Dantrolene (Oral)

Dantrolene helps relax certain muscles in your body. It relieves spasms, cramping, and tightness of muscles caused by medical issues like multiple sclerosis (MS), cerebral palsy, stroke, or spinal injury. Dantrolene does not cure these issues, but it may make other treatments, like physical therapy, more effective in improving your condition. Dantrolene works directly on the muscles to create its relaxant effects.

Dantrolene is also used to prevent or treat malignant hyperthermia, a medical issue that may happen in some patients during or after surgery or anesthesia. Malignant hyperthermia includes symptoms like very high fever, fast and irregular heartbeat, and breathing problems. This condition is believed to be inherited.

This medicine is available only with your doctor's prescription.

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 increase 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.

In deciding to use a medicine, you and your doctor need to consider the risks of taking the medicine against the benefits it may provide.

Allergies

Inform your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also, let your healthcare professional know about any other allergies you have, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

There have not been appropriate studies on how dantrolene affects children under 5 years of age. Its safety and effectiveness in this age group have not been established.

Geriatric

There is no information available about how dantrolene affects older patients.

Breast Feeding

There are no adequate studies in women to determine the risk to infants when using this medication during breastfeeding. Consider the potential benefits and risks before taking this medication while breastfeeding.

Interactions with Medicines

Some medicines should not be used together, while others may be used together even if an interaction might occur. In these cases, your doctor may adjust the dose, or other precautions may be necessary. It is especially important for your healthcare professional to know if you are taking any of the following medicines while using this medicine. The following interactions have been chosen based on their potential significance and may not include all possible interactions.

Using this medicine with any of the following medicines is usually not recommended, but may be necessary in some cases. If both medicines are prescribed together, your doctor may adjust the dose or how often you use one or both of the medicines.

• Alprazolam
• Amlodipine
• Amobarbital
• Aprobarbital
• Buprenorphine
• Butabarbital
• Butalbital
• Calcium Oxybate
• Carisoprodol
• Chloral Hydrate
• Chlordiazepoxide
• Chlorzoxazone
• Cinnarizine
• Clevidipine
• Clobazam
• Clonazepam
• Clorazepate
• Diazepam
• Diltiazem
• Estazolam
• Ethchlorvynol
• Felodipine
• Flunitrazepam
• Flurazepam
• Halazepam
• Isradipine
• Ketazolam
• Levoketoconazole
• Lorazepam
• Lormetazepam
• Magnesium Oxybate
• Medazepam
• Mephenesin
• Mephobarbital
• Meprobamate
• Metaxalone
• Methadone
• Methocarbamol
• Methohexital
• Methotrexate
• Midazolam
• Nicardipine
• Nifedipine
• Nimodipine
• Nisoldipine
• Nitrazepam
• Oxazepam
• Oxycodone
• Pentobarbital
• Pexidartinib
• Phenobarbital
• Potassium Oxybate
• Prazepam
• Primidone
• Quazepam
• Secobarbital
• Sodium Oxybate
• Tapentadol
• Temazepam
• Thiopental
• Triazolam
• Verapamil

Interactions with Food/Tobacco/Alcohol

Some medicines should not be taken with food or certain types of food because interactions may happen. Using alcohol or tobacco with some medicines may also cause interactions. Talk to your healthcare professional about using your medicine with food, alcohol, or tobacco.

Other Medical Problems

Having other medical problems may affect how you can use this medicine. Make sure to tell your doctor about any other medical issues you have, especially:

• Heart disease or
• Liver disease, history of or
• Lung disease (e.g., emphysema, asthma, bronchitis)—This may increase the chance of serious side effects.

• Active liver disease (e.g., hepatitis, cirrhosis) or
• Muscle spasms caused by rheumatic disorders—This medicine should not be used in patients with these conditions.

Along with its needed effects, Dantrolene (Oral) may cause some unwanted effects. Not all of these side effects may occur, but if they do, they may need medical attention. Serious side effects are very rare when dantrolene is taken for a short time, such as 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:

Less common

• Bloody or black, tarry stools
• Bloody or dark urine
• Bluish color changes in skin
• Changes in speech
• Chest pain
• Confusion
• Constipation
• Convulsions (seizures)
• Decrease in frequency of urination
• Decrease in urine volume
• Difficult urination
• Difficulty in moving
• Difficulty in passing urine (dribbling)
• Difficulty in swallowing
• Fast, pounding, or irregular heartbeat or pulse
• Increased frequency of urination
• Increased urge to urinate during the night
• Joint pain
• Light-colored stools
• Lightheadedness
• Loss of bladder control
• Mental depression
• Muscle aching or cramping
• Muscle pains or stiffness
• Muscle spasm or jerking of all extremities
• Nausea and vomiting
• Pain in lower back
• Pain or burning while urinating
• Pain, tenderness, or changes in skin color
• Painful urination
• Severe stomach pain
• Shortness of breath
• Skin rash, hives, or itching
• Slow or troubled breathing
• Sudden decrease in amount of urine
• Sudden loss of consciousness
• Swelling of foot or leg
• Swollen joints
• Unusual tiredness or weakness
• Upper right abdominal pain
• Vomiting of blood or material that looks like coffee grounds
• Waking to urinate at night
• Yellow eyes or skin

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. Your health care professional may also 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:

More common

• Diarrhea
• Dizziness
• Drowsiness
• General feeling of discomfort or illness
• Muscle weakness

Less common

• Abdominal or stomach cramps or discomfort
• Abnormal hair growth
• Acne-like rash
• Blurred or double vision or any change in vision
• Change in taste
• Chills and fever
• Disturbed color perception
• Excessive tearing
• Halos around lights
• Headache
• Itching skin
• Loss of appetite
• Night blindness
• Overbright appearance of lights
• Redness of skin
• Seeing double
• Skin rash, encrusted, scaly and oozing
• Sleeplessness
• Slurring of speech or other speech problems
• Sudden decrease in amount of urine
• Sweating
• Trouble sleeping
• Tunnel vision
• Unable to sleep
• Unusual nervousness
• Weight loss

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.

In the U.S.

• Dantrium

Available Dosage Forms:

• Capsule

Therapeutic Class: Skeletal Muscle Relaxant, Direct Acting

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.

Dosing

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.

• For oral dosage form (capsules): For prevention or treatment of malignant hyperthermia: Adults—Dose is based on body weight and must be determined by your doctor. The usual dose is 4 to 8 milligrams (mg) per kilogram (kg) of body weight each day, and is divided in 3 or 4 doses. Your doctor will tell you exactly when and how often to take your medicine. Children—Use and dose must be determined by your doctor. To relieve muscle spasms: Adults—At first, 25 milligrams (mg) once a day. Your doctor may adjust your dose as needed. However, the dose is usually not more than 100 mg four times a day. Children—Dose is based on body weight and must be determined by your doctor. At first, 0.5 milligram (mg) per kilogram (kg) of body weight twice a day. Your doctor may adjust the dose as needed. However, the dose is usually not more than 3 mg per kg four times a day or 100 mg four times a day.

Missed Dose

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.

Storage

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.