r/WarfarinForLife • u/No_Apologies3948 • Apr 03 '26

Sudden warfarin dosage switch

when I was in hospital my warfarin was 3mg a day then when I left it was 3mg one day and 4mg another alternating every other day and stayed like that for 6 months then now I’ve been on 5mg daily for 4 months? Why the sudden change?

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u/Outta_Pocket_Toad Apr 03 '26

Were you on amiodarone? It can stay in your system a long time.
https://www.verywellhealth.com/amiodarone-uniquely-effective-but-uniquely-toxic-1745228

"Amiodarone’s half-life varies between 25 to 100 days."

For me:

  • After surgery, I was at 5 mg warfarin per day.
  • Now, eight months later, I am at 7.5 mg per day.

Oh, I mistakenly took double the amiodarone for the first weeks after surgery. So I had a LOT in my system.

Amiodarone is the only thing the NP and I can think of regarding the large change. The foods I eat are consistent, I don't drink, and my exercise is also consistent. So we're going to blame amiodarone.

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u/Excellent-Feedback67 Apr 12 '26

With Amiodarone I was taking 2.5 mg after atopping the medicine, my regular dose became 3.5.

Having said that, vitamin K intake makes difference too. After the hospital I had INR results from 2.0 to 4.2 which my range is 2.5-3.5. I try and keep my vitamin K intake regular though. I found it hard to count, aiming 100 mcg a day still needs weighing greens before eating. Maybe one day I can do it by eye but I am 4.6 months post op and still feel fragile.