Warfarin an anticoagulant. We know from large published studies that warfarin may help patients with idiopathic pulmonary hypertension live longer. For other types of PH, the evidence is less clear so the doctors will assess each case for the likely benefits against the risks.
What is warfarin and why is it used in people with PH?
The three main types of warfarin tablet
Dose adjustments with warfarin
People taking warfarin need blood tests every 4–8 weeks. If the blood tests show that warfarin is not working properly, then a different dose will be needed.
The effect of warfarin is measured by the time it takes for a sample of blood to clot. The time it takes for a sample of blood to clot is expressed as a ratio compared with normal blood. This ratio is called the international normalised ratio (INR). If your blood takes twice the normal time to clot, the INR will be 2. In people with PH an INR between 2 and 3 is needed to prevent blood clots.
In people just starting to take warfarin, blood tests may be needed more frequently until the INR becomes stable.
Precautions when taking warfarin
Warfarin reduces the ability of your blood to clot. This means you have to be careful when doing exercise. Even minor injuries or small knocks could result in bleeding or bruising.
You should talk to your doctor straight away, if you experience any of the following while taking warfarin:
- prolonged bleeding from cuts
- bleeding that does not stop by itself
- nose bleeds
- bleeding gums
- red or dark brown coloured urine
- for women, increased bleeding during periods (or any other vaginal bleeding).
Other medicines you may be taking may affect how your warfarin works. This includes medicines bought without a prescription and herbal medicines.
Check with your doctor or pharmacist before starting any new medicines while you are taking warfarin.
Make sure you tell any healthcare professionals that you are taking warfarin. This includes people such as doctors, nurses, dentists, pharmacists, chiropodists, etc.