Do not take dantrolene if you have a liver disease such as hepatitis or cirrhosis.
Before taking this medication, tell your doctor if you
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have a breathing or lung disease,
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have heart disease, or
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have had liver disease in the past.
You may need special monitoring during your therapy with dantrolene if you have any of these conditions.
Dantrolene is in the FDA pregnancy category C. This means that it is not known whether dantrolene will harm an unborn baby. Do not take dantrolene without first talking to your doctor if you are pregnant.
It is also not known whether dantrolene passes into breast milk. Do not take dantrolene without first talking to your doctor if you are breast-feeding a baby.
Dantrolene is not approved for use by children younger than 5 years of age.
Take dantrolene exactly as directed by your doctor. If you do not understand these directions, ask your pharmacist, nurse, or doctor to explain them to you.
Take each dose with a full glass of water.
Store dantrolene at room temperature away from moisture and heat.
Take the missed dose as soon as you remember. However, if it is almost time for your next
dose, skip the missed dose and take only your next regularly scheduled dose.
If you experience any of the following serious side effects, stop taking dantrolene and seek emergency medical attention:
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an allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives);
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a rash or itching;
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black, bloody, or tarry stools or severe diarrhea;
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yellow skin or eyes; or
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seizures.
Other, less serious side effects may be more likely to occur. Continue to take dantrolene and talk to your doctor if you experience
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drowsiness, dizziness, weakness or fatigue;
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diarrhea, constipation, upset stomach, or decreased appetite;
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difficulty swallowing (use caution to prevent choking);
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headache or insomnia;
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depression or confusion;
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blurred or abnormal vision; or
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increased urination.
Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.
Use caution when driving, operating machinery, or performing other hazardous activities. Dantrolene may cause dizziness or drowsiness. If you experience dizziness or drowsiness, avoid these activities.
Use alcohol cautiously. Alcohol may increase drowsiness and dizziness while you are taking dantrolene.
Weakness in grip, leg muscles, and swallowing may occur. Use caution, especially when climbing stairs and eating meals.
Use caution when driving, operating machinery, or performing other hazardous activities. Dantrolene may cause dizziness or drowsiness. If you experience dizziness or drowsiness, avoid these activities.
Use alcohol cautiously. Alcohol may increase drowsiness and dizziness while you are taking dantrolene.
Weakness in grip, leg muscles, and swallowing may occur. Use caution, especially when climbing stairs and eating meals, to prevent falls and choking.
Avoid prolonged exposure to sunlight. Dantrolene may increase the sensitivity of your skin to sunlight. Use a sunscreen and wear protective clothing when exposure to the sun is unavoidable.
Dantrolene may increase the effects of other drugs that cause drowsiness, including antidepressants, alcohol, antihistamines, sedatives (used to treat insomnia), pain relievers, anxiety medicines, and other muscle relaxants. Tell your doctor about all medicines that you are taking, and do not take any medicine unless your doctor approves.
Drugs other than those listed here may also interact with dantrolene. Talk to your doctor and pharmacist before taking any prescription or over-the-counter medicines.
Seek emergency medical attention.
Symptoms of a dantrolene overdose include muscle weakness, drowsiness, unconsciousness, vomiting, and diarrhea.