Preparation with iopanoic acid rapidly controls thyrotoxicosis in patients with amiodarone-induced thyrotoxicosis before thyroidectomy.
BACKGROUND
Amiodarone-induced thyrotoxicosis (AIT) may develop either in apparently normal glands (type II AIT) or in the presence of thyroid abnormalities (type I AIT). Sometimes AIT is resistant to conventional treatment. Thyroidectomy was used in patients with AIT, but in patients who are thyrotoxic it may be hazardous. METHODS; Seven patients with AIT (6 type I and 1 type II, 5 men, 2 women, mean age 70 years [range, 60-82 years]) were prepared for total thyroidectomy with a short course of iopanoic acid (1 g/day orally for a mean of 13 days), an oral iodinated cholecystographic agent inhibiting 5'-deiodinase and causing a reduction in the peripheral conversion of thyroxine to triiodothyronine. Mean thyroid volume was 64 mL (range, 10-145 mL).


RESULTS
Mean serum-free triiodothyronine levels decreased from 20 +/- 16.7 pmol/L to 6 +/- 2 pmol/L (P =.0004), whereas serum-free thyroxine values remained unchanged. Euthyroidism was rapidly (7-20 days) restored, allowing an uncomplicated total thyroidectomy in all patients and the ability to continue amiodarone therapy in 6 patients. None had increased surgical bleeding, recurrent nerve palsy, or hypoparathyroidism. No cardiovascular complications occurred.


CONCLUSIONS
Iopanoic acid is an effective drug allowing rapid control of hyperthyroidism in AIT.
Bogazzi
Fausto
F
Department of Endocrinology and Metabolism, University of Pisa, Cisanello Hospital, Via Paradisa 2, 56124 Pisa, Italy.
Miccoli
Paolo
P
Berti
Piero
P
Cosci
Chiara
C
Brogioni
Sandra
S
Aghini-Lombardi
Fabrizio
F
Materazzi
Gabriele
G
Bartalena
Luigi
L
Pinchera
Aldo
A
Braverman
Lewis E
LE
Martino
Enio
E
D000368:Aged; D000369:Aged, 80 and over; D000638:Amiodarone / Q000009:adverse effects*; D003287:Contrast Media / Q000008:administration & dosage*; D004791:Enzyme Inhibitors / Q000009:adverse effects*; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000139:chemically induced / Q000188:drug therapy; D007480:Iopanoic Acid / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care; D013965:Thyroidectomy; D013971:Thyrotoxicosis / Q000139:chemically induced / Q000188:drug therapy*
D003287:Contrast Media; D004791:Enzyme Inhibitors; D007480:Iopanoic Acid; D000638:Amiodarone