Propranolol Dosing for Thyrotoxicosis
For adults with thyrotoxicosis, propranolol should be administered at a dose of 40-160 mg daily in divided doses for symptomatic relief. 1
Dosing Guidelines
- Initial starting dose for thyrotoxicosis should be 40-80 mg daily, divided into 2-3 doses for optimal symptomatic control 1
- Maintenance dose typically ranges from 80-160 mg daily based on clinical response and symptom control 1, 2
- Higher doses (up to 320 mg/day) may be required in severely thyrotoxic patients to achieve adequate beta-blockade 3
- A greater than 25% reduction in sitting pulse rate indicates adequate beta-blockade and should guide dosing adjustments 3
- Dosing should be adjusted based on plasma propranolol levels, which correlate with reduction in heart rate and clinical improvement 4
Monitoring Parameters
- Heart rate and blood pressure should be monitored before initiating treatment and at follow-up visits 1
- Target a reduction in resting heart rate to normal range for optimal symptom control 4
- Plasma propranolol levels may be lower in thyrotoxic patients due to increased clearance (42% lower compared to euthyroid state) 5
- Free fraction of propranolol is higher in thyrotoxic patients (14.2% vs 11.4% in euthyroid state), requiring dose adjustments 5
Special Considerations
- Propranolol alone provides symptomatic relief but does not treat the underlying thyroid dysfunction 6, 2
- For perioperative management of thyroidectomy, propranolol at an average dose of 160 mg/day (range 40-320 mg/day) effectively controls symptoms 2
- Severely thyrotoxic patients may require higher doses and more frequent monitoring 3
- Propranolol should be administered with food to reduce the risk of hypoglycemia 7
Contraindications and Precautions
- Propranolol is contraindicated in patients with asthma, obstructive airway disease, decompensated heart failure, and second or third-degree heart block 7
- Use with caution in patients with diabetes as propranolol may mask symptoms of hypoglycemia 7
- Abrupt discontinuation should be avoided to prevent rebound tachycardia 7
Clinical Pearls
- Propranolol effectively neutralizes symptoms of autonomic hyperactivity including sweating, tremor, fever, vasodilation, and tachycardia 2
- Weight loss may continue despite propranolol therapy, with the degree of continued weight loss inversely related to plasma propranolol concentration 4
- Conventional dosing of 160 mg/day may be insufficient for severely thyrotoxic patients 3
- Propranolol can reduce serum T3 levels but has minimal effect on serum T4 4