CHICAGO — Once-weekly levothyroxine administration in hypothyroid women proved to be a safe and well-tolerated alternative to standard daily therapy in a Brazilian randomized trial.
Echocardiographic evaluation showed no differences between the two dosing regimens in terms of cardiovascular function.
And most of the study participants preferred the convenience of once-weekly dosing, Dr. Gisah Carvalho reported at the annual meeting of the American Thyroid Association.
She presented a 12-week, randomized crossover trial in which 19 hypothyroid women spent 6 weeks taking their normal daily levothyroxine dose and another 6 weeks in which they took seven times their regular daily dose once weekly.
Mean serum TSH was significantly higher after 6 weeks of weekly therapy, at 4.41 mIU/L, as compared with 3.38 mIU/L with daily therapy. Free thyroxine was lower: 1.0 ng/dL, as compared with 1.2 ng/dL with daily therapy.
Four hours after once-weekly levothyroxine administration the mean free thyroxine was 1.8 ng/dL, compared with 1.15 ng/dL 4 hours after daily dosing. Total triiodothyronine was unaffected, according to Dr. Carvalho of the Federal University of Paraná, Curitiba, Brazil.
The weekly dosing regimen is particularly appreciated by patients who find adherence to daily therapy challenging.
Dr. Carvalho disclosed no conflicts of interest.