Twice Weekly L-T 4 for the Treatment of Primary Hypothyroidism

This study was done to see whether levothyroxine (L-T 4) given twice a week is effective and safe in the management of primary hypothyroidism in 20 patients with primary hypothyroidism who were followed by the outpatient clinic, Ankara University Medical School Department of Endocrinology. The patients were euthyroid on their usual once daily L-T 4 treatment. They had neither coronary heart disease nor arrhythmia. Their ages were 20-50 and their mean daily L-T 4 dose was 123.75±29.77 g (100-200). After the initial physical and biochemical evaluation, the patients were put on a twice daily L-T 4 regimen on which they took four times their usual daily dose of L-T 4 on Mondays, and three times that on Fridays. In the tenth week of that twice weekly L-T 4 regimen, the patients were reevaluated. On twice weekly L-T 4, serum mean free T 3 level, (3.78±0.49 vs 4.05±0.47 pmol/L; p=0.02), antithyroglobulin antibody titer (369±679 vs 984±2950 IU/ml; p=0.04), SGOT level (18.75±4.78 vs 22.45±6.42 U/L; p=0.007), creatine phosphokinase level (110.75±25.60 vs 125.94±32.71 U/L; p= 0.04), PEP (50.5±8.41 vs 70.7±16.59 msec; p= 0.03), PEP/LVET ratio (0.202±0.04 vs 0.288±0.09; p= 0.0031), and mean diastolic blood pressure (78.75±6.86 vs 83.25±10.55 mmHg; p= 0.03) were lower. Serum sensitive TSH (3.69±1.32 vs 2.75±0.68 mIU/ml; p= 0.02) and osteocalcin levels (8.03±6.85 vs 3.39±2.32 ng/ml; p= 0.008) and mean pulse rate were higher. Due to the observed effects on heart and bone reminiscing hyperthyroidism, it is hard to accept twice weekly L-T 4 regimen as a suitable form of treatment for hypothyroidism.