Pulmonary embolism

Patient education is essential before starting warfarin. Patients should be informed about the proper use of warfarin, the need for a regular blood clotting test (INR), and the need for regular follow-up.

Patients should be aware that:

• Warfarin stops the blood from clotting too easily (it 'thins' the blood).

• Warfarin can cause bleeding. Patients should be made aware of the signs and symptoms of bleeding.

• Warfarin dose can vary with the day of the week (e.g., 4 mg on Monday, Wednesday, Friday, and Sunday; 5 mg on Tuesday, Thursday, and Saturday).

• If a warfarin dose is missed, it should be taken as soon as the patient remembers.

• Planned daily doses should be written down, and a note made after the dose is taken. A pill organiser can help the patient to remember when, and how often, to take their warfarin.

• A blood clotting test (the INR) may need to be done several times a week.

• The target INR values are generally between 2 and 3 or 2.5 and 3.5.

• Foods containing large amounts of vitamin K (e.g., spinach, broccoli) can interfere with the effect of warfarin. Eating any amount of vegetables or greens is acceptable, so long as the intake is consistent from week to week.

• Warfarin interacts with lots of other medicines. Patients should ask the healthcare professional who oversees their warfarin therapy, or a pharmacist, to see if it is safe to take a new medicine. They should also speak to their healthcare professional if a current medicine is stopped.

Patients should also be educated before beginning direct-acting oral anticoagulants (DOACs). Patients should be aware that:

• DOACs also stop the blood from clotting too easily (they 'thin' the blood) and can cause bleeding. Patients should be made aware of the signs and symptoms of bleeding.

• Medications are taken orally, once or twice a day depending on which medication has been prescribed.

• Apixaban, dabigatran, and edoxaban can be taken with or without food. Rivaroxaban should be taken with a meal.

• Patients who have concerns about using animal products because of religious or ethical beliefs or a food intolerance should be aware that apixaban and rivaroxaban contain lactose from cow's milk.

• Tablets should be swallowed whole with water. Unlike warfarin, there are no dietary restrictions with DOACs. DOACs also interact with fewer medicines.