Dantrolene
Dantrolene is used to help relax certain muscles in your body. It relieves the spasms, cramping, and tightness of muscles caused by certain medical problems such as multiple sclerosis (MS), cerebral palsy, stroke, or injury to the spine. Dantrolene does not cure these problems, but it may allow other treatment, such as physical therapy, to be more helpful in improving your condition. Dantrolene acts directly on the muscles to produce its relaxant effects.
Dantrolene is also used to prevent or treat a medical problem called malignant hyperthermia that may occur in some patients during or following surgery or anesthesia.
Mechanism of effect
Dantrolene depresses excitation-contraction coupling in skeletal muscle by acting as a receptor antagonist to the ryanodine receptor, and decreasing free intracellular calcium concentration. Ryanodine receptors mediate the release of calcium from the sarcoplasmic reticulum, an essential step in muscle contraction.
Pharmacodynamic
Dantrolene is classified as a direct-acting skeletal muscle relaxant. It is currently the only specific and effective treatment for malignant hyperthermia.
Pharmacokinetics
Dantrolene Bioavailability is 70%. The mean biologic half-life after intravenous administration is variable, between 4 to 8 hours under most experimental conditions, while oral is 8.7 hours for a 100mg dose. Route of elimination is not available.
Dosage
- Usual Adult Dose for Malignant Hyperthermia
For preoperative to prevent or attenuate the development of clinical and laboratory signs of malignant hyperthermia in individuals judged to be susceptible:
IV: 2.5 mg/kg IV, starting approximately 75 minutes before anticipated anesthesia and infused over approximately 1 hour.
Oral: 4 to 8 mg/kg/day orally in three or four divided doses for 1 or 2 days prior to surgery, with the last dose being given with a minimum of water approximately 3 to 4 hours before scheduled surgery.
For postoperative use to prevent or attenuate the recurrence of signs of malignant hyperthermia when oral administration is not practical:
IV: dose must be individualized, starting with 1 mg/kg or more as the clinical situation dictates.
- Usual Adult Dose for Chronic Spasticity
For use in controlling the manifestations of clinical spasticity resulting from upper motor neuron disorders:
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.
Usual Pediatric Dose for Malignant Hyperthermia
For preoperative to prevent or attenuate the development of clinical and laboratory signs of malignant hyperthermia in individuals judged to be susceptible:
IV: 2.5 mg/kg IV, starting approximately 75 minutes before anticipated anesthesia and infused over approximately 1 hour.
Oral: 4 to 8 mg/kg/day orally in three or four divided doses for 1 or 2 days prior to surgery, with the last dose being given with a minimum of water approximately 3 to 4 hours before scheduled surgery.
For postoperative use to prevent or attenuate the recurrence of signs of malignant hyperthermia when oral administration is not practical:
IV: dose must be individualized, starting with 1 mg/kg
Usual Pediatric Dose for Chronic Spasticity
For use in controlling the manifestations of clinical spasticity resulting from upper motor neuron disorders: 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.
Side effects
Insomnia , Diarrhea , Headache , nausea , dizziness , vomiting , vertigo , asthenia , sweating , difficulty urinating , tiredness , stomach painInteractions
Sodium Oxybate , Tapentadol , Nicardipine , Nisoldipine , Acetaminophen and benzhydrocodone , Oxymorphone , Ethchlorvynol , bazedoxifene/conjugated estrogens , Remdesivir , levamlodipineAlerts
Dantrolene may raise the chance of liver problems. Sometimes, liver problems have been deadly. Caution is recommended if the drug is to be used in patients with impaired pulmonary function, particularly those with obstructive pulmonary disease, and in patients with severely impaired cardiac function due to myocardial disease.
Points of recommendation
Patients should be cautioned against driving a motor vehicle or participating in hazardous occupations while taking Dantrolene sodium. Caution should be exercised in the concomitant administration of tranquilizing agents.
Dantrolene sodium might possibly evoke a photosensitivity reaction; patients should be cautioned about exposure to sunlight while taking it.
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