From the Guidelines
Hyperthyroidism should be treated with antithyroid medications, such as methimazole, or nonreversible thyroid ablation therapy, particularly for patients with a TSH level that is undetectable or less than 0.1 mIU/L, especially those with overt Graves disease or nodular thyroid disease 1.
Causes and Risk Factors
Hyperthyroidism is a condition where the thyroid gland produces excessive thyroid hormones, causing an accelerated metabolism. The most common causes of hyperthyroidism include Graves disease, Hashimoto thyroiditis, and functional thyroid nodules. Risk factors for a low TSH level include female sex, advancing age, black race, low iodine intake, personal or family history of thyroid disease, and ingestion of iodine-containing drugs, such as amiodarone.
Treatment
Treatment typically begins with antithyroid medications like methimazole (starting at 10-30 mg daily) or propylthiouracil (100-300 mg daily in divided doses), which block hormone production. Beta-blockers such as propranolol (20-40 mg every 6-8 hours) can help manage symptoms like rapid heart rate and tremors while waiting for antithyroid medications to take effect.
- Treatment usually continues for 12-18 months, with regular monitoring of thyroid function every 4-6 weeks initially, then every 2-3 months once stabilized.
- For patients who don't respond to medication or experience recurrence, radioactive iodine therapy or thyroid surgery may be necessary.
Important Considerations
- Patients should be aware that symptoms may worsen initially during treatment and should report any signs of infection, unusual bleeding, or skin rash, which could indicate medication side effects.
- Regular follow-up is essential as some patients may eventually develop hypothyroidism requiring thyroid hormone replacement.
- The American Association of Clinical Endocrinologists Medical Guidelines for the Evaluation and Treatment of Hyperthyroidism and Hypothyroidism have discussed the use of beta-blockers in conditions characterized by an excess of thyroid hormones without specifically recommending one beta-blocker over another 1.
From the FDA Drug Label
Once clinical evidence of hyperthyroidism has resolved, the finding of a rising serum TSH indicates that a lower maintenance dose of methimazole should be employed. Once clinical evidence of hyperthyroidism has resolved, the finding of an elevated serum TSH indicates that a lower maintenance dose of propylthiouracil should be employed.
The treatment for hyperthyroidism involves the use of antithyroid medications such as methimazole and propylthiouracil.
- The goal of treatment is to reduce thyroid hormone production to normal levels.
- Thyroid function tests should be monitored periodically during therapy to adjust the dose of medication as needed.
- When clinical evidence of hyperthyroidism has resolved, a lower maintenance dose of the medication should be employed, as indicated by a rising or elevated serum TSH level 2 3.
From the Research
Treatment Options for Hyperthyroidism
- Medical treatment of Graves' hyperthyroidism is based on the use of thionamides, namely methimazole and propylthiouracil 4
- Thionamides are effective for short-term control of Graves' hyperthyroidism, but a relatively high proportion of patients relapse after thionamide withdrawal 4, 5
- Other possible medical treatments include iodine and compounds containing iodine, perchlorate, lithium, β-adrenergic antagonists, glucocorticoids, and some new molecules still under investigation 4, 6
Comparison of Methimazole and Propylthiouracil
- Methimazole 30 mg/d normalized serum free T4 in more patients than propylthiouracil 300 mg/d and methimazole 15 mg/d at 12 weeks 7
- Adverse effects, especially mild hepatotoxicity, were higher with propylthiouracil and significantly lower with methimazole 15 mg/d compared with methimazole 30 mg/d 7
- Methimazole 15 mg/d is suitable for mild and moderate Graves' disease, whereas methimazole 30 mg/d is advisable for severe cases 7
Treatment Protocols for Primary Care Providers
- A straightforward protocol for the treatment of Graves' hyperthyroidism using methimazole has been shown to be effective in primary care settings 8
- The protocol involves initial doses and up-titration based on free T4 and free T3 concentrations and down-titration by free T4 and TSH concentrations 8
- The protocol rapidly reversed hyperthyroidism in most patients, with 72% achieving euthyroidism at the end of the study 8
Non-Thionamide Antithyroid Drug Options
- Non-thionamide alternatives are occasionally indicated in patients who are intolerant or unresponsive to thionamides alone 6
- Established non-thionamide agents include iodine compounds, potassium perchlorate, lithium, glucocorticoids, beta-blockers, and cholestyramine 6
- Novel experimental agents in development target key players in Graves' disease pathogenesis, including B-cell depletors, CD40 blockers, TSH-receptor antagonists, blocking antibodies, and immune-modifying peptides 6