Blood Thinners Explained: Aspirin, Clopidogrel, Warfarin and Safety Rules

If you take a daily blood thinner, you are in good company. Millions of people use these medicines after a heart attack, a stent, a stroke, an irregular heartbeat or a blood clot in the leg or lung. They save lives, but they also need respect. A missed dose, a new painkiller, a change in diet or a dental extraction can all matter.

This guide explains the two main types of blood thinners, how they work, how to take them safely, the warning signs of bleeding, and what to tell your doctor and dentist.

What is a blood thinner?

Blood thinners do not actually thin the blood. They make it less likely to clot. Clots can block arteries (causing a heart attack or stroke) or veins (causing deep vein thrombosis or a clot in the lungs). There are two main groups.

1. Antiplatelets

These stop platelets, tiny blood cells, from sticking together. They are used mostly to prevent clots in arteries, for example after a heart attack, a stent or a stroke.

• Low-dose aspirin, such as Loprin 75 and Ascard 75.
• Clopidogrel, such as Plavix and Clopid 75.
• Ticagrelor, for example Hitica and Tissara.

2. Anticoagulants

These slow the clotting process itself. They are used for atrial fibrillation (an irregular heartbeat), deep vein thrombosis, pulmonary embolism, artificial heart valves and after some surgeries.

• Warfarin (warfarin) is an older tablet that needs regular blood tests (INR) and has many interactions.
• Direct oral anticoagulants (DOACs) such as rivaroxaban and apixaban. Brands include Rivaro and Oxaban. They need fewer tests and have fewer food interactions, but they still need careful use and kidney checks.
• Heparin and similar injections, used mainly in hospitals, and sometimes for home use.

See the blood thinners category. These are prescription medicines. If you have a prescription, you can upload it here.

The golden rules

• Take it exactly as prescribed, at the same time every day. Blood thinners work for a limited time, so missed doses raise the clot risk quickly.
• Never stop without asking your cardiologist or doctor, even before dental work or surgery. After a stent, stopping an antiplatelet early can cause a dangerous clot in the stent.
• Do not double a dose to make up for a missed one. Read the leaflet, or ask your doctor or pharmacist what to do.
• Do not change brands or add other products without telling your doctor.
• Carry a card or note saying that you take a blood thinner, and list the medicine.
• Keep appointments and blood tests.

Warfarin: special points

• INR tests check how thin your blood is. Your doctor adjusts the dose to keep it in range. Do not skip tests.
• Keep your vitamin K intake steady. Green leafy vegetables such as saag, spinach, methi and broccoli contain a lot. You do not have to avoid them, but eat roughly the same amount each week, and do not suddenly start a green detox or stop eating greens.
• Many medicines interact, including common antibiotics, antifungals and painkillers. Tell your doctor whenever any medicine is started or stopped.
• Be careful with herbal products, including garlic, ginger, ginkgo, turmeric supplements and cranberry in large amounts. They may affect bleeding or INR.
• Alcohol: only light drinking, if at all, and not binge drinking.

DOACs: special points

• Take them at the same time each day, with food if the leaflet says so (for example some rivaroxaban doses).
• Doses depend on your kidney function, age and weight, so tell your doctor about any kidney problem, and have kidney tests at least once a year.
• There are fewer food interactions, but some medicines still interact, including some antifungals, antibiotics and antiepileptics.
• If you forget a dose, check the leaflet for how long a delay is acceptable.

Painkillers: be careful

• Avoid ibuprofen, diclofenac, naproxen and extra aspirin unless your doctor agrees. They raise the risk of bleeding, particularly in the stomach.
• Paracetamol is generally the safer pain medicine for people on blood thinners, but use only as the pack says.
• If you must take both, your doctor may add a stomach-protecting medicine. Read our guide to acidity medicines, which explains an important interaction between clopidogrel and some acid tablets.

Signs of bleeding: when to get help

Go to the emergency department, or call an ambulance, if you have:

• Bleeding that does not stop after ten minutes of firm pressure.
• Vomiting blood, or vomit that looks like coffee grounds.
• Black, tarry stools, or red blood in the stool.
• Blood in the urine (pink, red or brown urine).
• A severe headache, confusion, weakness on one side of the body, or difficulty speaking. This can mean bleeding in the brain.
• A serious fall or a blow to the head, even if you feel fine. Bleeding can start later.
• Coughing up blood, or severe belly or back pain.

See your doctor soon for frequent nosebleeds, bleeding gums, large bruises that appear without injury, very heavy periods, or unusual tiredness and paleness. Read our guide to iron deficiency, which can result from slow, hidden bleeding.

Everyday safety tips

• Use a soft toothbrush and an electric razor. See our guide to bleeding gums.
• Wear shoes with grip, keep floors clear and well lit, and use handrails, to prevent falls, especially for older people.
• Take care in the kitchen, and wear gloves in the garden.
• Avoid contact sports and high-risk activity.
• Tell your dentist, surgeon and all doctors that you take a blood thinner before any procedure, injection or extraction.
• Keep your blood pressure under control. Read about high blood pressure in Pakistan.

Pregnancy

Warfarin and DOACs can harm an unborn baby. Women who may become pregnant must discuss it with their doctor before starting. Do not stop your tablets on your own, as some women need injections during pregnancy instead.

Related reading

If you take blood thinners for the heart, see our guide to angina and heart medicines and statins and cholesterol.

Frequently asked questions

Can I take aspirin on my own to thin my blood?

Not without a doctor’s advice. Aspirin has benefits for some people and clear risks of bleeding for others.

Can I eat saag if I take warfarin?

Yes, in steady amounts. The key is consistency.

What if I need a tooth extraction?

Tell your dentist. Many procedures can be done without stopping the medicine. Never stop it on your own.

Do I need blood thinners for life?

It depends on the reason. Some people need them for a few months, others for life. Your doctor reviews this regularly.

Order prescribed blood thinners from Khasmart, with delivery across Pakistan.

This article is for general information and is not a substitute for advice from your doctor or cardiologist. It does not include doses; your doctor decides the medicine and amount. In an emergency, go to the nearest hospital.