11. letters of editor related to hyperhyroidism

8/9/2019 11. Letters of Editor Related to Hyperhyroidism

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J. Clin. Endocrinol. Metab. 2005 90: 1256, doi: 10.1210/jc.2004-1999

Luigi Bartalena, Fausto Bogazzi, Aldo Pinchera and Enio Martino

Yes or No?Treatment with Thionamides before Radioiodine Therapy for Hyperthyroidism:

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LETTERS TO THE EDITOR

Treatment with Thionamides before Radioiodine

Therapy for Hyperthyroidism: Yes or No?To the editor:

We read with great interest the paper by Bonnema et al. published ina recent issue of the Journal of Clinical Endocrinology and Metabolism (1).This randomized clinical trial showed that the efficacy of radioiodine(RAI) therapy for hyperthyroidism was reduced when RAI was admin-istered after pretreatment with propylthiouracil (PTU) (1). Although theresults of Bonnema et al. are convincing, this effect might be specific forPTU. In fact, two well-designed, prospective, randomized trials (2, 3)failed to show any consequence of methimazole (MMI) pretreatment ontheefficacyof RAItherapy.This difference might be related to thelongerradioprotective effect of PTU. Because data of the literature andour ownexperience indicated that MMI pretreatment does not affect successfulmanagement of hyperthyroidism by RAI therapy, we treat all hyper-thyroid patients with MMI for 23 months before RAI administration torestore euthyroidism and to deplete intrathyroidal iodine stores (4). Inour opinion, this approach is particularly important in patients who areold or have underlying nonthyroidal illness. In addition, prompt cor-rection of hyperthyroidism is required in Graves patients with associ-ated orbitopathy, because restoration of euthyroidism is associated witha more favorable course of eye disease (5).

In the paper by Bonnema et al. (1), as well as in a previous report byBurch et al. (6), RAI therapy was not followed by an increase in serumthyroid hormone concentrations. However, because thyroid functionwas evaluated 3 wk after RAI therapy (1), early and transient changesin serum thyroid hormone levels might have been missed. In addition,the results of Bonnema et al. clearly showed that, when RAI therapy wasgiven, serum thyroid hormone concentrations were markedly higher innonpretreated patients than in pretreated patients (1). Thus, althoughthe interval between randomization and RAI therapy was not specified,

nonpretreated patients were presumably exposed to a longer period ofuncontrolled hyperthyroidism than patients receiving thionamide pre-treatment. As we mentionedearlier,we believe that this is notacceptablein patients whose hyperthyroidism represents a threatening conditionand must be promptly and effectively controlled. Many thyroidologistsare concerned about the consequences of subclinical hyperthyroidism;in our opinion, we should worry even more about the potential unto-ward effects of overt hyperthyroidism. In this regard, we recently dem-onstrated that lithium administration for a few days before RAI therapyand for 2 wk thereafter can effectively prevent the increase in serumthyroid hormone concentrations that follows RAI administrationand/or MMI withdrawal before RAI therapy (7). Lithium adjuvanttherapy was also associated with a prompter goiter shrinkage after RAItherapy (7).

In conclusion: 1) the study by Bonnema et al. (1) demonstrated thatPTU pretreatment is associated with a lower efficacy of RAI therapy, but

MMIdoes notseem to share this effect; accordingly,we support theviewthat MMI pretreatment should be given for a better control of hyper-thyroidism before RAI therapy; 2) uncontrolled hyperthyroidism is anunacceptable and potentially dangerous situation that requires a moreaggressive approach, particularly in at-risk patients; and 3) a shortcourse of lithium adjuvant therapy, shortly before and afterRAI therapy,is helpful to prevent the increase in serum thyroid hormone concen-trations related to RAI therapy and/or thionamidewithdrawal, to obtaina prompter control of hyperthyroidism, and to achieve a more rapidshrinkage of goiter.

Luigi Bartalena, Fausto Bogazzi, Aldo Pinchera, and Enio

MartinoUniversity of Insubria (L.B.), Varese, Italy; and University ofPisa (F.B., A.P., E.M.), Pisa, Italy

References

1. Bonnema SJ, Bennedbaek FN, Veje A, Marving J, Hegedus L 2004 Propyl-thiouracil before 131I therapy of hyperthyroid diseases: effect on cure rateevaluatedby a randomized clinicaltrial. J ClinEndocrinol Metab89:4439 4444

2. Andrade VA, Gross JL,Maia AL 2001 The effect of methimazole pretreatmenton the efficacy of radioactive iodine therapy in Graves hyperthyroidism:one-year follow-up of a prospective, randomized study. J Clin EndocrinolMetab 86:34883493

3. Braga M, Walpert N, Burch HB, Solomon BL, Cooper DS 2002 The effect ofmethimazole on cure rates after radioiodine treatment for Graves hyperthy-roidism: a randomized clinical trial. Thyroid 12:135139

4. Bogazzi F, Martino E, Bartalena L 2003 Antithyroid drug treatment prior toradioiodine therapy for Graves disease: yes or no? J Endocrinol Invest 26:

1741765. Bartalena L, Tanda ML, Piantanida E, Lai A, Pinchera A 2004 Relationship

between management of hyperthyroidism and course of the ophthalmopathy. J Endocrinol Invest 27:288294

6. Burch HB, Solomon BL, Cooper DS, Ferguson P, Walpert N,Howard R 2001The effect of antithyroid drug pretreatment on acute changes in thyroid hor-mone levels after 131I ablation for Graves disease. J Clin Endocrinol Metab86:30163021

7. Bogazzi F,Bartalena L,Campomori A,BrogioniS, TrainoC, DeMartinoF, RossiG, Lippi F, Pinchera A, Martino E 2002 Treatment with lithium prevents serumthyroid hormone increase after thionamide withdrawal and radioiodine therapyin patients with Graves disease. J Clin Endocrinol Metab 87:4490 4495

doi: 10.1210/jc.2004-1999

Authors Response: Treatment with Thionamides

before Radioiodine Therapy for Hyperthyroidism:

Yes or No?

To the editor:

We thank Bartalena et al. (1) for their comment. The main purpose ofour study(2) was to clarify whether propylthiouracil impairs the efficacyof radioiodine therapy in hyperthyroid diseases. It may be true that thisfeature of propylthiouracil is unique among the antithyroid drugs avail-able, perhaps due to the larger doses of propylthiouracil needed tocontrol the hyperthyroidism. We fully agree with Bartalena et al. thatuntreated hyperthyroidism may have serious health consequences. Therisk of developing heart arrhythmias and osteoporosis are well known.However, it is not elucidated by large controlled studies whether hy-perthyroidism results in irreversible physical or mental impairmentdespite attainment of euthyroidism. Nevertheless, we believe, probablyin agreement with most other physicians, that euthyroidism should beobtained as soon as possible when overt hyperthyroidism is detected.Treatment of hyperthyroidism can be achieved by antithyroid drugs,

radioiodine, or surgery. Obviously, total thyroidectomy with subse-quent l-thyroxine substitution is a very quick way to restore euthy-roidism, but this method is rarely the first choice (3). Therefore, thechoice initially stands between antithyroid drugs and radioiodine. Ahead-to-head comparisonbetween thesetwo methods including an eval-uation of patient satisfaction and the long-term performance has not

been conducted, but indeed this would be relevant. According to sur-veys (3) performed in the early 1990s, physicians do not agree on theprimary therapy of choice. It is evident that both antithyroid drugs andradioiodine are useful for controlling hyperthyroidism, but the time

Received October 11, 2004. Address correspondence to: Prof. Luigi Bar-talena, Department of ClinicalMedicine, Universityof Insubria, Division ofEndocrinology, Ospedale di Circolo, Viale Borri, 57, 21100 Varese, Italy.E-mail: [email protected] or [email protected].

Received November 8, 2004.Address correspondence to: Steen J. Bon-nema, M.D., Ph.D., Department of Endocrinology and Metabolism,Odense University Hospital, DK-5000 Odense C, Denmark. E-mail:[email protected].

0021-972X/05/$15.00/0 The Journal of Clinical Endocrinology & Metabolism 90(2):1256 1257Printed in U.S.A. Copyright 2005 by The Endocrine Society

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11. letters of editor related to hyperhyroidism

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