Combined levothyroxine and iodide in the treatment of diffuse euthyroid goitre: a comparison of two dosages

Background and objective: Administration of levothyroxine and/or iodide can effectively reduce the volume of endemic goitre. However, TSH suppression during levothyroxine treatment may increase the number of recurrences throu gh the persistence of intrathyroidal iodine deficiency. With special attent ion paid to the level of levothyroxine, a comparison was made of two dosage s of combined levothyroxine and iodide. Patients and methods: 44 patients with diffuse euthyroid goitre were random ized to two treatment groups. Group A received 100 mug levothyroxine + 100 mug lodide, group B 75 mug levothyroxine + 150 mug lodide, all of them for three months. This was follwed by three months without the medication. Intr athyroidal iodine concentration was measured at the onset of the study, the n three months and six months later. At these same times thyroid volume was measured by ultrasound, as well as urinary iodine and various parameters o f thyroid function. Results: Thyroid gland Volume was reduced in both groups (group A: -17,3%; group B: -14,8%; p < 0.001). There was no significant difference of intrath yroidal iodine concentration and thyroid volume between both groups. After the treatment period, TSH suppression was more marked in group A, while TSH rise was greater in group B. Conclusions: Both drug combinations resulted in comparable reduction of thy roid volume, while the intrathyroid concentration of iodine remained unchan ged. The smaller rise of TSH after the treatment suggests that the dosage o f 75 <mu>g levothyroxine + 150 mug iodine is to be prefered.