A patient presents with hypotension and bradycardia. Which medication is most likely contributing to these symptoms?

Donepezil is an acetylcholinesterase inhibitor commonly used to treat Alzheimer's disease. Its mechanism enhances cholinergic activity by increasing the levels of acetylcholine in the synaptic cleft. While this can improve cognitive function in some patients, it can also lead to several side effects, particularly in relation to the cardiovascular system.

One significant consequence of increased acetylcholine is increased vagal tone, which can result in bradycardia (a slower-than-normal heart rate). The stimulation of the parasympathetic nervous system by acetylcholine can lead to a decrease in heart rate and, consequently, may contribute to hypotension due to reduced cardiac output. These pharmacological effects align well with the symptoms of hypotension and bradycardia experienced by the patient.

Venlafaxine, a serotonin-norepinephrine reuptake inhibitor, is unlikely to cause significant bradycardia and hypotension in the same manner due to its different pharmacological profile. Ginseng is considered an herbal supplement with various effects, but it does not typically lead to the serious cardiovascular effects seen with donepezil. Memantine, being an NMDA receptor antagonist, primarily affects glutamatergic neurotransmission and is also less associated with