Which of the following is a reported side effect of varenicline?

• A. Abnormal dreams
• B. Hypoglycemia
• C. Weight gain of 50 pounds
• D. Visual hallucinations

Answer: (A)

Abnormal dreams are a commonly reported side effect of varenicline. Varenicline acts as a partial agonist at the alpha4β2 nicotinic receptors, which helps reduce withdrawal and craving but can also affect sleep-related neurotransmission. For many people, this manifests as vivid or unusual dreams in the course of treatment.

Hypoglycemia isn’t typically linked to varenicline, since it targets nicotine receptors rather than glucose regulation. A weight gain of 50 pounds is not a known or expected effect of this medication; smoking-cessation often leads to mixed weight changes but not such extreme gain from varenicline itself. Visual hallucinations are not common, though rare neuropsychiatric effects can occur; they are not the standard or most reported side effect.

So, the best answer is abnormal dreams because it is the classic and commonly observed sleep-related side effect of varenicline.