Dantrolene (Oral route)
Dantrolene has a potential for hepatotoxicity and symptomatic hepatitis (fatal and non-fatal) has been reported at various dose levels of the drug. Risk of hepatic injury appears to be greater in patients taking a higher dosage (800 mg or more per day), in females, in patients over 35 years of age, and in patients taking other medication(s) in addition to dantrolene. Monitor hepatic function including frequent determination of SGOT or SGPT during therapy. Discontinue therapy after 45 days if no observable benefit is derived from therapy .
Skeletal Muscle Relaxant, Direct Acting
Uses of This Medicine:
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. Malignant hyperthermia consists of a group of symptoms including very high fever, fast and irregular heartbeat, and breathing problems. It is believed that the tendency to develop malignant hyperthermia is inherited.
This medicine is available only with your doctor's prescription.
Before Using This Medicine:
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Appropriate studies have not been performed on the relationship of age to the effects of dantrolene in children below 5 years of age. Safety and efficacy have not been established.
No information is available on the relationship of age to the effects of dantrolene in geriatric patients.
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Other medical problems—
The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:
Proper Use of This Medicine:
Dantrolene may be taken with or without food or on a full or empty stomach. However, if your doctor tells you to take the medicine a certain way, take it exactly as directed.
Take this medicine only as directed by your doctor. Do not take more of it and do not take it more often than your doctor ordered.
The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Ask your healthcare professional how you should dispose of any medicine you do not use.
Precautions While Using This Medicine:
If you will be taking dantrolene for a long time (e.g., several months at a time), your doctor should check your progress at regular visits. Blood tests will be needed to check for unwanted effects.
This medicine will add to the effects of alcohol and other CNS depressants (medicines that slow down the nervous system, possibly causing drowsiness). Some examples of CNS depressants are antihistamines or medicine for hay fever, other allergies, or colds; sedatives, tranquilizers, or sleeping medicine; prescription pain medicine or narcotics; barbiturates; medicine for seizures; other muscle relaxants; or anesthetics, including some dental anesthetics. Therefore, do not drink alcoholic beverages, and check with your doctor before taking any of the medicines listed above, while you are using this medicine.
This medicine may cause drowsiness, dizziness or lightheadedness, vision problems, or muscle weakness in some people. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or are not alert, well-coordinated, and able to see well.
This medicine may make your skin more sensitive to sunlight. Use a sunscreen when you are outdoors. Avoid sunlamps and tanning beds.
Side Effects of This Medicine:
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention. Serious side effects are very rare when dantrolene is taken for a short time, for example, when it is used for a few days before, during, or after surgery or anesthesia to prevent or treat malignant hyperthermia. However, serious side effects may occur, especially when the medicine is taken for a long time.
Check with your doctor immediately if any of the following side effects occur:
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Last Updated: 6/13/2013
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