Adult Medication

Brand Names: US

Dantrium; Revonto; Ryanodex

Brand Names: Canada



All products:

  • This drug may raise the chance of liver problems. Sometimes, liver problems have been deadly. This may happen at any time but most of the time has happened between the 3rd and 12th month of treatment. The chance is greatest in women, patients older than 35 years of age, and patients taking other drugs. The chance is also greater when this drug is used in high doses, even for a short time. Your doctor will be watching your liver tests. This drug must not be used for reasons other than for what it was given to you.
  • Have blood work checked as you have been told by the doctor. Talk with the doctor.


  • If your signs are not better after 45 days of use, talk with your doctor.

What is this drug used for?

  • It is used to calm muscles.
  • It is used to treat or prevent a health problem called malignant hyperthermia.

What do I need to tell my doctor BEFORE I take this drug?

All products:

  • If you have an allergy to dantrolene or any other part of this drug.
  • If you are allergic to any drugs like this one, any other drugs, foods, or other substances. Tell your doctor about the allergy and what signs you had, like rash; hives; itching; shortness of breath; wheezing; cough; swelling of face, lips, tongue, or throat; or any other signs.
  • If you are breast-feeding. Do not breast-feed while you take this drug.
  • If you are taking any of these drugs: Diltiazem or verapamil.


  • If you have liver disease.
  • If spasticity helps you keep your balance.
This is not a list of all drugs or health problems that interact with this drug.
Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take this drug with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take this drug?

All products:

  • Tell all of your health care providers that you take this drug. This includes your doctors, nurses, pharmacists, and dentists.
  • Talk with your doctor before you drink alcohol or use other drugs and natural products that slow your actions.
  • You may get sunburned more easily. Avoid sun, sunlamps, and tanning beds. Use sunscreen and wear clothing and eyewear that protects you from the sun.
  • Very bad and sometimes deadly allergic side effects have rarely happened. Talk with your doctor.
  • If you are 65 or older, use this drug with care. You could have more side effects.
  • Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using this drug while you are pregnant.


  • Avoid driving and doing other tasks or actions that call for you to be alert until you see how this drug affects you.


  • If you were given this drug before or during surgery, signs of muscle weakness may last after surgery. This includes weak grip strength or weak leg muscles. Dizziness may also happen. These effects may last for up to 48 hours. Avoid driving and doing other tasks or actions that call for you to be alert during this time and until you see how this drug affects you.
  • You may need help with standing and walking until your strength is back to normal.
  • Be careful eating meals on the day this drug was given. Trouble swallowing and choking have happened. Talk with the doctor.
  • You will be watched closely by your doctor.

What are some side effects that I need to call my doctor about right away?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

All products:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
  • Signs of liver problems like dark urine, feeling tired, not hungry, upset stomach or stomach pain, light-colored stools, throwing up, or yellow skin or eyes.
  • Choking.
  • Trouble swallowing.


  • Signs of infection like fever, chills, very bad sore throat, ear or sinus pain, cough, more sputum or change in color of sputum, pain with passing urine, mouth sores, or wound that will not heal.
  • Feeling very tired or weak.
  • Shortness of breath, a big weight gain, swelling in the arms or legs.
  • Chest pain or pressure or a fast heartbeat.
  • Blood in the urine.
  • Black, tarry, or bloody stools.
  • Throwing up blood or throw up that looks like coffee grounds.
  • Feeling confused.
  • Low mood (depression).
  • Not able to pass urine or change in how much urine is passed.
  • Very bad belly pain.
  • Seizures.
  • Very bad headache.
  • Any unexplained bruising or bleeding.
  • Change in eyesight.
  • Very bad dizziness or passing out.
  • Very hard stools (constipation).
  • Very loose stools (diarrhea).
  • Change in speech.


  • Shortness of breath.
  • This drug may cause tissue damage if the drug leaks from the vein. Tell your nurse if you have any redness, burning, pain, swelling, blisters, skin sores, or leaking of fluid where the drug is going into your body.

What are some other side effects of this drug?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

All products:

  • Feeling sleepy.
  • Dizziness.


  • Feeling tired or weak.
  • Loose stools (diarrhea).


  • Flushing.
  • Headache.
  • Upset stomach.
  • Change in voice.
These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.
You may report side effects to your national health agency.

How is this drug best taken?

Use this drug as ordered by your doctor. Read all information given to you. Follow all instructions closely.


  • Take with or without food.


  • It is given as a shot into a vein.

What do I do if I miss a dose?


  • Take a missed dose as soon as you think about it.
  • If it is close to the time for your next dose, skip the missed dose and go back to your normal time.
  • Do not take 2 doses at the same time or extra doses.


  • Call your doctor to find out what to do.

How do I store and/or throw out this drug?


  • Store at room temperature.
  • Store in a dry place. Do not store in a bathroom.


  • If you need to store this drug at home, talk with your doctor, nurse, or pharmacist about how to store it.

All products:

  • Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
  • Check with your pharmacist about how to throw out unused drugs.

General drug facts

  • If your symptoms or health problems do not get better or if they become worse, call your doctor.
  • Do not share your drugs with others and do not take anyone else’s drugs.
  • Keep a list of all your drugs (prescription, natural products, vitamins, OTC) with you. Give this list to your doctor.
  • Talk with the doctor before starting any new drug, including prescription or OTC, natural products, or vitamins.
  • Some drugs may have another patient information leaflet. If you have any questions about this drug, please talk with your doctor, nurse, pharmacist, or other health care provider.
  • If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

Consumer Information Use and Disclaimer

This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine.

Last Reviewed Date



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