MH DRILL In a malignant hyperthermia emergency, the sooner you start treatment after you make a diagnosis, the better.

MALIGNANT HYPERTHERMIA Is the Convenience Of a New MH Antidote Worth the Cost?

A new formulation of dantrolene called Ryanodex (Eagle Pharmaceuticals) lets you get much more antidote into the patient much faster during a malignant hyperthermia crisis, but it’s unknown whether a bigger, faster loading dose of dantrolene is clinically helpful.

Just 1 vial of Ryanodex provides a loading dose (2.5 mg/kg) of dantrolene sodium for most patients. The company says Ryanodex can be prepared and administered in less than 1 minute, compared with 15 to 20 minutes for conventional dantrolene, which requires multiple 20 mg vials, each reconstituted in 60 mL of sterile water. Each vial of Ryanodex contains 250 mg of dantrolene sodium and requires reconstitution with only 5 mL of sterile water for injection. Once you have the first vial of Revonto or Dantrium reconstituted, you can begin administering the antidote, but for an adult patient, you’ll need to keep mixing and reconstituting — 8 or 10 or 12 more vials — to keep it flowing.

But you’ll pay for the convenience Ryanodex provides. As you’ll see in the table below, Ryanodex costs more than twice as much as, and has a shorter shelf life than, Revonto (US WorldMeds) and Dantrium (Par Pharmaceutical).

Regardless of which antidote you stock, chances are you’ll never use it. The overwhelming odds are that you’ll never experience an episode of MH, an inherited and potentially fatal disorder triggered by certain anesthesia agents in genetically susceptible individuals. Experts say you should use expired product in MH-preparedness staff drills.

— Jim Burger