dantrolieni

Dantrolene is a skeletal muscle relaxant used to manage conditions characterized by excessive muscle contraction. It works by inhibiting calcium release from the sarcoplasmic reticulum in skeletal muscle cells, primarily through antagonism of the ryanodine receptor type 1 (RyR1). By lowering intracellular calcium during excitation–contraction coupling, dantrolene reduces muscle tone. The drug has minimal effects on smooth muscle and the central nervous system.

The primary indication is the treatment and prevention of malignant hyperthermia, a life-threatening pharmacogenetic reaction to certain anesthetics and depolarizing relaxants such as succinylcholine. For malignant hyperthermia, an intravenous form (dantrolene sodium) is administered emergently, with dosing commonly initiated around 2.5 mg/kg and repeated as needed up to a total dose near 10 mg/kg, guided by clinical response and cooling.

Dantrolene is also used orally for long-term management of severe spasticity resulting from conditions such as cerebral palsy, multiple sclerosis, or spinal cord injury, although the evidence for functional improvement varies and long-term use requires regular liver monitoring due to potential hepatotoxicity.

In some cases, dantrolene is employed as an adjunct in neuroleptic malignant syndrome, though its role is not universally accepted and treatment decisions are individualized.

Safety and adverse effects: the most significant risk is hepatotoxicity, which can be severe and increases with duration of therapy; liver function tests should be monitored. Other common adverse effects include drowsiness, dizziness, weakness, diarrhea, and flushing. The drug is poorly penetrant to the central nervous system and may interact with other hepatotoxic agents. It is contraindicated in significant hepatic impairment.