A calcium channel blocker has been ordered for a client. Which condition in the client's history is a contraindication to this medication?

• A. Hypokalemia
• B. Dysrhythmias
• C. Hypotension
• D. Increased intracranial pressure

Answer: (C)

Calcium channel blockers lower blood pressure by relaxing vascular smooth muscle and, depending on the agent, can slow conduction through the heart. Starting a CCB in a client who is already hypotensive risks a dangerous further drop in blood pressure and inadequate organ perfusion, so hypotension is the contraindication. Hypokalemia, dysrhythmias, and increased intracranial pressure do not inherently prevent CCB use in all cases, and in some situations CCBs can be indicated or used with caution. The key point is that existing low blood pressure makes initiating a calcium channel blocker unsafe.