Which of the following is NOT a symptom of cholinesterase inhibition?

• A. Headache, dizziness, nausea, muscle twitching, pinpoint pupils, and drooling
• B. Weight gain
• C. Nausea
• D. Dizziness

Answer: (B)

Cholinesterase inhibitors cause an excess of acetylcholine, leading to overstimulation of muscarinic and nicotinic receptors and a cholinergic syndrome. The listed symptoms—headache, dizziness, nausea, muscle twitching, pinpoint pupils, and drooling—reflect this increased acetylcholine activity: central effects like headache and dizziness, gastrointestinal upset like nausea, muscle fasciculations from nicotinic stimulation, miosis from muscarinic effects, and excessive secretions such as drooling. Nausea and dizziness are common, nonspecific signs that fit the pattern of cholinesterase inhibition. Weight gain, however, is not part of the acute cholinergic picture and isn’t caused by this inhibition in exposure scenarios. Therefore, weight gain is the correct choice.