Description and Brand Names

Drug information provided by: Merative, Micromedex®

US Brand Name

  1. Dantrium

Descriptions


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.

This product is available in the following dosage forms:

  • Capsule

Before Using

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:

Allergies

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.

Pediatric

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.

Geriatric

No information is available on the relationship of age to the effects of dantrolene in geriatric patients.

Breastfeeding

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.

Drug Interactions

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.

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

Other Interactions

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:

  • Heart disease or
  • Liver disease, history of or
  • Lung disease (e.g., emphysema, asthma, bronchitis)—The chance of serious side effects may be increased.
  • Liver disease, active (e.g., hepatitis, cirrhosis) or
  • Muscle spasms caused by rheumatic disorders—Should not be used in patients with these conditions.

Proper Use

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.

Precautions

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

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:

Less common

  1. Bloody or black, tarry stools
  2. bloody or dark urine
  3. bluish color changes in skin color
  4. changes in speech
  5. chest pain
  6. confusion
  7. constipation
  8. convulsions (seizures)
  9. decrease in frequency of urination
  10. decrease in urine volume
  11. difficult urination
  12. difficulty in moving
  13. difficulty in passing urine (dribbling)
  14. difficulty in swallowing
  15. fast, pounding, or irregular heartbeat or pulse
  16. increased frequency of urination
  17. increased urge to urinate during the night
  18. joint pain
  19. light-colored stools
  20. lightheadedness
  21. loss of bladder control
  22. mental depression
  23. muscle aching or cramping
  24. muscle pains or stiffness
  25. muscle spasm or jerking of all extremities
  26. nausea and vomiting
  27. pain in lower back
  28. pain or burning while urinating
  29. pain, tenderness, or changes in skin color
  30. painful urination
  31. severe stomach pain
  32. shortness of breath
  33. skin rash, hives, or itching
  34. slow or troubled breathing
  35. sudden decrease in amount of urine
  36. sudden loss of consciousness
  37. swelling of foot or leg
  38. swollen joints
  39. unusual tiredness or weakness
  40. upper right abdominal pain
  41. vomiting of blood or material that looks like coffee grounds
  42. waking to urinate at night
  43. 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. 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:

More common

  1. Diarrhea
  2. dizziness
  3. drowsiness
  4. general feeling of discomfort or illness
  5. muscle weakness

Less common

  1. Abdominal or stomach cramps or discomfort
  2. abnormal hair growth
  3. acne-like rash
  4. blurred or double vision or any change in vision
  5. change in taste
  6. chills and fever
  7. disturbed color perception
  8. excessive tearing
  9. halos around lights
  10. headache
  11. itching skin
  12. loss of appetite
  13. night blindness
  14. overbright appearance of lights
  15. redness of skin
  16. seeing double
  17. skin rash, encrusted, scaly and oozing
  18. sleeplessness
  19. slurring of speech or other speech problems
  20. sudden decrease in amount of urine
  21. sweating
  22. trouble in sleeping
  23. tunnel vision
  24. unable to sleep
  25. unusual nervousness
  26. 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.

Portions of this document last updated: April 01, 2024

Original article: https://www.mayoclinic.org/drugs-supplements/dantrolene-oral-route/side-effects/DRG-20063299