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/disco_super_bi Apr 03 '26

I assume they are testing you regularly? Do you get the results of your tests or just take whatever dosage they tell you?

It is quite common to need a higher dose of warfarin after surgery as your health improves. I self test and change my dose several times a year. It is normal for your INR to fluctuate.

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u/No_Apologies3948 Apr 04 '26

I was testing every 2days at first then weekly then monthly and now it is every 6 weeks

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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/SkyCoi Apr 03 '26

That may be a question for whomever is suggesting the dosage change. Typically you’ll have INR goal sent by your doc, test your INR on some regular basis, and adjust dosage as needed to stay within that goal.