How does it work?
Dixarit tablets contain the active ingredient clonidine, which is a medicine used in the prevention of migraine headaches. Clonidine is also available without a brand name, ie as the generic medicine.
Although the cause of migraine attacks is not fully understood, it is thought that the widening of blood vessels in the brain causes the pain associated with migraine attacks.
Dixarit tablets are used to prevent migraines and to treat menopausal flushing, though it is not fully understood how it works in these conditions.
Clonidine is thought to reduce the responsiveness of small blood vessels to stimuli which would normally make them contract (narrow) or dilate (widen). This prevents the changes in the blood vessels of the brain which are associated with migraine, and thus prevents attacks. It also prevents the dilatation of blood vessels and subsequent increased blood flow to the skin, which causes hot flushes in menopausal women.
Dixarit tablets need to be used for at least two to four weeks before the full effect of the treatment for migraine or hot flushes is seen.
Clonidine is used in much higher doses to treat high blood pressure (see Catapres).
What is it used for?
- Prevention of migraines and recurrent vascular headaches.
- Preventing hot flushes in women going through the menopause.
How do I take it?
- Dixarit tablets can be taken with or without food. The tablets should be swallowed with a drink of water.
- The number of tablets to be taken daily will vary depending on how well the medicine works to help relief the migraine headache or hot flushes. It is important to follow the instructions given by your doctor. These will be printed on the dispensing label your pharmacist has put on the packet of medicine.
- You should not suddenly stop taking this medicine, unless your doctor tells you otherwise, as this may cause your blood pressure to rise suddenly and symptoms such as restlessness, palpitations, nervousness, tremor, headache and abdominal symptoms. When you stop treatment with this medicine, your dose should be reduced gradually over two to four days. Follow the instructions given by your doctor.
- This medicine can cause drowsiness. If you do find this medicine makes you feel sleepy or dizzy you should not drive or operate machinery and avoid drinking alcohol.
- People who wear contact lenses should be aware that this medicine can cause dry eyes. This may mean that wearing contact lenses during treatment could irritate the surface of the eye. If you experience this, consult your doctor.
Use with caution in
- People who have problems with blood circulation in the hands, feet or lower legs due to narrowing of blood vessels (peripheral vascular disease), for example Raynaud's disease.
- People who have problems with blood circulation to the brain or heart.
- Heart failure.
- People with a slow heart rate.
- Decreased kidney function.
- People who are constipated.
- People who have problems with several nerves throughout the body, causing symptoms such as weakness, numbness, tingling or burning sensations (polyneuropathy).
- People with a history of depression.
Not to be used in
- People with a very slow heart rate, as a result of problems with the electrical signals in the heart due to sick sinus syndrome or 2nd or 3rd degree heart block.
- Rare hereditary problems of fructose intolerance, galactose intolerance, the Lapp lactase deficiency, glucose-galactose malabsorption or sucrase-isomaltase insufficiency (Dixarit tablets contain lactose and sucrose).
- This medicine is not recommended for children and adolescents under 18 years old.
This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.
If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Pregnancy and breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
- This medicine should not be used during pregnancy unless considered essential by your doctor. The expected benefit to the mother must be greater than any possible risk to the developing baby. The medicine crosses the placenta and may slow the baby's heartbeat. Ask your doctor for further information and advice.
- If you think you could be pregnant while taking this medicine you should get advice from your doctor straight away. You should not suddenly stop taking this medicine unless your doctor tells you to because this can cause your blood pressure to rise suddenly, as well as other withdrawal effects (see above).
- This medicine passes into breast milk. It is not recommended for women who are breastfeeding. Seek medical advice from your doctor.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.
Very common (affect more than 1 in 10 people)
- Drowsiness and sedation.
- Dry mouth.
- A drop in blood pressure that occurs when going from a sitting or lying position to sitting or standing, which results in dizziness and lightheadedness (postural hypotension).
Common (affect between 1 in 10 and 1 in 100 people)
- Difficulty in sleeping.
- Nausea and vomiting.
- Pain in the salivary glands.
- Erectile dysfunction (impotence).
Uncommon (affect between 1 in 100 and 1 in 1000 people)
- A general feeling of being unwell (malaise).
- Pins and needles sensations in the hands and feet.
- Narrowing of the blood vessels in the hands leading to periods of white, painful hands (Raynaud's phenomenom).
- Skin reactions such as rash or itching.
Rare (affect between 1 in 1000 and 1 in 10,000 people)
- Reduced tear flow causing dry eyes.
- Dryness of nose.
- Slowed conduction of electrical messages between the chambers of the heart (atrioventricular block).
- Pseudo-obstruction of the large bowel, which may cause abdominal pain, vomiting and constipation.
- Hair loss.
- Increased blood glucose levels.
- Enlargement of breast tissue in men.
- Slower than normal heart beat (bradycardia).
- Retention of water in the body tissues (fluid retention).
- Decreased sex drive.
- Visual disturbances.
The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.
For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
How can this medicine affect other medicines?
It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to make sure that the combination is safe.
This medicine is likely to have an additive effect with medicines that decrease blood pressure, particularly medicines that are used to treat high blood pressure (antihypertensives). This may cause dizziness, which can usually be relieved by lying down until the symptoms pass. If you feel dizzy while taking this medicine in combination with medicines that can lower blood pressure you should let your doctor know, as your doses may need adjusting. Other medicines that decrease blood pressure include the following:
- ACE inhibitors, eg enalapril
- alpha-blockers such as prazosin
- angiotensin II receptor antagonists such as losartan
- antipsychotics such as chlorpromazine
- benzodiazepines, eg temazepam, diazepam
- beta-blockers such as propranolol
- calcium-channel blockers such as verapamil, nifedipine
- diuretics, eg furosemide
- dopamine agonists, eg bromocriptine, apomorphine
- MAOI antidepressants, eg phenelzine
- nitrates, eg glyceryl trinitrate
There may be an increased risk of drowsiness and sedation if this medicine is taken with any of the following (which can also cause drowsiness):
- barbiturates, eg amobarbital, phenobarbital
- benzodiazepines, eg diazepam, temazepam
- MAOI antidepressants, eg phenelzine
- sedating antihistamines, eg chlorphenamine, hydroxyzine
- sleeping tablets, eg zopiclone
- strong opioid painkillers, eg morphine, codeine, dihydrocodeine
- tricyclic antidepressants, eg amitriptyline.
There is an increased chance of a slow heart rate if this medicine is taken in combination with digoxin or beta-blockers such as atenolol. If clonidine is taken in combination with a beta-blocker there is also an increased risk of a rebound increase in blood pressure if the clonidine is suddenly stopped. If you are taking both these medicines it is important to keep taking both of them unless otherwise directed by your doctor. When stopping treatment, the beta-blocker should be stopped several days before slowly stopping the clonidine.
Tricyclic antidepressants, eg amitriptyline, imipramine, and the related antidepressant mirtazapine, may reduce the effectiveness of clonidine. They also increase the risk of an increase in blood pressure if clonidine is stopped.
Other medicines containing the same active ingredient
Clonidine tablets are also available without a brand name, ie as the generic medicine.
Catapres contains clonidine, but is used for treating high blood pressure, not migraines.