Common questions about clonidine - Brand name: Catapres

Clonidine is a vasodilator medicine. It works by stimulating alpha receptors in the brain. This sends signals that help to relax blood vessels in the heart, which reduces your blood pressure and heart rate.

It also affects small blood vessels in other parts of the body such as the brain or skin. This helps prevent migraines and treats menopausal hot flushes or sweats.

Clonidine will start to work within 30 to 60 minutes of you taking a dose. However, it may take 2 to 4 weeks until the medicine is fully effective and you start to feel better.

If you're taking clonidine for high blood pressure, you may not have any symptoms. In these cases, you may not feel any different when you take clonidine. This does not mean that the medicine is not working. It's important to keep taking it.

You'll need to keep taking clonidine regularly for it to keep working, even if you feel well. Your doctor will probably ask you to have regular check-ups to make sure clonidine is working.

If you do not feel that clonidine is working after a few weeks, speak to your doctor. Do not stop taking it without talking to a doctor. Stopping it suddenly can cause dangerously high blood pressure and withdrawal side effects.

Whatever you're taking clonidine for, stopping it suddenly can cause a dangerous increase in your blood pressure. It can also cause withdrawal side effects such as restlessness, heart palpitations, agitation, nervousness, tremor or shaking hands, headaches or feeling sick (nausea).

Do not stop taking clonidine without talking to a doctor. If you need to stop taking it, the dose should be reduced gradually. Your doctor can advise you how to do this safely.

There are several types of medicine that may be used to treat high blood pressure. They work in different ways, and certain medicines may work better for different people. You'll often need to take more than one medicine to keep your blood pressure under control.

Your doctor will advise which medicines are best for you depending on your age, ethnicity and any other medical conditions you have.

Clonidine is not used very often for high blood pressure. Other medicines are usually preferred. Because of its side effects, doctors usually only suggest trying clonidine if other blood pressure-lowering medicines have not worked or are not suitable for you.

Hormone replacement therapy (HRT) is the most effective and widely used treatment for menopausal hot flushes or sweats.

Non-hormonal treatments such as clonidine are only recommended if you do not want to take HRT, or if HRT is not suitable or causes side effects.

Other non-hormonal alternatives are SSRI antidepressants (fluoxetine, citalopram, escitalopram, sertraline or paroxetine), venlafaxine, gabapentin or pregabalin. Some research suggest these medicines are probably more effective than clonidine. However you may find clonidine works for you.

There are other treatments including things you can do that may help to control your menopausal symptoms. Talk to your doctor or pharmacist about finding the right treatment for you.

There are a few different medicines that may help to prevent migraines or similar types of headaches (sometimes known as vascular headaches). Your doctor will advise which might be best for you depending on your age, sex, other health conditions and other medicines you're taking.

The most effective treatments seem to be topiramate or propranolol. Other alternatives are amitriptyline (or other tricyclic antidepressants), sodium valproate or pizotifen.

Although clonidine has been used for many years, it does not seem to be as effective as other medicines for preventing migraines. For that reason it's usually only used if other medicines have not worked or are not suitable.

Clonidine has a number of other possible uses. Specialist doctors may sometimes suggest trying clonidine as a treatment for:

• Tourette's syndrome or tics
• attention deficit hyperactivity disorder (ADHD) or other behavioural problems in children
• sleep problems in young children
• muscle problems such as weakness and stiffness (spasticity) or unusual muscle contractions, spasms or movements (dystonia)

For more information about how to give clonidine to children, see Medicines for Children: Clonidine for Tourette's syndrome, ADHD and sleep-onset disorder.

In hospital may occasionally be used:

• to treat withdrawal symptoms in newborn babies whose mothers were taking opioid replacement medicines such as methadone during pregnancy
• as a sedative (a medicine to help you stay calm and a bit sleepy) before or during procedures
• to help diagnose growth hormone deficiency in children
• by injection, possibly into the spine, to treat various types of pain

There is not much information, but there are studies that suggest clonidine may help with hot flushes caused by certain breast cancer treatments such as tamoxifen.

However, there are other medicines that may work better or have fewer side effects than clonidine.

Talk to your specialist cancer doctor or nurse about possible treatments if you're having hot flushes due to your breast cancer treatment.

No, it's important to keep taking clonidine before surgery.

Make sure you tell the doctors and nurses treating you that you're taking clonidine.

Take your clonidine tablets or liquid into hospital with you. You'll need to start taking clonidine again as soon as possible after the surgery.

It's not a common side effect, but clonidine may occasionally cause weight gain.

Eating a healthy balanced diet and regular exercise can help you manage your weight.

Clonidine does not affect any type of contraception, including the combined pill and emergency contraception.

But some types of hormonal methods of contraception, such as the combined pill, the contraceptive patch and the contraceptive vaginal ring, are not usually recommended if you have high blood pressure or migraines.

Talk to your doctor if you're taking or using a combined hormonal contraceptive.

Clonidine can make you feel sleepy and dizzy. If this happens to you, do not drive, cycle or use machinery or tools until you feel better.

It's an offence to drive a car if your ability to drive safely is affected. It's your responsibility to decide if it's safe to drive. If you're in any doubt, do not drive.

Talk to your doctor or pharmacist if you're unsure whether it's safe for you to drive while taking clonidine. GOV.UK has more information on the law on drugs and driving.

You can drink alcohol while taking clonidine, but it's likely to make you feel sleepy and may make some of the side effects of clonidine worse. It's usually best not to drink any alcohol until you see how the medicine makes you feel.

If you do drink alcohol, make sure it's only in small amounts and stick to the national guidelines of no more than 14 units a week for men and women.

If you're taking clonidine to treat high blood pressure, remember that drinking over the recommended limit regularly can increase your risk of high blood pressure and heart disease. This can increase your risk of having a heart attack or stroke.

There are not any foods you need to avoid while taking clonidine, but eating a healthy balanced diet can help if you have high blood pressure.

It’s best to avoid any foods that seem to be triggers that can cause migraines or menopausal hot flushes or sweats.

If you're taking clonidine to treat high blood pressure the following lifestyle changes can help:

• Quit smoking – smoking increases your heart rate and blood pressure. Quitting smoking will cut your risk of heart attack and stroke. Try to avoid secondhand smoke, too.
• Cut down on alcohol – try to keep to the recommended guidelines of no more than 14 units of alcohol a week. A standard glass of wine (175ml) is 2 units. A pint of lager or beer is usually 2 to 3 units of alcohol.
• Drink less caffeine, such as tea, coffee, cola and energy drinks.
• Exercise – regular exercise keeps your heart and blood vessels in good condition. It does not need to be too energetic, walking every day is enough.
• Eat well – aim to eat a diet that includes plenty of fruit and vegetables, wholegrains, fat-free or low-fat dairy products and lean proteins. It's a good idea to follow these tips for a lower salt diet. Aim for no more than 6g of salt a day.
• Deal with stress – when you're anxious or upset, your heart beats faster, you breathe more heavily and your blood pressure often goes up. This raises your risk of heart attack and stroke. Find ways to reduce stress in your life. To give your heart a rest, try napping or putting your feet up when possible. Spend time with friends and family to be social and help keep stress at bay.

One of the best ways of preventing migraines is recognising the things that trigger an attack and trying to avoid them.

You may find you tend to have a migraine after eating certain foods or when you're stressed, and by avoiding this trigger you can prevent a migraine.

Find out more about the causes of migraines

If you have hot flushes and night sweats as a result of the menopause, simple changes may sometimes help, such as:

• wearing light clothing
• keeping your bedroom cool at night
• taking a cool shower, using a fan or having a cold drink
• trying to reduce your stress levels
• avoiding potential triggers, such as spicy food, caffeine, smoking and alcohol
• taking regular exercise and losing weight if you're overweight