dantrolene

Generic Name: dantrolene (oral) (DAN troe leen)

Brand names: Dantrium, Dantrium Intravenous, Revonto

What is dantrolene?

Dantrolene is a muscle relaxant.

Dantrolene is used to treat muscle spasticity (stiffness and spasms) caused by conditions such as a spinal cord injury, stroke, cerebral palsy, or multiple sclerosis.

Dantrolene is also used to prevent muscle stiffness and spasms caused by malignant hyperthermia (a rapid rise in body temperature) that can occur during surgery with certain types of anesthesia.

Dantrolene may also be used for other purposes not listed in this medication guide.

What is the most important information I should know about dantrolene?

You should not take this medication if you are allergic to dantrolene, or if you have liver disease such as hepatitis or cirrhosis. You may be more likely to develop liver problems while taking dantrolene if you are a woman, or if you are older than 35. Talk with your doctor about your individual risk. Do not use dantrolene at a time when muscle tone is needed to assure safe balance and movement for certain activities. In some situations, it may endanger your physical safety to be in a state of reduced muscle tone.

Before taking dantrolene, tell your doctor if you have a history of liver disease, a breathing disorder such as COPD, heart disease, or a history of heart attack.

Dantrolene can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be awake and alert. Dantrolene can cause muscle weakness, which can affect your ability to swallow. Use caution to prevent choking while you are eating meals. Talk with your doctor if you are unable to eat because of this side effect. Avoid drinking alcohol. It can increase some of the side effects of dantrolene.

Your doctor may occasionally change your dose to make sure you get the best results from this medication.

What should I discuss with my healthcare provider before taking dantrolene?

You should not take this medication if you are allergic to dantrolene, or if you have liver disease such as hepatitis or cirrhosis. You may be more likely to develop liver problems while taking dantrolene if you are a woman, or if you are older than 35. Talk with your doctor about your individual risk.

If you have any of these other conditions, you may need a dose adjustment or special tests to safely use this medication:

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  a history of liver disease;

  
  


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  a breathing disorder such as COPD (chronic obstructive pulmonary disease); or

  
  


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  heart disease, or a history of heart attack.

  
  

FDA pregnancy category C. It is not known whether dantrolene is harmful to an unborn baby. Before taking this medication, tell your doctor if you are pregnant or plan to become pregnant during treatment. Dantrolene can pass into breast milk and may harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby. Dantrolene should not be given to a child younger than 5 years old.

How should I take dantrolene?

Take this medication exactly as prescribed by your doctor. Do not take it in larger amounts or for longer than recommended. Follow the directions on your prescription label.

Your doctor may occasionally change your dose to make sure you get the best results from this medication.

Take this medicine with a full glass of water. If you take dantrolene within 4 hours before surgery, use only enough water needed to swallow the pill. Dantrolene can cause muscle weakness, which can affect your ability to swallow. Use caution to prevent choking while you are eating meals. Talk with your doctor if you are unable to eat because of this side effect. Store dantrolene at room temperature away from moisture and heat.

See also: Dantrolene dosage (in more detail)

What happens if I miss a dose?

Take the missed dose as soon as you remember. If it is almost time for your next dose, wait until then to take the medicine and skip the missed dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention if you think you have used too much of this medicine.

Overdose symptoms may include vomiting, diarrhea, and extreme drowsiness or muscle weakness.

What should I avoid while taking dantrolene?

Do not use dantrolene at a time when muscle tone is needed to assure safe balance and movement for certain activities. In some situations, it may endanger your physical safety to be in a state of reduced muscle tone. Dantrolene can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be awake and alert. Avoid drinking alcohol. It can increase some of the side effects of dantrolene. Avoid exposure to sunlight, sunlamps, or tanning beds. Dantrolene can make your skin more sensitive to sunlight, and a sunburn may result. Wear protective clothing and use sunscreen (SPF 15 or higher) when you are outdoors.

Dantrolene side effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat. Call your doctor at once if you have a serious side effect such as:

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  severe diarrhea or constipation;

  
  


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  weak or shallow breathing;

  
  


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  pale skin, easy bruising or bleeding;

  
  


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  trouble swallowing, especially if it causes choking;

  
  


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  nausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);

  
  


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  black, bloody, or tarry stools;

  
  


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  coughing up blood or vomit that looks like coffee grounds;

  
  


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  seizure (black-out or convulsions); or

  
  


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  urinating less than usual or not at all.

  
  

Less serious side effects may include:

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  drowsiness, dizziness, weakness, tired feeling;

  
  


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  mild diarrhea or constipation;

  
  


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  mild nausea, vomiting, stomach pain;

  
  


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  problems with speech, balance, or walking;

  
  


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  headache, confusion, vision problems;

  
  


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  sleep problems (insomnia);

  
  


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  sweating, drooling; or

  
  


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  urinating more than usual.

  
  

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Dantrolene Dosing Information

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. This dose should be effective provided that the usual precautions, such as avoidance of established malignant hyperthermia triggering agents, are followed. Additional IV dantrolene may be indicated during anesthesia and surgery because of the appearance of early clinical and/or blood gas signs of malignant hyperthermia or because of prolonged surgery. Additional doses must be individualized.

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. Adjustment can usually be made within the recommended dosage range to avoid incapacitation (weakness, drowsiness, etc.) or excessive gastrointestinal irritation (nausea and/or vomiting).

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.

For use in the management of fulminant hypermetabolism of skeletal muscle characteristic of malignant hyperthermia crisis:

IV: (Starting dose = Minimum Dose) 1 mg/kg administered by continuous rapid intravenous push and continued until symptoms subside or the maximum cumulative dose of 10 mg/kg has been reached.

As soon as the malignant hyperthermia reaction is recognized, all anesthetic agents should be discontinued. The administration of 100% oxygen is also recommended.

If the physiologic and metabolic abnormalities reappear, the regimen may be repeated. It is important to emphasize that administration of dantrolene intravenous should be continuous until symptoms subside. The effective dose to reverse the crisis is directly dependent upon the individual's degree of susceptibility to malignant hyperthermia, the amount and time of exposure to the triggering agent, and the time elapsed between onset of the crisis and initiation of treatment.

Oral: 4 to 8 mg/kg/day orally in four divided doses administered for 1 to 3 days following a malignant hyperthermia crisis to prevent recurrence of the manifestations of malignant hyperthermia.

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.

Prior to administration, consideration should be given to the potential response to treatment. A decrease in spasticity sufficient to allow a daily function not otherwise attainable should be the therapeutic goal of treatment with dantrolene.

It is important to establish a therapeutic goal (regain and maintain a specific function such as therapeutic exercise program, utilization of braces, transfer maneuvers, etc.) before beginning dantrolene therapy.

Dosage should be titrated and individualized for maximum effect. The lowest dose compatible with optimal response is recommended.

Some patients will not respond until higher daily dosage is achieved. Each dosage level should be maintained for seven days to determine the patient's response. If no further benefit is observed at the next higher dose, dosage should be decreased to the previous lower dose.

Therapy with a dose four times daily may be necessary for some individuals. Doses higher than 100 mg four times daily should not be used.

In view of the potential for liver damage in long-term dantrolene use, therapy should be stopped if benefits are not evident within 45 days.

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. This dose should be effective provided that the usual precautions, such as avoidance of established malignant hyperthermia triggering agents, are followed. Additional IV dantrolene may be indicated during anesthesia and surgery because of the appearance of early clinical and/or blood gas signs of malignant hyperthermia or because of prolonged surgery. Additional doses must be individualized.

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. Adjustment can usually be made within the recommended dosage range to avoid incapacitation (weakness, drowsiness, etc.) or excessive gastrointestinal irritation (nausea and/or vomiting).

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.

For use in the management of fulminant hypermetabolism of skeletal muscle characteristic of malignant hyperthermia crisis:

IV: (Starting dose = Minimum Dose) 1 mg/kg administered by continuous rapid intravenous push and continued until symptoms subside or the maximum cumulative dose of 10 mg/kg has been reached.

As soon as the malignant hyperthermia reaction is recognized, all anesthetic agents should be discontinued. The administration of 100% oxygen is also recommended.

If the physiologic and metabolic abnormalities reappear, the regimen may be repeated. It is important to emphasize that administration of dantrolene intravenous should be continuous until symptoms subside. The effective dose to reverse the crisis is directly dependent upon the individual's degree of susceptibility to malignant hyperthermia, the amount and time of exposure to the triggering agent, and the time elapsed between onset of the crisis and initiation of treatment.

Oral: 4 to 8 mg/kg/day orally in four divided doses administered for 1 to 3 days following a malignant hyperthermia crisis to prevent recurrence of the manifestations of malignant hyperthermia.

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.

Dosage should be titrated and individualized for maximum effect. The lowest dose compatible with optimal response is recommended.

Some patients will not respond until higher daily dosage is achieved. Each dosage level should be maintained for seven days to determine the patient's response. If no further benefit is observed at the next higher dose, dosage should be decreased to the previous lower dose.

Therapy with a dose four times daily may be necessary for some individuals. Doses higher than 100 mg four times daily should not be used.

In view of the potential for liver damage in long-term dantrolene use, therapy should be stopped if benefits are not evident within 45 days.

What other drugs will affect dantrolene?

Cold or allergy medicine, sedatives, narcotic pain medicine, sleeping pills, and medicine for seizures, depression or anxiety can add to sleepiness caused by dantrolene. Tell your doctor if you regularly use any of these medicines, or any other muscle relaxers.

Tell your doctor about all other medications you use, especially:

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  birth control pills and other hormones; or

  
  


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  a heart or blood pressure medication such as amlodipine (Norvasc), diltiazem (Tiazac, Cartia, Cardizem), felodipine (Plendil), nicardipine (Cardene), nifedipine (Procardia, Adalat), nimodipine (Nimotop), nisoldipine (Sular), or verapamil (Calan, Covera, Isoptin, Verelan).

  
  

This list is not complete and there may be other drugs that can interact with dantrolene. Tell your doctor about all your prescription and over-the-counter medications, vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start a new medication without telling your doctor.

More dantrolene resources

• Dantrolene Side Effects (in more detail)
• Dantrolene Dosage
• Dantrolene Use in Pregnancy & Breastfeeding
• Drug Images
• Dantrolene Drug Interactions
• Dantrolene Support Group
• 3 Reviews for Dantrolene - Add your own review/rating

• dantrolene Advanced Consumer (Micromedex) - Includes Dosage Information


• Dantrolene MedFacts Consumer Leaflet (Wolters Kluwer)


• Dantrolene Prescribing Information (FDA)


• Dantrium Prescribing Information (FDA)


• Dantrium Monograph (AHFS DI)


• Dantrium Intravenous Advanced Consumer (Micromedex) - Includes Dosage Information


• Dantrium Intravenous Prescribing Information (FDA)

Compare dantrolene with other medications

• Malignant Hyperthermia
• Spasticity

Where can I get more information?

• Your pharmacist can provide more information about dantrolene.

See also: dantrolene side effects (in more detail)