Drug Interaction Report

MONITOR: Coadministration with drugs that are inhibitors of CYP450 1A2 may increase the plasma concentrations of ropinirole, which is metabolized by the isoenzyme. Ciprofloxacin (500 mg twice a day), a known inhibitor of CYP450 1A2, has been reported to increase the peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of ropinirole (2 mg three times a day) by an average of 60% and 84%, respectively, in 12 study subjects. The possibility of prolonged and/or increased pharmacologic effects of ropinirole should be considered.

MANAGEMENT: Pharmacologic response to ropinirole should be monitored more closely whenever a CYP450 1A2 inhibitor is added to or withdrawn from therapy, and the ropinirole dosage adjusted as necessary. Patients should be advised to contact their physician if they experience excessive adverse effects of ropinirole such as agitation, hallucinations, orthostasis, sedation, confusion, or increased dyskinesia, flushing, dry mouth, sweating, and heart rate.

ADJUST DOSING INTERVAL: Food enhances the oral absorption and bioavailability of ribavirin. Administration of a single oral dose of ribavirin following a high-fat meal delayed absorption (Tmax was doubled) but increased the mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) by up to 70% compared to administration in the fasting state.

MANAGEMENT: To ensure maximal oral absorption, ribavirin should be administered with or immediately after a meal.

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.