Outline the pharmacology of dantrolene.
Dantrolene is an intracellular muscle relaxant. It works by reducing intracellular calcium concentrations. This may result from impaired release from the sarcoplasmic reticu-lum or inhibition of excitation–contraction coupling. As of this writing, dantrolene is the only mechanism-specific treatment for MH.
Dantrolene does not appear to possess cardiac toxicity but may alter other neuromuscular blocker requirements. After administration of dantrolene 2.5 mg/kg intra-venously, therapeutic levels last 4–6 hours. Its half-life is almost 12 hours. Consequently, dantrolene is administered every 4 hours for the treatment of MH. Muscle weakness, nausea, hepatotoxicity, and phlebitis are the recognized side-effects of dantrolene treatment.