Drug Interaction Report

MONITOR: Use of anticholinergic drugs after administration of botulinum toxin may potentiate systemic anticholinergic effects such as dry mouth, blurred vision, and urinary disorders. Botulinum toxin inhibits the release of acetylcholine from peripheral cholinergic nerve endings, thus additive or synergistic anticholinergic effects may occur when these agents are used together.

MANAGEMENT: Patients should be advised that systemic anticholinergic side effects such as dry mouth, blurred vision, and urinary disorders may increase if agents with anticholinergic properties (e.g., sedating antihistamines; antispasmodics; neuroleptics; phenothiazines; skeletal muscle relaxants; tricyclic antidepressants; disopyramide) are used after administration of botulinum toxin.

ADJUST DOSING INTERVAL: Food may reduce the oral absorption and bioavailability of trospium chloride. According to the product labeling, administration of trospium chloride with a high fat meal reduced the peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) by 70% to 80% compared to administration while fasting.

MANAGEMENT: To ensure maximal oral absorption, trospium chloride should be administered at least 1 hour before meals or on an empty stomach. If trospium chloride is administered as a combination with xanomeline, the manufacturer recommends administering the capsules at least 1 hour before a meal or at least 2 hours after a meal. Capsules should be taken whole.