Drug Interaction Report

MONITOR: Coadministration of L-arginine or L-citrulline may potentiate the hypotensive effects of nitrates and vasodilators. Both L-arginine and L-citrulline are amino acid precursors to nitric oxide, which causes vasodilation and increased blood flow.

MANAGEMENT: Due to potentially additive effects in the vasculature, caution is advised during concomitant use of L-arginine or L-citrulline with nitrates and vasodilators. Blood pressure and heart rate should be closely monitored.

GENERALLY AVOID: The concurrent use of ethanol and alpha-1 adrenergic blockers may cause increased hypotensive effects. Patients with aldehyde dehydrogenase deficiencies (primarily Asians) may be at a higher risk of this interaction. The mechanism has not been determined. Data exist for prazosin and other alpha adrenergic blockers are expected to interact also. In addition, any patients taking alpha adrenergic blockers may experience excessive orthostatic hypotension with ethanol ingestion, due to ethanol's unopposed vasodilatory effects in the presence of alpha adrenergic blockade.

MANAGEMENT: Patients who develop a flushing reaction after ethanol ingestion (indicates a possible aldehyde dehydrogenase deficiency) should be advised to avoid ethanol or limit their intake. All patients should be warned about the possibility of orthostatic hypotension with concurrent ethanol use.