About dantrolene

Dantrolene is used to treat chronic (long-term) muscle spasm or spasticity. Long-term muscle stiffness can occur in multiple sclerosis and other conditions where there has been damage to the nerves that supply the muscles. In these cases, muscles may contract (or shorten) tightly, and can then become stiff and harder to use. This is called spasticity.

Dantrolene works by relaxing the muscles and preventing spasms. This helps to reduce any pain and discomfort.

Before taking dantrolene

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking dantrolene it is important that your doctor or pharmacist knows:

• If you are pregnant, trying for a baby, or breast-feeding.
• If you have any problems with your liver, heart or lungs.
• If your muscles go rigid or stiff suddenly. This is because dantrolene is not suitable to use in acute muscle spasms.
• If you are taking or using any other medicines. This includes any medicines you are taking which are available to buy without a prescription, such as herbal and complementary medicines.
• If you have ever had an allergic reaction to any medicine.

How to take dantrolene

• Before you start this treatment, read the manufacturer's printed information leaflet from inside your pack. The leaflet will give you more information about the specific brand of dantrolene you have been given, and a full list of possible side-effects from taking it.
• Take dantrolene exactly as your doctor has told you. Your doctor or pharmacist will tell you how many capsules to take and when to take them. Your dose will also be on the label of the pack.
• You can take dantrolene capsules before or after your meals.
• When starting this treatment, your doctor will give you a small dose and then gradually increase it. This allows your doctor to make sure that you have the dose that helps your condition and avoids any unwanted symptoms.
• Try to take your doses of dantrolene at the same times each day. This will help you to remember to take them.
• If you do forget to take a dose, take it as soon as you remember (unless it is nearly time for your next dose, in which case leave out the missed dose). Do not take two doses together to make up for a forgotten dose.

Getting the most from your treatment

• Try to keep your regular appointments with your doctor. This is so your doctor can check on your progress, as it may take a few weeks before you begin to feel the benefit from dantrolene. If after six weeks or so you still don't feel you are improving, speak with your doctor about this.
• Dantrolene may cause drowsiness. If this happens to you, do not drive or use tools or machines, as these symptoms may put yourself and others at risk.
• It is recommended that you do not drink alcohol while you are on dantrolene. Taking dantrolene and alcohol increases the chance you may experience side-effects such as feeling sleepy or dizzy.
• Treatment with dantrolene is usually long-term unless you experience an adverse effect. Continue to take the capsules unless you are advised otherwise.

Can dantrolene cause problems?

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. These usually improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following side-effects continue or become troublesome.

Important: your doctor will have discussed with you the possibility that dantrolene can cause damage to your liver. Contact your doctor straightaway if you experience any of the following: loss of appetite, extreme tiredness, dark urine, itching, jaundice (yellowing of your skin or the whites of your eyes), feeling or being sick, or pain in your abdomen. These could be signs that your liver is being damaged and your doctor will want you to have a blood test to check for this.

If you experience any other symptoms which you think may be due to this medicine, discuss them with your doctor or pharmacist.

How to store dantrolene

• Keep all medicines out of the reach and sight of children.
• Store in a cool, dry place, away from direct heat and light.

Important information about all medicines