Decreasing Amiodorone

[Alaska]

Well, I am decreasing my dose of Amiodorone from 400mg a day to 200mg a day. Does anyone know how this will effect my INR (I know I'll need more coumadin)? The cardiologist told my dr that it isn't really the amount of amiodorone - but just that you are on it increases your INR levels. So, I may not need much more coumadin than I'm taking now.

We leave on our trip next Friday - and this is happening JUST when I'm getting a handle on dosing... Wouldn't you know?

[Ross]

That stuff stays in your body for 6 months after you stop it, so I imagine you'll see a slight decrease very gradually. Certainly won't be any immediate thing.

[Alaska]

You are right Ross. I hadn't thought about that! I probably won't see much difference right away...

I was taking 2 mg 5 days a week; and 1mg 2 days a week. The dr told me to go up to 2mg daily, and we will recheck Monday to see what is happening.

[Ross]

Where is your INR now? If it's in range, there is no need to increase it. A decrease in Amiodarone is going to likely show as a decrease in your INR also, but not for weeks yet.

[Alaska]

I was at 2.9 (my machine); 2.6 (their machine) on Wednesday (range 2to3). She doesn't want it to go too low, so we will see what it is like on Monday. She may end up putting me back on the same dose - and then I'll have to deal with it while I'm gone (yikes) as it slowly makes my INR go down.

[DrAllan]

Amiodorone blocks the metabolism of warfarin, thus for any given dose of Coumadin, it stays around longer in the body and thus potentiates its anticoagulant effect. Thus to maintain the same INR when going on amiodorone you must decrease your Coumadin dosage and conversely when going off the drug you must increase the dosage. However, the clearance of amiodorone from the body (mainly the fat and muscle stores) is not the same as the relatively immediate blood level effects from an oral dose. Thismay cause a relatively immediate effect which differs from Ross’s statement.

Just a semantic observation, but amiodorone does not change the INR, it only affects it indirectly by changing the metabolism of the Coumadin itself.

[Alaska]

Thanks for the info. I'll just have to monitor my INR more frequently I guess!