Warfarin
Blood thinnersAlso known as Coumadin, Jantoven
Warfarin prevents dangerous blood clots by blocking vitamin K, which your body needs to form clots. It protects people with atrial fibrillation, past clots, or mechanical heart valves from strokes. The honest truth: the gap between too little and too much is narrow, and it interacts with a huge list of medicines — check every new one, even antibiotics and supplements, with your pharmacist. And tell every doctor and dentist you see that you take it.
How to take it
When
Once a day, at the same time — many people pick the evening. Consistency is everything with this drug.
Food
Don't avoid leafy greens — just keep your vitamin K intake steady week to week. Sudden diet changes throw off your dose.
Avoid
No ibuprofen or naproxen without asking first. And never stop warfarin on your own, or before a procedure, without the prescribing doctor's OK — clots and strokes are the risk.
Blood tests
Regular INR blood tests are life with this drug — they're how your doctor keeps your dose in the safe zone. Never skip them.
Missed a dose?
Take it as soon as you remember on the same day. If you don't remember until the next day, skip the missed dose and mention it at your next INR check. Never take a double dose.
Common side effects
- Bruising more easily
- Small cuts bleeding a little longer
- Stomach upset
- Hair thinning (uncommon, but it happens)
Call a doctor if
- Blood in your urine or stool, or black tarry stools — get help now
- Coughing or vomiting blood — call emergency services
- Any fall or hit to the head, even if you feel fine — get checked right away; bleeding can be hidden
- Sudden severe headache, weakness, or trouble speaking — call emergency services
- A painful purple toe or a skin sore that's spreading — call your doctor immediately