A nurse should observe a client who is taking a calcium channel blocker for side effects, which include

• A. Hypertension
• B. Diplopia
• C. Weight loss
• D. Urinary retention

Answer: (B)

Calcium channel blockers can cause a range of adverse effects from their vasodilating and cardiac depressant actions. While dizziness, headache, flushing, edema, and bradycardia are common, occasional visual disturbances can occur, including diplopia (double vision). This symptom matters to monitor because it may reflect changes in ocular perfusion or drug effects on conduction and perfusion that warrant clinical attention, dose adjustment, or a change in therapy. The other options don’t fit typical side effects: hypertension would be unlikely since these drugs lower blood pressure; weight loss is not characteristic (these agents can cause edema and sometimes weight gain); urinary retention is not a typical effect of calcium channel blockers.