Hyperthyroidism medical therapy
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Hyperthyroidism Microchapters |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
The major and generally accepted modalities for treatment of hyperthyroidism in humans involve initial temporary use of suppressive thyrostatics medication, and possibly later use of permanent surgical or radioisotope therapy. All approaches may cause under active thyroid function (hypothyroidism) which is easily managed with levothyroxine supplementation.
Medical Therapy
Thyrostatics
Thyrostatics are drugs that inhibit the production of thyroid hormones, such as carbimazole (used in UK) and methimazole (used in US), or where these are not tolerated then propylthiouracil is used. Thyrostatics are believed to work by inhibiting the iodination of thyroglobulin by thyroperoxidase.
If too high a dose is used in pharmacological treatment, patients can develop symptoms of hypothyroidism.
Beta-blockers
Beta-blockers do not treat, but rather mask, common symptoms of hyperthyroidism such as palpitations, trembling, and anxiety. Propranolol in the UK, and Metoprolol in the US, are most frequently used to augment treatment for hyperthyroid patients.
Radio-active Iodine
In Iodine-131 (Radioiodine) Radioisotope Therapy, radio-active iodine is given orally (either by pill or liquid) on a one-time basis to destroy the function of a hyperactive gland. The iodine given for ablative treatment is different from the iodine used in a scan. Radio-active iodine is given after a routine iodine scan, and uptake of the iodine is determined to confirm hyperthyroidism. The radio-active iodine is picked up by the active cells in the thyroid and destroys them. Since iodine is only picked up by thyroid cells (and picked up more readily by over-active thyroid cells), the destruction is local, and there are no widespread side effects with this therapy. Radio-active iodine ablation has been safely used for over 50 years, and the only major reasons for not using it are pregnancy and breast-feeding.
Often, due to the difficulty of picking the correct dose, the treatment results in an opposite condition - hypothyroidism. This is considered uncommon since the radioiodine has more affinity towards over-active thyroid cells than it does for the normal ones.
Contraindicated medications
Hyperthyroidism is considered an absolute contraindication to the use of the following medications: