1. About clopidogrel
Clopidogrel is an antiplatelet medicine, or blood thinner. It makes your blood flow through your veins more easily.
This means that your blood will be less likely to make a dangerous blood clot.
Taking clopidogrel helps prevent blood clots if you have an increased risk of having them.
Your risk is higher if you have or have had:
- a heart attack
- unstable angina
- a stroke or "mini-stroke" (transient ischaemic attack or TIA)
- peripheral arterial disease
- an operation on your heart or blood vessels, such as a coronary stent insertion
Clopidogrel comes as tablets and is only available on prescription.
2. Key facts
- The usual dose for clopidogrel is 75mg once a day.
- Your doctor may prescribe clopidogrel with or instead of low dose aspirin.
- The main side effect of clopidogrel is bleeding more easily than normal. You may have nosebleeds, heavier periods, bleeding gums or bruising.
- You can drink alcohol with clopidogrel. But do not drink too much while taking this medicine. It can irritate your stomach.
- Clopidogrel is also called by the brand names Grepid and Plavix.
3. Who can and can't take clopidogrel
Clopidogrel can be taken by adults aged 18 and over.
Clopidogrel isn't suitable for some people. To make sure this medicine is safe for you, tell your doctor if you:
- have had an allergic reaction to clopidogrel or any other medicines in the past
- have a stomach ulcer or have had stomach ulcers in the past
- have had bleeding in your brain (a brain haemorrhage)
- have a bleeding disorder, such as haemophilia
- have liver or kidney problems
- are trying to get pregnant, already pregnant or breastfeeding
4. How and when to take it
Clopidogrel can be taken once a day, at the same time each day.
You can take clopidogrel with or without food.
How much will I take?
The usual dose is 75mg a day. Occasionally a one-off higher dose, such as 300mg or 600mg, may be prescribed.
What if I forget to take it?
If you forget to take clopidogrel, take it as soon as you remember.
If you don't remember until the following day, skip the missed dose.
Do not take a double dose to make up for a forgotten dose.
If you often forget doses, it may help to set an alarm to remind you.
You could also ask your pharmacist for advice on other ways to help you remember to take your medicine.
What if I take too much?
Accidentally taking 1 or 2 extra tablets is unlikely to harm you.
But the amount of clopidogrel that can lead to overdose is different from person to person.
Contact your doctor straight away if you have taken some extra tablets and notice any signs of bleeding.
5. Side effects
Like all medicines, clopidogrel can cause side effects, although not everyone gets them.
Common side effects
These common side effects happen in more than 1 in 100 people.
Talk to your doctor or pharmacist if these side effects bother you or don't go away:
- bleeding more easily than normal - nosebleeds, bruising more easily or bleeding that takes longer to stop
- stomach pain
- indigestion or heartburn
Serious side effects
Serious side effects are rare and happen in less than 1 in 1,000 people.
Call a doctor straight away if:
- you're coughing up blood, or there's blood in your pee, poo or vomit
- your skin or the whites of your eyes turn yellow - these can be signs of liver problems
- you feel very tired or have signs of infections, such as a fever (38C or above) or sore throat - these can be signs of a blood or bone marrow disorder
Serious allergic reaction
In rare cases, clopidogrel can cause a serious allergic reaction (anaphylaxis).
Urgent advice: Contact a doctor straight away if:
- you get a skin rash that may include itchy, red, swollen, blistered or peeling skin
- you're wheezing
- you get tightness in the chest or throat
- you have trouble breathing or talking
- your mouth, face, lips, tongue or throat start swelling
These are warning signs of a serious allergic reaction. A serious allergic reaction is an emergency.
These are not all the side effects of clopidogrel. For a full list, see the leaflet inside your medicines packet.
You can report any suspected side effect to the UK safety scheme.
6. How to cope with side effects
What to do about:
- bleeding more easily than normal - be careful when doing activities that might cause an injury or a cut. Always wear a helmet when cycling. Wear gloves when you use sharp objects like scissors, knives, and gardening tools. Use an electric razor instead of wet shaving, and use a soft toothbrush and waxed dental floss to clean your teeth. See a doctor if you're worried about any bleeding.
- diarrhoea - drink plenty of water or other fluids if you have diarrhoea. Speak to a pharmacist if you have signs of dehydration, such as peeing less than usual or having dark, strong-smelling pee. Do not take any other medicines to treat diarrhoea without speaking to a pharmacist or doctor.
- stomach pain - try to rest and relax. It can help to eat and drink slowly and have smaller and more frequent meals. Putting a heat pad or covered hot water bottle on your stomach may also help. If you're in a lot of pain, speak to your pharmacist or doctor.
- indigestion or heartburn - take your clopidogrel a few minutes before or after a meal. If the indigestion doesn't go away, it could be a sign that you have a stomach ulcer. Talk to your doctor - they may prescribe something to protect your stomach or switch you to a different medicine.
7. Pregnancy and breastfeeding
Clopidogrel isn't normally recommended in pregnancy or when breastfeeding.
If you're trying to get pregnant or are already pregnant, talk to your doctor about the possible benefits or harms of taking clopidogrel.
These will depend on how many weeks pregnant you are and the reason you need to take it. There may be other treatments that are safer for you.
Clopidogrel and breastfeeding
If you're breastfeeding, your doctor will be able to explain the benefits and risks of taking clopidogrel while breastfeeding, and will recommend the best treatment for you and your baby.
Non-urgent advice: Tell your doctor if you're:
- trying to get pregnant
8. Cautions with other medicines
Some medicines interfere with the way clopidogrel works.
Tell your doctor if you're taking these medicines before you start taking clopidogrel:
- medicines to thin blood or prevent blood clots, such as aspirin, warfarin, rivaroxaban or apixaban
- non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen
- antidepressants called selective serotonin reuptake inhibitors (SSRIs), such as citalopram
- indigestion medicines called proton pump inhibitors (PPIs), such as omeprazole
Taking clopidogrel with everyday painkillers
Your doctor may prescribe daily low dose aspirin (75mg tablets) to take together with clopidogrel. Or they may prescribe clopidogrel instead of daily low dose aspirin if you have problems with aspirin.
You can take paracetamol together with clopidogrel.
Taking clopidogrel with indigestion medicines
If you have indigestion and need a medicine to protect your stomach, your doctor can prescribe you a different PPI, such as lansoprazole.
You can take other indigestion remedies such as antacids at the same time as clopidogrel. Your pharmacist will be able to recommend a suitable indigestion remedy for you.
Mixing clopidogrel with herbal remedies and supplements
There might be a problem with taking some herbal remedies and supplements with clopidogrel, especially ones that can affect your blood (for example, ginkgo).
St John's wort (used for depression) can increase the levels of clopidogrel in your blood. This can increase your risk of bleeding.
Tell your doctor or pharmacist if you're taking any other medicines, including herbal remedies, vitamins or supplements.
9. Common questions
How does clopidogrel work?
Clopidogrel slows the blood's clotting action by making platelets less sticky.
Platelets are blood cells that stick together to block cuts and breaks in blood vessels.
But in people at risk of heart attack or stroke, platelets can stick together inside already narrowed blood vessels to form a clot. The clot can stop blood flowing to the heart or brain and cause a heart attack or stroke.
If you take it every day, clopidogrel stops platelets clumping together to form unwanted blood clots. This prevents heart attacks and strokes.
How long does it take to work?
Clopidogrel works within 2 hours of taking it.
When will I feel better?
You may not notice any difference in how you feel after you start taking clopidogrel. This doesn't mean that the medicine isn't working.
Carry on taking clopidogrel even if you feel well, as you'll still be getting the benefits.
How long will I take it for?
You may need to take clopidogrel for a few weeks or months, or you may have to take it for the rest of your life.
Is it safe to take it for a long time?
Clopidogrel is generally safe to take for a long time. In fact, it works best if you take it for many months or even years.
If you're at risk of getting a stomach ulcer, your doctor may prescribe a medicine to help protect your stomach while you're taking clopidogrel.
What will happen if I stop taking it?
Do not stop taking clopidogrel without talking to your doctor.
If you stop taking clopidogrel, the rate at which your blood clots will return to what it was before you started taking it - usually within 5 days of stopping. This means you may be at increased risk of serious problems like heart attacks or strokes.
Are there any other similar medicines?
Not all medicines that prevent blood clots are suitable for everyone.
Talk to your doctor or pharmacist to find out why you have been recommended a particular medicine.
How does clopidogrel compare with other antiplatelet medicines like ticagrelor?
Both clopidogrel and ticagrelor work to:
- prevent blood clots
- prevent future heart attacks - if you have already had a heart attack
But ticagrelor is not approved for preventing further strokes if you have already had a stroke. In this case, your doctor may prescribe clopidogrel instead.
You'll usually take clopidogrel once a day, while ticagrelor is taken twice a day.
Clopidogrel may be less likely to cause bleeding than ticagrelor.
Can I drink alcohol with it?
Yes, you can drink alcohol while taking clopidogrel, as long as you stick to the national guidelines of no more than 14 units a week for men and women.
A standard glass of wine (175ml) is 2 units. A pint of lager or beer is usually 2 to 3 units of alcohol.
Drinking too much alcohol while you're taking clopidogrel can irritate your stomach. There's a risk that you could get a stomach ulcer.
Is there any food or drink I need to avoid?
Do not drink grapefruit juice while taking clopidogrel. Grapefruit juice may increase the blood-thinning effect of your medicine.
Will I need to stop clopidogrel before surgery or dental treatment?
Because of the risk of bleeding, you may need to stop taking clopidogrel for a short time before having surgery or dental work.
Do not stop taking clopidogrel without first talking to your doctor or dentist. They'll tell you if you need to stop taking clopidgrel before a procedure.
Can I have vaccinations?
Yes, you can have vaccinations while taking clopidogrel.
It's a good idea to mention to the doctor or nurse that you're taking a blood thinner.
Will it affect my fertility?
There's no firm evidence to suggest that taking clopidogrel will reduce fertility in either men or women.
But speak to a pharmacist or your doctor before taking it if you're trying to get pregnant.
Will it affect my sex life?
Clopidogrel won't affect your sex life.
Can I drive or ride a bike?
Clopidogrel doesn't affect your concentration, so you can drive or ride a bike while you're taking it.
Can lifestyle changes help?
If you have been prescribed clopidogrel, you can also boost your health by making some key lifestyle changes.
- 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.
- Exercise - regular exercise keeps your heart and blood vessels in good condition. It doesn't need to be too energetic - walking every day is enough.
- Eat well - aim to eat a diet that includes plenty of fruit and veg, wholegrains, fat-free or low-fat dairy products and lean proteins. It's a good idea to cut down on salt too. 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.
- Vaccinations - if you have heart disease, it's recommended that you have a flu jab every year and a pneumonia vaccination (also called the pneumococcal vaccine) every 5 years. Ask your doctor about these vaccinations. You can have them free on the NHS.