Indian Journal of Nuclear Medicine

LETTER TO THE EDITOR
Year
: 2018  |  Volume : 33  |  Issue : 1  |  Page : 84--85

Absence of iodine/iodide in cough/expectorant medications: A true disclaimer or not?


Ramya Sugumar1, Subramanian Kannan2, Adlyne Reena Asirvatham3, Shriraam Mahadevan3,  
1 Department of Pharmacology, Sri Ramachandra University, Chennai, Tamil Nadu, India
2 Department of Endocrinology, Mazumdar Shaw Medical Centre, Narayana Health, Bengaluru, Karnataka, India
3 Department of Endocrinology, Sri Ramachandra University, Chennai, Tamil Nadu, India

Correspondence Address:
Dr. Shriraam Mahadevan
Department of Endocrinology, A1, Private Clinic, Sri Ramachandra Medical Centre, Porur, Chennai - 600 116, Tamil Nadu
India




How to cite this article:
Sugumar R, Kannan S, Asirvatham AR, Mahadevan S. Absence of iodine/iodide in cough/expectorant medications: A true disclaimer or not?.Indian J Nucl Med 2018;33:84-85


How to cite this URL:
Sugumar R, Kannan S, Asirvatham AR, Mahadevan S. Absence of iodine/iodide in cough/expectorant medications: A true disclaimer or not?. Indian J Nucl Med [serial online] 2018 [cited 2019 Dec 15 ];33:84-85
Available from: http://www.ijnm.in/text.asp?2018/33/1/84/223237


Full Text



Sir,

Iodine is an essential micronutrient required by all individuals for health and well-being. Iodine serves a crucial role in thyroid physiology by being both a key component of thyroid hormones and by regulating thyroid gland function. The thyroid gland concentrates iodine by an adenosine triphosphate-dependent carrier-mediated mechanism against an electrochemical gradient, and this process is regulated by thyroid-stimulating hormone (TSH). TSH stimulates while excess iodine inhibits all the consequent steps in thyroid hormone biosynthesis, from oxidation and organification of iodide to the secretion of thyroxine and tri-iodothyronine into the circulation.[1]

Radioactive iodine (I 131) is selectively taken up by thyroid, incorporated into iodoamino acids, and deposited in the follicular colloid. The thyroid follicles then gradually and slowly release I 131. I 131 emits destructive beta particles from within the follicles causing damage to only thyroid parenchymal cells with minimal influence on surrounding tissue.[1] I 131 is mainly used in the ablation of residual thyroid/metastasis following total thyroidectomy in patients with well-differentiated thyroid cancer. It is also indicated in the treatment of hyperthyroidism in older patients and in those with heart disease, persistent or recurrent Graves' disease after subtotal thyroidectomy, and failure of remission following prolonged treatment with anti-thyroid drugs and in patients with toxic nodular goiter.[1],[2]

During therapy with I 131, patients are recommended to avoid/discontinue the use of iodide-containing preparations, iodine supplements, and other medications that could potentially affect the ability of thyroid tissue to accumulate I 131 for a sufficient time before commencing therapy.[2],[3]

Among the medications containing iodide, are cough/expectorants which are always recommended to be avoided during I 131 therapies. The real question now arises if cough and expectorant medications truly contain iodide. With extensive search in relation to this regard, it was discovered that few of the older cough/expectorant preparations contained iodide/iodine in substantially large quantities, but preparations of the recent times claim not to contain iodine except for one preparation.

[Table 1] summarizes a few important constituents of cough/expectorant combinations prevalent during the late 19th centuries containing iodide. The table also shows some commonly used cough/expectorant combinations during the recent 20th century exhibiting a striking feature of lacking any iodide component in them with one exception.[3],[4]{Table 1}

This preliminary initiative of insight into the iodine/iodide content among the various cough and expectorant medications currently available in contrast to the older preparations may prove valuable to consider precautionary measures during I 131 therapy to avoid potentially significant drug interactions, where presently, all cough/expectorant medications are contraindicated with an assumption of high iodide content in them.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Bahn RS, Burch HB, Cooper DS, Garber JR, Greenlee MC, Klein I, et al. Hyperthyroidism and other causes of thyrotoxicosis: Management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists. Endocr Pract 2011;17:456-520.
2Meier DA, Brill DR, Becker DV, Clarke SE, Silberstein EB, Royal HD, et al. Procedure guideline for therapy of thyroid disease with (131)iodine. J Nucl Med 2002;43:856-61.
3Kastrup EK, Olin BR. Drug facts and comparisons. 1987 1st ed. USA: JB Lippincott Company; 1987. p. 669-822.
4Expectorant, Antitussive, Mucolytics. Available from: http://www.medlineindia.com/respiratory/expectorant.htm. [Last accessed on 2017 May 30].