I have been on levothyroxine for 10+ years and never had a problem (well not since the early years) - I have been getting along nicely on a dose of 75 for the last few years. I was at the GP's a few weeks ago about something not related to my thyroid and happened to mention in the conversation that I got tired easily. The GP then said that as I was on a low dose of thyroxine I should go up to 125 to see how it went. I did and found I had more energy but regularly got very easily 'twitchy' and had to get up and walk around and felt anxious a lot? I then had a blood test at her request to see how things were going:
Thyroid function test
Serum TSH level 0.03 mU/L [0.3 - 5.0]; Below low reference limit
Serum free T4 level 15.7 pmol/L [7.9 - 16.0]
Serum total 25-hydroxy vitamin D level 141 nmol/L [75.0 - 250.0]; Between 76 and 150 nmol/L: Vitamin D sufficient.
Serum ferritin level 34 ug/L [15.0 - 300.0]; Ferritin >15 and <100 ug/L. With low Hb and MCV,
a normal ferritin in the presence of inflammatory
changes does not exclude iron deficiency.
I was then told my levels were too low/high and to reduce to 100. I did that but after a couple of days I woke up (I take my levo at night) and couldn't walk round the house without holding onto the furniture I was so dizzy. This lasted about 2 hours then slowly wore off. Next morning the same thing happened so I decided not to take any levo that night. Third morning I was just slightly dizzy, now it has gone away totally. However, at the moment I am taking 25 one night then 50 the next and don't feel great. I will go back to 75 from tonight but I am curious - do the results above indicate that 125 was too high and do you think the dizziness was something to do with that or totally unrelated?