Description: Dantrolene is a muscle relaxant. It produces relaxation by affecting the contractile response of the skeletal muscle, by interfering with the release of calcium from the sarcoplasmic reticulum
Absorption: Slowly and almost completely absorbed from the GI tract after oral admin.
Distribution: Extensively bound to plasma proteins.
Metabolism: Mainly hepatically metabolised to the hydroxylated metabolites.
Excretion: Mainly excreted in the urine as metabolites with a small amount of unchanged dantrolene; some is excreted in the bile. Elimination half-life: about 9 hr.


This is indicated along with other supportive measures in controlling clinical spasticity resulting from upper motor neuron disorders, such as in stroke, cerebral palsy, or multiple sclerosis

This is also indicated, before and/or after surgery, to prevent malignant hyperthermia in patients susceptible for it.



How to use dantrolene:


Malignant hyperthermia:

Adult and pediatric dose: 2.5 mg/kg IV, starting approximately 75 minutes before anesthesia and infused for over 1 hour.  For oral doses, it is taken for 4 to 8 mg/kg/day in three or four divided doses for 1 to 2 days prior to surgery.

Chronic spasticity:


25 mg orally once daily for 7 days, then

25 mg three times a day for 7 days,  then

50 mg three times a day for 7 days, then

100 mg three times a day.


0.5 mg/kg orally once daily for 7 days, then

0.5 mg/kg three times a day for 7 days, then

1 mg/kg three times a day for 7 days, then

2 mg/kg three times a day.

  • Your doctor will perform blood tests to make sure you do not have conditions that would prevent you from safely using dantrolene.
  • Your doctor may occasionally change your dose to make sure you get the best results.
  • Do not take this medicine in larger or smaller amounts or for longer than recommended.
  • Take this medicine with a full glass of water. If you take dantrolene within 3 or 4 hours before surgery, use only enough water needed to swallow the pill.

While using dantrolene, you may need frequent blood tests to check your liver function.

Liver disorder: It is important to recognize that fatal and non-fatal liver disorders of an idiosyncratic or hypersensitivity type may occur with Dantrolene sodium therapy.  It is desirable to do liver function studies (SGOT, SGPT, alkaline phosphatase, total bilirubin) for a baseline or to establish whether there is pre-existing liver disease. If baseline liver abnormalities exist and are confirmed, there is a clear possibility that the potential for Dantrolene sodium hepatotoxicity could be enhanced, although such a possibility has not yet been established.

Females over 35 years: Dantrolene sodium should be used with particular caution in females and in patients over 35 years of age in view of apparent greater likelihood of drug-induced, potentially fatal, hepatocellular disease in these groups.

The most frequently occurring side effects of Dantrolene sodium have been:

  • drowsiness,
  • dizziness,
  • weakness,
  • general malaise,
  • fatigue, and
  • diarrhea

Other less frequent side effects, listed according to system, are:

Gastrointestinal: Constipation, rarely progressing to signs of intestinal obstruction, GI bleeding, anorexia, swallowing difficulty, gastric irritation, abdominal cramps, nausea and/or vomiting.


  • Pleural effusion: Dantrolene sodium should be used with caution in patients with impaired pulmonary function, particularly those with obstructive pulmonary disease, and in patients with severely impaired cardiac function due to myocardial disease. Datrolene sodium is associated with pleural effusion with associated eosinophilia.
  • Hepatotoxicity: It should be used with caution in patients with a history of previous liver disease or dysfunction. It may lead to symptomatic hepatitis and fatal or non-fatal liver disease.

Pregnancy Risk:  Category C. Dantrolene should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Breastfeeding: Should be used by nursing mothers only if the potential benefit justifies the potential risk to the infant.


  • Drowsiness may occur with Dantrolene sodium therapy, and the concomitant administration of CNS depressants such as sedatives and tranquilizing agents may result in further drowsiness.
  • Hepatotoxicity has occurred more often in women over 35 years of age receiving concomitant estrogen therapy.
  • The combination of therapeutic doses of intravenous Dantrolene sodium and verapamil in halothane/α-chloralose anesthetized swine has resulted in ventricular fibrillation and cardiovascular collapse in association with marked hyperkalemia.
  • Administration of Dantrolene sodium may potentiate vecuronium-induced neuromuscular block.


Symptoms which may occur in case of overdose include, but are not limited to, muscular weakness and alterations in the state of consciousness (e.g. lethargy, coma), vomiting, diarrhea, and crystalluria. For acute overdose, general supportive measures should be employed along with immediate gastric lavage.

Intravenous fluids should be administered in fairly large quantities to avert the possibility of crystalluria. An adequate airway should be maintained and artificial resuscitation equipment should be at hand. Electrocardiographic monitoring should be instituted, and the patient carefully observed. To date, no experience has been reported with dialysis and its value in Dantrolene sodium overdose is not known.


There are no brands containing this molecule.

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