Dantrolene

Dantrolene

Dantrolene is a muscle relaxant that acts by suppressing calcium release from the sarcoplasmic reticulum in skeletal muscle. It is primarily used in the treatment of malignant hyperthermia, neuroleptic malignant syndrome, and other spastic muscular conditions.

Pharmacology

Dantrolene is a direct-acting skeletal muscle relaxant. It is unique among muscle relaxants in that it does not act at the neuromuscular junction or directly on muscle fibers. Instead, it acts by inhibiting calcium ion release from the sarcoplasmic reticulum in skeletal muscle, the structure that stores calcium ions. This action is mediated by the ryanodine receptor, the main calcium channel in the sarcoplasmic reticulum. Dantrolene's inhibition of calcium release leads to a decrease in muscle contraction and therefore a decrease in muscle spasticity.

Clinical Uses

Dantrolene is primarily used in the treatment of two life-threatening conditions, malignant hyperthermia and neuroleptic malignant syndrome. Both of these conditions are characterized by a rapid increase in body temperature and severe muscle contractions, and can be triggered by certain medications. Dantrolene is also used to treat muscle spasticity associated with conditions such as cerebral palsy, multiple sclerosis, and spinal cord injury.

Side Effects

The most common side effects of dantrolene include drowsiness, dizziness, weakness, and fatigue. Less common but more serious side effects can include liver damage, heart problems, and respiratory depression. Because of the risk of liver damage, dantrolene should be used with caution in patients with pre-existing liver disease.

History

Dantrolene was first synthesized in the 1960s and was initially used in the treatment of muscle spasticity. Its use in the treatment of malignant hyperthermia was first reported in the 1970s.

See Also

• Muscle relaxant
• Malignant hyperthermia
• Neuroleptic malignant syndrome
• Sarcoplasmic reticulum
• Ryanodine receptor