July - September 2015, Volume 11, Issue 3

Ignjatovic VD, Vukomanovic V, Jeremic M, Ignjatovic VS, Matovic M

Influence of Hydrochlorothiazide on Urinary Excretion of Radioiodine in Patients with Differentiated Thyroid Cancer

Acta Endo (Buc) 2015, 11 (3): 396-400
doi: 10.4183/aeb.2015.396

Objective. After total thyroidectomy, radioiodine (131I) treatment is a usual treatment in patients with differentiated thyroid cancer (DTC). Since most of ingested 131I is excreted by the kidneys, one of the procedures for enhancement of 131I excretion from the body is the use of diuretics. The aim of study was to investigate the effect of hydrochlorothiazide (HCTZ) administration on the excretion of 131I in the urine in patients with DTC treated with 131I. Design. Study included 90 patients with DTC, normal renal function and low 131I uptake in the thyroid gland region. Patients were divided into two groups: the group taking HCTZ and the control group. All patients underwent whole-body measurements of the radioactivity of 131I in the urine and in blood samples. Results. Blood radioactivity was significantly higher in the HCTZ group as compared to the control group (16380.89 vs. 11731.61cpm/mL/GBq; P=0.007). The residual radioactivity in the body and the exposed dose were higher in patients taking HCTZ (71.61 vs. 60.70MBq/ GBq and 7.05% vs. 6.14%) but this difference was not significant. During the first 36h from 131I administration the patients taking HCTZ excreted a higher percentage of the 131I than the controls (65.45±12.12% vs. 62.21±11.25%, P=0.032). During the second part of the hospitalization (36- 72h) the urinary excretion as reversed, so after 72h patients taking HCT excreted less 131I than controls, however, this difference was not significant (P=0.084; 76.54±10.16% vs. 83.81±13.46%). Conclusions. HCTZ given as additional treatment decreases urinary excretion of 131I as and should not be administered in patients under 131I treatment for DTC.

Keywords: DTC, Hydrochlorothiazide, Radiodine-131, Urinary excretion of 131I.

Correspondence: Vladimir Vukomanovic MD, Clinical Center Kragujevac, Department of Nuclear Medicine, Zmaj Jovina street 1, Kragujevac, 34000, Serbia, E-mail: vukomanovic@gmail.com