I am 39yrs taking thyroxine 100mcg 1 tab since 5 years.now tsh 0.22 miu/ml. , total t3, (liothyronine) t4 , freet4 , ft4(serum) are normal.which medicine should i take?

Thyroxine dose: Was your TSH normal before, and now it is low? Over the years, your dose requirements for thyroxine can change, which is why a TSH should be checked periodically. Another possibility: the brand of thyroxine changed. Pharmacies sometimes switch people between different brands to save a few pennies, and there are difference in bioavailability which can affect tsh.