Alternating TSH and Minocycline

[vega1318]

I am a 31yo F, healthy who's been on Dynacin (minocycline) 100mg every day on and off for a year.  My thyroid function tests have been normal as recently as 2 yrs ago.   However, I had them repeated this year (routinely) and TSH was 0.09 with T3 and T4 smack within normal range.  3 weeks later, these were repeated and TSH was now 7.69 with T3 and T4 still normal.  I stopped Minocycline about 1 week prior to the second test (just in case) since there were some reports of thyroid dysfunction after long-term minocycline use.  I am not really symptomatic, if anything I'm a bit overweight (but not gaining rapidly) and sometimes my feet get cold at night.  But this has been going on for years.  

Incidentally, 20 yrs ago, I was within 80mi or so of Chernobyl when it blew up...   who knows..

Any ideas if minocycline could be the culprit?  And if not, what further testing would you suggest?

Appreciate your response!!!

[Mark Lupo, M.D.]

Minocycline is not a common thyroid dysruptor.  Would test thyroid antibodies and with the probable radiation exposure at age 11 would definitely get a thyroid ultrasound.  No treatment yet -- would establish a pattern of thyroid function first.

[vega1318]

Thanks for your feedback.   I am looking into that possibility as well.