Effect of pretreatment with carbimazole on early outcome following radio-iodine (131I) therapy

Abstract

Of a group of 55 thyrotoxic patients given therapeutic radio-iodine (131I), 24 were made euthyroid with carbimazole before 131I: the remainder were given 131I alone. Carbimazole was discontinued 5 days before 131I was administered. By 3 months after 131I treatment there was a greater incidence of hypothyroidism in the group given 131I alone (42% vs 25%), but a lower incidence of persistent thyrotoxicosis (16% vs 46%), (P less than 0.05). One year after treatment a similar proportion of each group had persistent thyrotoxicosis (21% vs 23%), but there remained a lower incidence of hypothyroidism in the group pretreated with carbimazole (25% vs 45%). It is suggested that pretreatment with carbimazole reduces the degree of radiation induced thyroid damage.

Two-day Thionamide Withdrawal prior to Radioiodine Uptake Sufficiently Increases Uptake and does not Exacerbate Hyperthyroidism Compared to 7-day Withdrawal in Graves' Disease

“…Moreover, Andrade et al suggested that radioiodine therapy without ATD pretreatment could be safely carried out because serum thyroid hormone levels did not increase by radioiodine administration [1,3]. The possibility that ATD medication reduces the efficacy of radioiodine therapy was also reported [8,11,12,15]. The notion that the majority of patients with Graves' disease do not require ATD pretreatment before radioiodine therapy was supported by several reports [1][2][3]16].…”

“…Various withdrawal periods before radioiodine therapy were reported [7][8][9][10][11][12][13][14]. Sabri et al recommended discontinuing ATD at least 1 day before beginning radioiodine therapy [11,12].…”

“…Many treatment protocols concerning ATD withdrawal periods before radioiodine therapy have been reported [7][8][9][10][11][12][13][14]. Shorter periods may decrease radioiodine uptake (RAIU) and the success rate of therapy.…”

Radioiodine therapy in patients with Graves′ disease and the effects of prior carbimazole therapy

“…[14] Connell et al ., pretreated patients with carbimazole before RAI therapy and discontinued the drug 5 days prior to RAI administration. [15] The treatment failure rate at 1 year follow-up was higher in patients who received prior carbimazole (75% vs 55%) when compared to those who received RAI alone. Andrade et al ., discontinued methimazole 4 days prior to RAI therapy and did not demonstrate any effect on cure rate following RAI therapy.…”

Comparison of two fixed activities of radioiodine therapy (370 vs. 555 MBq) in patients with Graves? disease

“…Carbimazole pre-treatment does not appear to affect the outcome. 21 It has also been suggested that patients with Graves' disease do not require pre-treatment with anti-thyroid drugs. Approximately one fifth of our 555 MBq of radioiodine was no more effective than 370 MBq in managing patients with Graves' disease, we would recommend that the larger activity should not be routinely used in these patients.…”