Unexpected Effect of Furosemide on Radioiodine Urinary Excretion in Patients with Differentiated Thyroid Carcinomas Treated with Iodine 131

Abstract

Our results demonstrated that furosemide given as an adjuvant medication in patients with DTC causes a significant decrease in urinary excretion of radioiodine and its higher blood concentration. Therefore, furosemide should not be recommended as an adjuvant therapy to radioiodine ablation in patients with DTC previously iodine depleted by low-iodine diet.

Estimation of the Release Time from Isolation for Patients with Differentiated Thyroid Cancer Treated with High-dose I-131

“…However, Matovic et al [13] recently reported that blood radioactivity was greater in patients who received furosemide than in controls, even though the patients who received furosemide passed larger volumes of urine. The mechanism responsible for this paradoxical effect is unknown.…”

The SNMMI Practice Guideline for Therapy of Thyroid Disease with 131I 3.0

“…Outcome studies on this approach are unavailable, and the half-life of thyroxine, about 7 d in a euthyroid patient, makes this recommendation of uncertain value. The use of a diuretic to reduce body iodine content is not advised because of the side effects of hypokalemia and hypotension and because furosemide causes a decrease in urinary iodide excretion and higher blood concentration (63).…”

Preparing Patients for Radioiodine Treatment: Increasing Thyroid Cell Uptake and Accelerating the Excretion of Unbound Radioiodine

“…Some of them point to the fact that this diuretic influences the acceleration of iodine urinary excretion leading to iodine depletion. However, in one of our previous studies (Matovic et al, 2009a) it has been unmistakably shown that this diuretic, in combination with low iodine diet, slows down the elimination of radioiodine in patients treated with this radionuclide (figure 1. and figure 2. ).…”

“…Some researches have shown that the effects of low iodine diet can include an increased iodine retention, instead of iodine depletion, especially if it is combined with the application of diuretics (Hamburger, 1969;Norfray & Quinn, 1974;Tepmongkol, 2002, Matovic et al 2009a). …”