From the Guidelines
In acute illness, hyperthyroidism should generally not be treated unless there are severe symptoms or thyroid storm, and the recommended approach is to monitor thyroid function closely and treat the underlying acute illness as the priority. The management of hyperthyroidism in acute illness involves a careful balance between controlling symptoms and avoiding unnecessary treatment that could lead to complications. According to the American Association of Clinical Endocrinologists Medical Guidelines for the Evaluation and Treatment of Hyperthyroidism and Hypothyroidism, as discussed in the context of beta-blocker treatment 1, beta-blockers such as propranolol can be used to control tachycardia and other sympathetic symptoms associated with hyperthyroidism.
Key considerations in the management of hyperthyroidism in acute illness include:
- Monitoring thyroid function closely but avoiding initiation of anti-thyroid treatment unless severe symptoms or thyroid storm occur
- Treating the underlying acute illness as the priority
- Using beta-blockers (e.g., propranolol 20-80 mg every 4-6 hours) to control tachycardia and other sympathetic symptoms if severe symptoms or thyroid storm occur
- Considering the use of propylthiouracil (PTU) 200-400 mg every 8 hours orally or via nasogastric tube in cases of severe hyperthyroidism or thyroid storm
Additional considerations include:
- Obtaining thyroid function tests (TSH, free T4, free T3) at presentation and monitoring every 24-48 hours
- Being aware that acute illness can cause transient thyroid function abnormalities (sick euthyroid syndrome) that typically resolve without specific thyroid treatment
- Continuing anti-thyroid treatment for the duration of the acute illness and reassessing thyroid function upon recovery if treatment is necessary, as supported by the discussion of beta-blocker treatment in patients with thyrotoxicosis or symptomatic hyperthyroidism 1.
From the FDA Drug Label
WARNING Severe liver injury and acute liver failure, in some cases fatal, have been reported in patients treated with propylthiouracil. Propylthiouracil should be reserved for patients who cannot tolerate methimazole and in whom radioactive iodine therapy or surgery are not appropriate treatments for the management of hyperthyroidism.
The FDA drug label does not answer the question.
From the Research
Management of Hyperthyroidism in Acute Illness
The management of hyperthyroidism in acute illness involves the use of beta blockers as adjuvant therapy to control symptoms such as nervousness, tremor, and tachycardia.
- Beta blockers, such as propranolol, are widely used to manage hyperthyroidism symptoms 2, 3.
- The use of beta-1 selective beta-blockers, such as atenolol and metoprolol, has been recommended over nonselective beta-blockers like propranolol in some guidelines 4.
- However, a study found that the choice between beta-1 selective beta-blockers and propranolol did not affect in-hospital mortality in patients with thyroid storm 4.
Beta Blocker Dosage and Administration
The dosage and administration of beta blockers in hyperthyroidism management vary depending on the specific medication and patient needs.
- Propranolol is typically administered orally at doses of 40 to 80 mg every 6 to 8 hours 2.
- In acute situations, intravenous administration of short-acting beta blockers may be more useful 2.
- A study found that a single dose of 80mg propranolol reduced heart rate substantially but resting energy expenditure (REE) diminished only marginally in hyperthyroid patients 5.
Effects of Beta Blockers on Thyroid Hormones
Beta blockers can affect thyroid hormone levels, although the clinical significance of these effects is not fully established.
- A study found that propranolol decreased serum T3 concentrations and increased the rT3/T3 molar ratio in some hyperthyroid patients 6.
- Another study found that long-term treatment with propranolol reduced REE, but the acute effect of propranolol on REE was minimal 5.
- Beta blockers may also have endocrinological effects on other hormone levels, such as gastrin, cyclic AMP, and catecholamines 3.