Dantrolene

(dan' troe leen)

Brand Name(s): Dantrium^®; also available generically

IMPORTANT WARNING:

Dantrolene can cause severe liver damage. Do not use dantrolene for conditions other than those recommended by your doctor. Do not take more than the recommended amount prescribed by your doctor. Do not take dantrolene if you have liver disease. If you experience any of the following symptoms, call your doctor immediately: yellowing of the skin or eyes, dark urine, black tarry stools, nausea, vomiting, loss of appetite, pain in the upper right part of the stomach, or unusual bruising or bleeding.

Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests before and during your treatment to check your response to dantrolene.

WHY is this medicine prescribed?

Dantrolene is used to treat spasticity (muscle stiffness and tightness) or muscle spasms associated with spinal cord injuries, stroke, multiple sclerosis, or cerebral palsy. It is also used to prevent, treat, or reduce the risk of malignant hyperthermia (disorder that causes a fast rise in body temperature and muscle contractions), Dantrolene is in a class of medications called skeletal muscle relaxants. Dantrolene acts on the spinal cord nerves to treat spasticity and to prevent and treat malignant hyperthermia.

Are there OTHER USES for this medicine?

This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

HOW should this medicine be used?

Dantrolene comes as a capsule to take by mouth. When used to treat spasticity, it is usually taken once a day for 7 days and then increased gradually every 7 days to three to four times a day. When used to prevent malignant hyperthermia, it is usually given three to four times a day, starting 1 or 2 days before surgery. When used after a malignant hyperthermia crisis, it is usually given in 4 divided doses for 1 to 3 days . Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take dantrolene exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Your doctor will probably start you on a low dose of dantrolene for spasticity and gradually increase your dose, not more than once every 7 days. If your symptoms do not improve or get worse within 45 days of taking dantrolene, call your doctor.

What SPECIAL PRECAUTIONS should I follow?

Before taking dantrolene,

• tell your doctor and pharmacist if you are allergic to dantrolene, any other medications, or any of the ingredients in dantrolene capsules. Ask your pharmacist for a list of the ingredients.

• tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: antidepressants; medications for anxiety; calcium channel blockers such as amlodipine (Norvasc), diltiazem (Cardizem, Dilacor, Tiazac, others), felodipine (Plendil), isradipine (DynaCirc), nicardipine (Cardene), nifedipine (Adalat, Procardia), nimodipine (Nimotop), nisoldipine (Sular), and verapamil (Calan, Verelan); estrogen-containing contraceptives (birth control pills, patches, rings, and injections); or estrogen replacement therapy; medications for mental illness; medications for seizures; sedatives; sleeping pills; or tranquilizers. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.

• tell your doctor if you have or have ever had muscle spasms from a rheumatic disorder, or heart or lung disease.

• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking dantrolene, call your doctor immediately.

• you should know that dantrolene may make you drowsy. Do not drive a car or operate machinery until you know how this medication affects you.

• ask your doctor about the safe use of alcoholic beverages while you are taking dantrolene. Alcohol can make the side effects from dantrolene worse.

• you should plan to avoid unnecessary or prolonged exposure to sunlight and to wear protective clothing, sunglasses, and sunscreen. Dantrolene may make your skin sensitive to sunlight.

What should I do IF I FORGET to take a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for the missed one.

What SIDE EFFECTS can this medicine cause?

Dantrolene may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• muscle weakness
• dizziness
• diarrhea
• fatigue

In addition to the symptoms mentioned in the IMPORTANT WARNING section, if you experience and of the following symptoms, call your doctor immediately:

• seizures
• difficulty breathing or slow, shallow breathing

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

What should I know about STORAGE and DISPOSAL of this medication?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

What should I do in case of OVERDOSE?

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Symptoms of overdose may include:

• vomiting
• diarrhea
• muscle weakness
• extreme tiredness
• coma

What OTHER INFORMATION should I know?

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.

The American Society of Health-System Pharmacists, Inc. represents that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. makes no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information is not a substitute for medical care.

AHFS^® Patient Medication Information™. © Copyright, 2024. The American Society of Health-System Pharmacists^®, 4500 East-West Highway, Suite 900, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: December 15, 2019.