Co-administration of dantrolene and verapamil intravenously increases the risk of which complication?

Co-administration of dantrolene and verapamil intravenously increases the risk of which complication?

• A. Hyperkalemia
• B. Constipation
• C. Hepatotoxicity
• D. Profound muscular weakness

Answer: (A)

Co-administration of dantrolene and verapamil intravenously increases the risk of hyperkalemia because both drugs disrupt calcium handling in muscle and cardiac cells, which can lead to potassium leaking out of cells. Dantrolene blocks calcium release from the sarcoplasmic reticulum by inhibiting the ryanodine receptor, reducing muscle contraction. Verapamil, a calcium channel blocker, reduces calcium entry into cells via L-type channels. When used together, these opposing effects on calcium dynamics can destabilize cell membranes and overwhelm the cells’ ability to regulate intracellular potassium, causing potassium to spill into the bloodstream. Elevated potassium can then provoke dangerous cardiac arrhythmias, making hyperkalemia the most clinically relevant risk with this combination. The other options are less directly tied to this interaction: profound muscular weakness is mainly a direct effect of dantrolene, hepatotoxicity is a known long-term risk of dantrolene, and constipation is unrelated to this drug interaction.

Co-administration of dantrolene and verapamil intravenously increases the risk of hyperkalemia because both drugs disrupt calcium handling in muscle and cardiac cells, which can lead to potassium leaking out of cells. Dantrolene blocks calcium release from the sarcoplasmic reticulum by inhibiting the ryanodine receptor, reducing muscle contraction. Verapamil, a calcium channel blocker, reduces calcium entry into cells via L-type channels. When used together, these opposing effects on calcium dynamics can destabilize cell membranes and overwhelm the cells’ ability to regulate intracellular potassium, causing potassium to spill into the bloodstream. Elevated potassium can then provoke dangerous cardiac arrhythmias, making hyperkalemia the most clinically relevant risk with this combination. The other options are less directly tied to this interaction: profound muscular weakness is mainly a direct effect of dantrolene, hepatotoxicity is a known long-term risk of dantrolene, and constipation is unrelated to this drug interaction.