interaction. Increased exposure to amphetamines may potentiate the risk of serious adverse reactions such as serotonin syndrome, seizures, psychiatric adverse reactions (e.g., new psychotic or manic symptoms), peripheral vasculopathy (including Raynaud's Phenomenon), and cardiovascular effects (e.g., hypertension, tachycardia). However, data evaluating the interaction are not available.

MANAGEMENT: Caution and closer monitoring for adverse effects are recommended when amphetamines are used concurrently with CYP450 2D6 inhibitors, and a reduction in the initial amphetamine dose should be considered. Patients should be more closely monitored for signs and symptoms of serotonin syndrome, particularly during the initiation of amphetamine therapy and following any dosage increases. Additional caution is advised when amphetamines are coadministered with CYP450 2D6 inhibitors that lower the seizure threshold (e.g., bupropion). Patients should be instructed to notify their healthcare provider if they experience increased amphetamine-related side effects, such as seizures, cardiovascular effects (e.g., hypertension, tachycardia), or symptoms of serotonin syndrome (e.g., mental status changes, autonomic dysfunction like tachycardia or hyperthermia, neuromuscular abnormalities such as hyperreflexia, or gastrointestinal symptoms).