+ Site Statistics
References:
54,258,434
Abstracts:
29,560,870
PMIDs:
28,072,757
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

The effect of propylthiouracil on subsequent radioactive iodine therapy in Graves' disease



The effect of propylthiouracil on subsequent radioactive iodine therapy in Graves' disease



Clinical Endocrinology 47(4): 425-430



OBJECTIVE. Antithyroidal drugs (ATD) are used in the management of Graves' disease either as primary therapy for several months while awaiting remission of the disease or as pretreatment for several weeks prior to definitive radioactive iodine therapy (RAI). We have reported previously that pretreatment with propylthiouracil (PTU) before definitive RAI therapy is associated with a higher RAI treatment failure rate than RAI therapy alone. The objectives of the current study were 2-fold. First, to verify the results of our prior study regarding the effect of PTU used as pretreatment before RAI in a cohort of patients from a different institution and, secondly, to better define the relationship between the number of days off PTU before RAI therapy and therapeutic efficacy of RAI dosing. DESIGN. A retrospective review of Graves' disease patients treated from 1980 to 1994. PATIENTS. Study patients had to meet the following inclusion criteria: radionuclide studies and thyroid hormone values consistent with Graves' disease, at least 1 year of follow-up data available and discontinuation of the ATD at least 4 days before RAI administration. Exclusion criteria included therapy with any ATD other than PTU or ATD therapy during or following RAI dosing. MEASUREMENTS. Effectiveness of RAI therapy, days on PTU, days off PTU and calculated RAI dose to the thyroid were recorded for each subject. We compared the efficacy of RAI therapy in patients treated with PTU (used either as pretreatment in preparation for RAI therapy or as primary long-term therapy) before RAI administrations to those treated with RAI alone with special attention to the number of days on and off PTU before RAI dosing. Patients were considered RAI treatment failures if a second dose of RAI was required to achieve a euthyroid or hypothyroid state. RESULTS. One hundred and sixteen patients met our study criteria. Forty patients received PTU therapy for a mean of 221 +- 59 days. The PTU was discontinued for a mean of 60 +- 25 days before RAI dosing. Persistent hyperthyroidism was seen in 9% (7/76) of patients treated with RAI alone. The failure rate of a single dose of radioactive iodine was significantly increased when PTU was discontinued between 4 and 7 days before the administration of RAI (29% vs 9% for RAI alone, P = 0.039). PTU discontinued for at least 1 week before RAI dosing was associated with a nearly 2-fold increase in failure rate, but this difference did not achieve significance (17% vs 9% for RAI alone, P = 0.24). Examining only those patients receiving PTU, patients who had successful single dose RAI therapy tended to receive a higher dose of RAI than patients failing RAI therapy (480 +- 30 vs 410 +- 40 MBq administered dose, P = 0.18; and 8.0 +- 0.9 vs 5.5 +- 1.1 MBq/g thyroid tissue calculated dose, P = 0.21). Furthermore, total serum thyroxine at diagnosis was significantly higher in patients failing RAI therapy after PTU administration than in patients successfully treated with RAI after receiving PTU (316 +- 40 vs 225 +- 13 nmol/L, P = 0.03). CONCLUSIONS. Propylthiouracil discontinued 4-7 days before radioiodine dosing is associated with a significant increase in the failure rate of a single dose of radioiodine. Discontinuation of the propylthiouracil for at least a week before radioiodine administration is associated with a higher, although not statistically significant, radioiodine failure rate. In patients that require treatment with propylthiouracil before radio-iodine therapy, a higher total serum thyroxine level at diagnosis is associated with an increased rate of radioiodine failure. Consideration should be given to increasing empirically the dose of radioiodine administered to Graves' disease patients that have received propylthiouracil within a week of radioiodine administration in an effort to decrease the radioiodine failure rate to an acceptable level.

Please choose payment method:






(PDF emailed within 0-6 h: $19.90)

Accession: 009565909

Download citation: RISBibTeXText

PMID: 9404440

DOI: 10.1046/j.1365-2265.1997.2741075.x


Related references

Treatment with propylthiouracil before radioactive iodine therapy is associated with a higher treatment failure rate than therapy with radioactive iodine alone in Graves' disease. Thyroid 5(4): 243-247, 1995

Radioactive iodine in the study of thyroid physiology; the use of radioactive iodine therapy in Graves' disease. Western Journal of Surgery, Obstetrics, and Gynecology 54(12): 474-486, 2011

Adjunctive treatment with propylthiouracil or iodine following radioiodine therapy for Graves' disease. Thyroid 3(4): 269-272, 1993

Short-term effect of radioactive iodine therapy on CXCL-10 production in Graves' disease. Clinical and Investigative Medicine. Medecine Clinique et Experimentale 34(5): E262, 2012

Influence of propylthiouracil and methimazole pre-treatment on the outcome of iodine-131 therapy in hyperthyroid patients with Graves' disease. Journal of International Medical Research 37(2): 576-582, 2009

Influence of an additional application of iodine-127 on the pharmacokinetics of radioactive iodine-131 during a radioiodine therapy in patients with Graves disease. Journal of Nuclear Medicine 44(5 Supplement): 332P-333P, 2003

Thyroid Isthmus Length and Iodine Turnover as Predictors of Successful Radioactive Iodine Therapy in Patients with Graves' Disease. International Journal of Endocrinology 2017: 7354673, 2018

No impact of dietary iodine restriction in short term development of hypothyroidism following fixed dose radioactive iodine therapy for Graves' disease. Indian Journal of Endocrinology and Metabolism 19(1): 60-65, 2015

Hyperparathyroidism after radioactive iodine therapy for Graves disease. Surgery 92(5): 811-813, 1982

Outcome following radioactive iodine therapy in Graves' disease. Changgeng Yi Xue Za Zhi 13(4): 258-267, 1990

The late effect of subtotal thyroidectomy and radioactive iodine therapy on calcitonin secretion and bone mineral density in women treated for Graves' disease. Surgery 100(6): 1142-1149, 1986

Radioactive Iodine As An Indicator In Thyroid Physiology. V. The Use Of Radioactive Iodine In The Differential Diagnosis Of Two Types Of Graves' Disease. Journal of Clinical Investigation 21(1): 31-32, 1942

Radioactive Iodine Therapy vs. Antithyroid Medications for Graves Disease. American Family Physician 95(5): 292-293, 2018

Thyroid carcinoma after radioactive iodine therapy for Graves' disease. World Journal of Surgery 18(4): 518-521, 1994

Radioactive iodine therapy for Graves' disease in childhood and adolescence. Arquivos Brasileiros de Endocrinologia E Metabologia 48(1): 166-170, 2004