Dantrolene can be used to treat malignant hyperthermia owing to its action on calcium release. Which option lists the correct drug?

• A. Ethosuximide
• B. Nimodipine
• C. Biphosphonates
• D. Dantrolene

Answer: (D)

Controlling calcium release from the skeletal muscle sarcoplasmic reticulum is the key idea. Malignant hyperthermia happens when triggering agents cause uncontrolled calcium release through the ryanodine receptor, leading to sustained muscle contraction and a dangerous hypermetabolic state. Dantrolene directly blocks that calcium release, dampening excitation–contraction coupling, which lowers muscle rigidity, reduces heat production, and helps correct the metabolic disturbances. The other drugs listed don’t affect calcium release in skeletal muscle in the way malignant hyperthermia requires—ethosuximide treats absence seizures by blocking T-type calcium channels, nimodipine is a vascular calcium channel blocker for cerebral vasospasm, and bisphosphonates affect bone resorption.