Abstract
Objective: Weekly dosing of thyroxine improves compliance. We aimed to evaluate efficacy and safety of once weekly dosing of thyroxine compared to daily dosing for maintenance therapy of hypothyroidism.
Methods: This is a parallel-group, outcome-assessment-blinded, randomised, controlled clinical trial conducted at a tertiary care hospital in Sri Lanka. Those diagnosed with primary hypothyroidism and have achieved euthyroidism with a stable dose of daily thyroxine for at least 3-months were recruited. Intervention group (IG) received seven times the regular dose once weekly. Control group (CG) received regular dose daily. Echocardiogram, blood pressure (BP), heart rate (HR) and Hyperthyroid Symptom Score (HSS) were assessed 4-6 hours after the first dose of thyroxine and at 12-weeks. Thyroid functions were assessed at 12-weeks.
Results: Number recruited was 32 to IG (women:96.9%;mean-age:47.9±9.2years) & 24 to CG (women: 95.8%;mean-age:50.7±11.2years). Median thyroxine dose was 525mg once weekly in the IG & 75mg daily in the CG. Proportion of patients in euthyroid state at 12-weeks was not different between the groups (IG-84.4%, CG-83.3%, p = 0.57). There was no difference in the thyroid function tests at 12-weeks (mean TSH: IG-2.8μIU/mL, CG-2.1μIU/mL, p=0.348; mean free T4: IG-1.2ng/dL,CG-1.3ng/dL,p=0.445). Safety outcomes at 4-6 hours after first dose were not different between IG and CG (mean end-diastolic diameter:IG-42.1mm,CG-39.9mm,p = 0.14;mean ejection fraction: IG-60.28%, CG-60.33% , p=0.911 ; mean systolic BP : IG-119mmHg , CG-120.8 mmHg , p=0.676; mean HR:IG-75.6bpm,CG-75.4bpm,p=0.261; mean HSS: IG - 3.5/40, CG-4.8/40,p=0.213).IG & CG were comparable regarding safety outcomes at 12-weeks too (mean end-diastolic diameter : IG - 38.9mm , CG - 40.1mm , p = 0.643 ; mean ejection fraction: IG - 59.8% , CG-60% , p=0.429; mean systolic BP:IG-118.8mmHg,CG-116.8mmHg,p = 0.65; mean HR:IG-75.4bpm,CG-75.1bpm,p=0.919;mean HSS:IG-3.6/40,CG-4.1/40,p=0.704).
Conclusions: Weekly dosing of thyroxine is as efficacious and safe as daily thyroxine for maintenance therapy of hypothyroidism. Further research with a larger sample size is recommended.
Published on
08 Dec 2022.
Peer Reviewed
