Warfarin is a small tablet, but for many patients, it carries a big responsibility.
This medicine is commonly prescribed to prevent harmful blood clots in people with conditions such as atrial fibrillation, deep vein thrombosis, or prosthetic heart valves.
For these patients, warfarin can reduce the risk of stroke and other serious clot-related complications.
However, warfarin is not a medicine to be taken casually. It is not a “take and forget” tablet. It requires regular blood tests, careful dose adjustment, and good understanding of how food, other medicines, supplements, and even traditional products may affect its action.
A useful way to understand warfarin is this: it does not make the blood “thin” like water. Instead, it slows down the blood clotting process. If the effect is too weak, clots may still form.
If the effect is too strong, bleeding may occur. This is why safe warfarin use depends not only on taking the tablet, but also on knowing how to take it correctly.
According to cardiologist Dr Ahmad Fazli Abdul Aziz, newer blood thinners, known as direct oral anticoagulants, are now widely available. For some conditions, such as atrial fibrillation and deep vein thrombosis, these newer medicines are often easier to use because they usually require less routine monitoring and have fewer food interactions.
However, warfarin remains important for certain patients, especially those with prosthetic heart valves. It is also more affordable for many people, although patients still need to attend clinic appointments and blood tests.
For these reasons, warfarin will likely remain an important treatment for many patients.
What Patients Should Not Ignore
The danger with warfarin is not only the medicine itself. The danger is when patients do not know enough about how to take it safely.
Some patients may not know why their dose changes. Some may not realise that painkillers, antibiotics, herbal products, supplements, alcohol, or sudden changes in diet can affect warfarin. Others may not recognise warning signs that need urgent attention.
One important test for warfarin patients is the INR blood test. INR helps show whether the blood is clotting at a safe level.
If the INR is too low, the medicine may not protect enough against clots. If it is too high, the risk of bleeding increases. This is why regular blood monitoring is necessary, even when the patient feels healthy.
Patients should also know what to do if they miss a dose. A common mistake is taking two tablets the next day to “replace” the missed dose. This can be dangerous.
Patients should follow the advice given by their clinic and inform health care professionals if they often forget their medicine.
Food is another area where many patients feel confused. Warfarin patients do not always need to avoid green vegetables completely.
The key is consistency. Sudden major changes in diet, especially foods high in vitamin K, may affect warfarin control. Alcohol, cranberry products, herbal supplements, and traditional remedies may also interfere with the medicine.
Patients should also be alert to warning signs. These include unusual bruising, bleeding gums, nosebleeds that are hard to stop, blood in the urine, black stools, vomiting blood, severe headache, sudden weakness, dizziness, or bleeding that lasts longer than usual after a small cut. These signs should not be ignored.
Before buying any medicine from a pharmacy, patients should always inform the pharmacist that they are taking warfarin. This includes painkillers, cold medicines, supplements, or traditional remedies.
In Malaysia, this message is especially important. Patients come from different languages, cultures, education levels, and health literacy backgrounds. Some may be highly educated but still confused by medical instructions. Others may depend on family advice, traditional beliefs, or information from the internet.
This is where nurses and other health care professionals play an important role. A clear conversation can help patients understand their medicine, ask questions, and feel more confident. Families should also be involved because they can help remind patients about appointments, medication routines, and warning signs.
Warfarin safety should never begin and end with a prescription. Patients need understanding, support, and confidence. Sometimes, one clear conversation can make the difference between taking medicine and taking medicine safely.
Noor Hanita Zaini, Nor Zehan Ahmad, and Noor Hasliza Che Seman are lecturers at the Faculty of Nursing, University of Malaya.
- This is the personal opinion of the writer or publication and does not necessarily represent the views of CodeBlue.
