EFFECT OF THE COMBINATION OF DEXAMETHASONE AND SODIUM IPODATE ON SERUM THYROID-HORMONES IN GRAVES-DISEASE
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Date
1983
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Abstract
To investigate the effect of the combination of dexamethasone (Dex) and sodium ipodate (SI) on hyperthyroidism, 24 patients with typical Graves'' disease, divided into 4 groups of 6 persons each were studied. Three groups (Study I) were studied acutely (24 h) to determine the effects of Dex (5 mg every 12 h i.m.), SI (1 oral dose of 3 g) and both drugs at the same doses, upon T4, T3 and rT3 [thyroxine, triidothyronine and reverse triiodothyronine] at 0900 h before therapy was started and 24 h later. The group on Dex and that on SI had a similar T3 decrement of 25.9 .+-. 4.0% and 35.8 .+-. 5.0%, respectively, (P < 0.05), whereas the effect of both drugs combined was greater (64.2 .+-. 3.6%; P < 0.01, Dex, and P < 0.01, SI, respectively). The increment of rT3 was markedly greater in those patients on SI than in those on Dex (561 .+-. 149.2% and 58.9 .+-. 11%, respectively, P < 0.025). A 4th group (Study II) was studied for 7 days while receiving both Dex (1 mg orally 3 times per day) and SI (500 mg orally 3 times per day). Both T4 (from 18.8 .+-. 1.1 to 13.1 .+-. 1.1 .mu.g/dl, P < 0.02) and T3 (from 593 .+-. 41 to 136.3 .+-. 12.7 ng/dl, P < 0.001) decreased at day 8. The initial brisk increment of rT3 at 24 h (808 .+-. 149%, P < 0.005) then diminished concomitantly with the fall of its precursor, T4. The pulse rate correlated with plasma T3 concentration (r = 0.67, P < 0.001) and varied from 104.7 .+-. 3.9 on day 1 to 77.3 .+-. 3.0 beats/min (P < 0.001) on day 4 and then remained stable. Dex and SI have potent inhibitory effects at the level of peripheral conversion of T4 and on the thyroid gland itself and the combined use of these drugs significantly increases these effects. Considering the rapid clinical improvement of thyrotoxicosis achieved with both drugs, this regimen may be valuable in the initial treatment of some patients.