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Dantrium Capsules

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Generic Name: Dantrolene sodium
Product Name: Dantrium Capsules


Dantrium is the brand name for a drug known as Dantrolene. This is a muscle relaxant drug which is used to relieve chronic muscle spasms associated with disorders such as multiple sclerosis, spinal cord injury, stroke and cerebral palsy. These are all neurological problems that may be associated with excess tone or tension in the muscles. In these cases Dantrium can help relieve the muscle spasticity which in turn may reduce pain and discomfort and allow you to function better. In particular, Dantrium can help your rehabilitation process which may have been impeded by chronic spasticity.

Dantrium is NOT suitable for all conditions with muscle spasm such as rheumatic disorders. You should discuss with your doctor whether Dantrium is suited to you. There is a separate type of Dantrium called Dantrium Powder for Injection. This is given as an injection into a vein and is used to treat a separate condition called malignant hyperthermia. The drug discussed here is the capsule form of Dantrium which has different indications.


Dantrium capsules contain the active drug called Dantrolene. Following ingestion of the capsules your body slowly absorbs this drug into the bloodstream where it travels to reach its target site, the muscles. Dantrium is unlike other muscle relaxant drugs in that it acts directly on the muscle tissues to cause relaxation. It does this by inhibiting the release of calcium within muscle cells, which is a key mediator in muscle contraction. This subsequently leads to relaxation of the involved muscles. Dantrium may also have centrally mediated effects (i.e. acting on the brain) but it is not known whether this is significant in causing muscle relaxation.

Dose advice

You should not take Dantrium:

  • If you have active disease of your liver such as cirrhosis or hepatitis.
  • If you are allergic to Dantrium or any of the inactive ingredients of the capsules.
  • If muscle spasm is necessary for you to remain upright and functioning. Dantrium relieves muscle spasm but should only be used if his effect is expected to improve your function.

Before taking Dantrium you should tell your doctor:

  1. If you are pregnant or intend on becoming pregnant- There is limited experience with using Dantrium in pregnant women so one cannot be confident that this drug will not have any adverse effects on your growing fetus. You should discuss with your doctor the risks and benefits of continuing this medication during pregnancy.
  2. If you are breastfeeding or intend to breastfeed- Studies have shown that some of the medication is excreted into the breast milk. Therefore Dantrium is not recommended during lactation.
  3. If you have any other medical conditions- In particular tell your doctor if you have any liver, heart, kidney or lung problems as these can increase your risk of side effects. Liver toxicity is an important side effect of Dantrium so you will have your liver function tests (LFT) monitored carefully by your doctor during treatment.
  4. If you are allergic to any medications, foods or dyes.
  5. Any other medications you are taking (including those bought from supermarkets or the chemist)- Dantrium may interact with the oral contraceptive pill and calcium-channel blocker medications (such as verapamil). Dantrium should also be used in caution in conjunction with other CNS depressants such as alcohol.

Dantrium capsules are orange/tan in colour and come in two different doses of 25mg or 50mg. They are supplied in bottles of 100 capsules. Dantrium capsules are intended to be swallowed whole. Dantirum should always be taken as prescribed by your doctor. Doses differ between patients and your doctor will determine the best dose for you by slowly building up your dose and monitoring your response. For adults the usual starting dose is 25mg (single capsule) once daily. Your doctor may then increase this to 25mg two, three or four times daily. Your doctor will usually wait 4-7 days between each dose adjustment so they are sure of your response. If results are still not as desired doses may be further increased to 50mg two, three or four times daily. The maximum recommended daily dose is thus 200mg but doses up to 400mg are very occasionally used. High doses can damage your liver so are not recommended. Doses in children follow similar principals. The starting dose will be determined according to your child’s weight and is usually 0.5mg/kg bodyweight twice daily. This can be increased to 0.5mg/kg three or four times daily and then further up to a maximum of 2mg/kg three times daily. Doses of more than 200mg daily should not be used in children.While taking Dantrium you should be careful driving and operating machinery. Dantrium can cause drowsiness and dizziness which may impair your ability to complete these tasks. You should therefore avoid driving and operating machinery whilst using this medication and at least until you are aware of how Dantrium affects your body. Drugs such as alcohol and sleeping tablets should also be avoided as these can further exacerbate side effects of drowsiness and dizziness. In addition, whilst taking Dantrium you should avoid exposure to sunlight as Dantrium can increase your skin’s sensitivity leading to easier burning, itching and redness.


S4 (prescription required).

Common side effects

Like any other medication, Dantrium can cause side effects in some patients. The majority of these will be mild and only last for a short time following early commencement of treatment. Your doctor will also take measures such as slow dose titration and monitoring to minimise the extent of side effects. A small number of patients may experience more serious side effects that necessitate proper treatment. If you experience any of the following side-effects (or any other symptoms you think may be caused by the drug) that are worrying you, do not hesitate to discuss them with your doctor. Note that the following lists of side-effects are not necessarily exhaustive as new side effects can be discovered as more patients use the drug. The most common side effects experienced by patients treated with Dantrium are listed below. These may affect approximately 20% of patients.

  • Drowsiness.
  • Dizziness.
  • Weakness.
  • General malaise (general discomfort or feeling unwell).
  • Fatigue.
  • Diarrhoea– Diarrhoea can become quite severe in some patients. In these cases it may be necessary to cease the drug for a temporary period. If when you restart Dantrium you still experience severe diarrhoea, it may be suitable to cease the drug permanently.

Uncommon side effects

A large number of other side effects are also possible but occur infrequently (less than 1% of patients).You should tell your doctor if you experience any of the following which you believe may be attributed to the drug:

In these cases it may be necessary to lower you dose of Dantrium. You should not cease taking Dantrium suddenly unless told to by your doctor. A very small number of patients may have more serious side effects that require more urgent management. These may include:

  • Severe allergic reactions– If you notice rash, itching or hives on the skin, swelling of the face, lips, tongue or other parts of the body (angioedema) or shortness of breath or wheezing see your doctor immediately.
  • Lymphocytic lymphoma.
  • Seizures- Tell your doctor immediately if you experience any fits or convulsions.
  • Heart failure– This may present as shortness of breath or swelling of the feet or ankles. You may also notice palpitations if Dantrium affects your heart rhythm.
  • Pleural effusion.
  • Liver dysfunction- As fore mentioned, Dantrium can be toxic to your liver. If damage occurs you may have symptoms such as abdominal pain or swelling, jaundice (yellowing of the skin), pale stools, dark urine and be generally unwell.
  • Total skeletal paralysis- If you take a large dose of Dantirum (overdose) numerous muscles in the body may become paralysed. This can lead to loss of consciousness and impair breathing which can be life-threatening.

Note that the above lists of side effects are not necessarily exhausted and other side effects may occur in some patients. Therefore you should discuss any symptoms you develop with your doctor. However, do not be alarmed by these long lists of side effects as most patients will tolerate the medication well with only minor side effects. Your doctor will be able to discuss in detail further the risks and benefits of this medication for you.


  1. Australian Medicines Handbook- 16.9 Dantrolene. AMH Pty Ltd. 2006.
  2. Dantrium (R) Capsules- Consumer Medicine Information, Pfizer Australia Pty Ltd, 2005. Available [online] at: [PDF File]
  3. MIMS online- Prescribing Information. Dantrium Capsules. MIMS Australia Pty Ltd 2003.

For further information talk to your doctor.

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Posted On: 22 July, 2003
Modified On: 21 December, 2006
Reviewed On: 21 December, 2006


Created by: myVMC