Dantrolene is a muscle relaxant for relief of cramping, spasms, and tightness of muscles caused by multiple sclerosis among other conditions. It acts directly on the muscles.
Dantrolene may be taken with or without food. If your physician tells you to take it in a certain way it should be taken exactly as directed.
Do not take more dantrolene or take it more often than directed. Overdosing may cause liver damage.
Dantrolene has been shown to cause cancer and noncancerous tumors in animals that were given high doses over a long period of time. You should discuss this with your physician.
Dantrolene has not been shown to cause birth defects in humans.
Dantrolene is not recommended during breast feeding.
Be sure to tell your physician if you are taking any of the following: acetaminophen; amiodarone; anabolic steroids; androgens (male hormones); antibiotics; thyroid agents; carbamazepine; carmustine; central nervous system depressants; chloroquine; daunorubicin; disulfiram; divalproex; estrogens (female hormones); etretinate; gold salts; hydroxychloroquine; mercaptopurine; methotrexate; methyldopa; naltrexone; oral contraceptives; phenothizines; phenytoin; plicamycin; tricyclic antidepressants; valproic acid.
Tell your physician if you have any of the following: emphysema; asthma; bronchitis; heart disease; liver disease.
Dantrolene will greatly add to the effects of alcohol and other central nervous system depressants. Do not drink alcohol while taking dantrolene.
Dantrolene may cause drowsiness, dizziness, vision problems or weakness in some people. Be sure you are familiar with dantrolene's effects before you drive or operate machinery.
Since dantrolene can cause liver damage it is important to have blood tests to evaluate liver function on a regular basis.
Possible Side Effects
Side effects that usually go away as your body adjusts to the medication and do not require medical attention unless they persist or are bothersome: diarrhea; dizziness; drowsiness; weakness*; nausea; unusual tiredness*; abdominal cramps; blurred or double vision; chills and fever; constipation; frequent urination; headache; loss of appetite; speech difficulties; sleep difficulties; nervousness.
Side effects that should be reported to your physician as soon as possible: seizures; pain; tenderness; changes in skin color; swelling; shortness of breath; dark urine; chest pain; confusion; severe constipation; difficult urination; skin rash; itching; yellow color in eyes or skin.
*Since it may be difficult to distinguish between certain common symptoms of MS and some side effects of dantrolene, be sure to consult your health care professional if an abrupt change of this type occurs.