Drug Interactions between mepenzolate and nebivolol

MONITOR: Anticholinergic agents frequently cause drowsiness and other central nervous system-depressant effects that may be additive with those induced by beta blockers. In addition, these agents may increase heart rate and theoretically may counteract the bradycardic effects of beta blockers. Pharmacokinetically, anticholinergic agents may delay the gastrointestinal absorption of beta blockers and other drugs that are administered orally. The proposed mechanism involves increased gastrointestinal transit time due to reduction of stomach and intestinal motility by anticholinergic agents. In healthy volunteers, pretreatment with propantheline has been shown to prolong the time to reach peak plasma concentration (Tmax) for both atenolol and metoprolol. Propantheline also decreased metoprolol peak plasma concentration (Cmax) but had no effect on its systemic exposure (AUC). In contrast, propantheline increased atenolol AUC but had no effect on its Cmax. The clinical relevance of these changes is probably minimal.

MANAGEMENT: Clinicians should be aware of the potential for diminished effects of beta blockers during coadministration with anticholinergic agents. Patients should also be monitored for potentially excessive CNS adverse effects (e.g., drowsiness, dizziness, lightheadedness, confusion, blurred vision) if these agents are used in combination. Patients should be counseled to avoid activities requiring mental alertness until they know how these agents affect them.