The objective of this study was to determine side-effects associated with
iodized oil injection in patients with
simple goiter. In an
iodine-deficient population, 3420 patients with
simple goiter, who were not taking supplemental
iodine, were chosen for this study. They received a single
intramuscular injection of 1 ml
iodized oil, containing 480 mg
iodide. Clinical and laboratory evaluations were performed every 3 months for one year and every 6 months for the next 4 years. The incidence of hypo- and
hyperthyroidism was 0.6% each, with equal prevalence in both sexes. Most cases of hypo- and
hyperthyroidism were observed during the first 5 months after the injection. Eight cases of
hyperthyroidism were asymptomatic. A further 8 patients had overt
thyrotoxicosis and required treatment with
methimazole for 18 months. Recurrence of
hyperthyroidism was observed in one patient. Five hypothyroid patients were diagnosed only by abnormal thyroid function tests, and 4 cases needed no treatment. Others received T4 treatment for a mean of 14.5 months. Among 14 T4-treated patients, recurrence of
hypothyroidism occurred in 7 patients
after treatment was discontinued. Twenty-nine patients (0.8%) were afflicted with dermatologic complications. The most common dermatologic side-effect was urticarial reaction. In 15 subjects, skin lesions appeared 8 to 14 days after injection. It is concluded that side-effects of
iodized oil injection are rare, and in most cases the complications are transient and self-limited. The occurrence of
iodine induced
hyperthyroidism following
iodized oil administration is close to the ratio observed in spontaneous
thyrotoxicosis.