The UK National Institute for Health and Care Excellence (NICE) has released guidelines for the management and monitoring of hyperthyroidism in adults. According to the recommendations, published in a guideline summary in BMJ, the use of radioactive iodine resulted in the cure of as many as 90% of hyperthyroidism cases. Existing conventional recommendations are to treat patients with antithyroid drugs called thionamides, and in the UK and Europe radioactive iodine is often only given if they suffer a relapse after this treatment.

The guideline lay heavier emphasis on the use of radioactive iodine as the frontline treatment for patients unlikely to remain remission-free on the medications, as opposed to the alternative of antithyroid medications as a first choice. Thyroid disease, comprising thyroid dysfunction and enlargement, is common and often identified in primary care. Conditions causing thyroid dysfunction can be broadly divided into those that result in thyroid gland underactivity (overt and subclinical hypothyroidism) or overactivity (thyrotoxicosis). Hypothyroidism is usually managed by general practitioners.

Key recommendations include: A starting levothyroxine dose of 1.6 μg/kg/day (rounded to the nearest 25 μg) is recommended for adults under 65 years old with primary hypothyroidism and no history of cardiovascular disease. A starting levothyroxine dose of 25-50 μg/day with titration is recommended for adults aged 65 and over and adults with a history of cardiovascular disease. Natural thyroid extract is not recommended and liothyronine (alone or in combination with levothyroxine) is not routinely recommended for treating people with primary hypothyroidism. Aim to maintain thyroid-stimulating hormone (TSH) levels within the reference range when treating primary hypothyroidism with levothyroxine; if symptoms persist consider adjusting the dose of levothyroxine further to achieve optimal wellbeing, but avoid using doses that cause TSH suppression or thyrotoxicosis. Radioactive iodine is recommended as first-line treatment for thyrotoxicosis with hyperthyroidism unless antithyroid drugs are likely to achieve remission or it is unsuitable.

“Our evidence reviews indicated that radioactive iodine is the most clinically and cost-effective treatment for hyperthyroidism,” senior author Kristien Boelaert, MD, PhD, who led the guideline committee, told Medscape Medical News. “Recommending the use of radioactive iodine as first-line treatment for adults with Graves’ disease is a change to current practice and should reduce the variation between centres as to when radioactive iodine is considered appropriate,” the guidelines further state. Individuals treated with radioactive iodine take a single tablet that contains iodine and a low dose of radiation, which is absorbed by the thyroid. After taking the treatment patients are advised to avoid prolonged close contact with children and pregnant women for a few days or weeks and avoid getting pregnant or fathering a child for several months. The treatment is likely to lead to an underactive thyroid gland which will require ongoing treatment with thyroid hormone tablets. Current guidelines in the UK and Europe typically call for radioactive iodine to be reserved for use as a definitive treatment only after relapse following antithyroid medication treatment. The latest European Thyroid Association guidelines were published in 2018.

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