Drug Interactions between disopyramide and rivastigmine

GENERALLY AVOID: Acetylcholinesterase inhibitors (e.g., donepezil, galantamine, benzgalantamine, physostigmine, rivastigmine, tacrine) may antagonize the effects of anticholinergic agents and other agents that rely partially on their anticholinergic activity for therapeutic effects (e.g., some antiparkinsonian and antiemetic/antivertigo agents; class IA antiarrhythmics). By inhibiting the metabolism of acetylcholine, more of the neurotransmitter may be available to compete at muscarinic receptors, the site of action of anticholinergic agents. Conversely, anticholinergic agents may negate the already small pharmacologic benefits of acetylcholinesterase inhibitors in the treatment of dementia. These agents may also adversely affect elderly patients in general. Clinically significant mental status changes associated with anticholinergic agents can range from mild cognitive impairment to delirium, and patients with Alzheimer's disease and other dementia are especially sensitive.

MANAGEMENT: Anticholinergic agents should generally be avoided in patients with Alzheimer's disease or other cognitive impairment, regardless of whether they are receiving an acetylcholinesterase inhibitor. For patients requiring treatment to counteract adverse effects of acetylcholinesterase inhibitor therapy (e.g., gastrointestinal intolerance, urinary problems), an agent without anticholinergic properties should be used whenever possible. Otherwise, a dosage reduction, slower titration, or even discontinuation of the acetylcholinesterase inhibitor should be considered. For patients who are already receiving an acetylcholinesterase inhibitor with anticholinergic agents, every attempt should be made to discontinue the latter or substitute them with less anticholinergic alternatives. Caution is required, however, since anticholinergic withdrawal may occur. Seizures have been reported following abrupt discontinuation of anticholinergics during acetylcholinesterase inhibitor therapy.