How long does it take Levoxyl (125mg) to be out of your system?

[lacapone]

If I have only been on 125mg of Levoxyl for about a week and I haven't taken any in two days, if I get a blood test for a thyroid condition within the next two days, is the levoxyl still in my system and will it throw off the test results?  Basically how long does it stay in your stystem?

[anacortes]

A related discussion, should I have quit? was started.

[Mark Lupo, M.D.]

It will be in your system for a few weeks -- BUT if you have only been on it for a week - this is too soon for a test -- be consistent with the levoxyl and check in 6 weeks.w

[edra]

My doc told me the half-life of T4 is about 9 days; I've seen other sources that say the half-life is 5-7 days. So, you'd have to wait about a month to make sure the Levoxyl is gone.

The rule of thumb my doc follows on lab testing is: don't do a test until you've been on the same dose a minimum of 6 weeks, and preferably 8 weeks.

[GravesLady]

I wouldn't think that you have been on meds long enough to make a difference.  I never heard of being off of meds for thyroid panel, unless on ATDs or for some other thyroid test, in that case the doctor would have told you the correct procedure to follow.  However if you have been on meds. long enough some say 6 days.  When my Nuc Lab wanted to do another uptake to varify if  RAI worked they wanted me off meds. for 2 months.... I said no way, can't live without my meds. and that was that.  Besides my Labs would reveal my situation.

If you are hypo by whatever means you want thyroid panel done taking meds because you want to know if meds are working at the dose you are on.  If ATDs, I think, you want to know if the thyroid is working therefore meds need to be stopped before the test or that day of the test, then resume taking after test is done.

Labs are done anywhere from 4 to 12 weeeks, depending on your situation.