Medically reviewed on Jan 30, 2017
What is dantrolene?
Dantrolene is a muscle relaxer.
Dantrolene is also used to prevent muscle stiffness and spasms caused by malignant hyperthermia (a rapid rise in body temperature and severe muscle contractions) that can occur during surgery with certain types of anesthesia.
Dantrolene may also be used for purposes not listed in this medication guide.
You should not use dantrolene if you have active liver disease. Do not use dantrolene at a time when you need muscle tone for safe balance and movement during certain activities.
Dantrolene can cause life-threatening liver damage, especially if you take high doses. Do not take dantrolene in larger amounts or for longer than recommended.
Before taking this medicine
You should not use dantrolene if you are allergic to it, or if you have:
active liver disease such as hepatitis or cirrhosis.
You may be more likely to develop liver problems while taking dantrolene if you are a woman, if you are older than 35, or if you also take other medications. Ask your doctor about your individual risk.
To make sure dantrolene is safe for you, tell your doctor if you have:
a history of liver disease;
heart disease or prior heart attack; or
if you also use a narcotic (opioid) medication.
It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using dantrolene.
Dantrolene can pass into breast milk and may harm a nursing baby. You should not breast-feed while using this medicine.
Dantrolene should not be given to a child younger than 5 years old.
How should I take dantrolene?
Your doctor will perform blood tests to make sure you do not have conditions that would prevent you from safely using dantrolene.
Follow all directions on your prescription label. Your doctor may occasionally change your dose. Dantrolene can cause life-threatening liver damage, especially if you take high doses or take the medicine long-term. Use only your prescribed dose of dantrolene. Do not take this medicine in larger amounts or for longer than recommended.
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.
Call your doctor if your muscle symptoms do not improve, or if they get worse.
If you need surgery, tell the surgeon ahead of time that you are using dantrolene.
Store at room temperature away from moisture, heat, and light. Keep the bottle tightly closed when not in use.
What happens if I miss a dose?
Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
What should I avoid while taking dantrolene?
Do not use dantrolene at a time when you need muscle tone for safe balance and movement during certain activities. In some situations, it may be dangerous for you to have reduced muscle tone.
This medication may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.
Drinking alcohol with dantrolene can cause side effects.
Avoid exposure to sunlight or tanning beds. Dantrolene can make you sunburn more easily. Wear protective clothing and use sunscreen (SPF 30 or higher) when you are outdoors.
Dantrolene side effects
Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Call your doctor right away if you have signs of liver problems--nausea, upper stomach pain, itching, tired feeling, loss of appetite, dark urine, clay-colored stools, or jaundice (yellowing of the skin or eyes). These side effects may be most likely to occur between 3 and 12 months of your treatment with dantrolene.
Also call your doctor right away if you have:
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.
Common side effects may include:
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.
See also: Side effects (in more detail)
What other drugs will affect dantrolene?
Taking dantrolene with other drugs that make you sleepy or slow your breathing can cause dangerous side effects or death. Ask your doctor before taking a sleeping pill, narcotic pain medicine, prescription cough medicine, a muscle relaxer, or medicine for anxiety, depression, or seizures.
Liver problems may be more likely in women over 35 who use estrogen. Tell your doctor if you use hormone replacement medicine, or hormonal birth control (pills, injections, implants, skin patches, or vaginal rings).
Other drugs may interact with dantrolene, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
Copyright 1996-2018 Cerner Multum, Inc. Version: 6.01.
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- En Español
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