Propranolol Dosing for Thyroiditis
For symptomatic management of thyroiditis, start propranolol at 40-80 mg daily divided into 2-3 doses, with a typical maintenance range of 80-160 mg daily based on clinical response. 1, 2
Initial Dosing Strategy
- Begin with 40-80 mg daily in divided doses (2-3 times per day) for optimal symptomatic control of autonomic hyperactivity including tremor, palpitations, tachycardia, and sweating 1, 2
- The total daily dose range for thyrotoxicosis is 40-160 mg daily, with most patients requiring 80-160 mg for adequate symptom control 1, 2
- Doses of 40 mg every 6-8 hours (160 mg/day total) have been historically effective, though some patients may need up to 320 mg/day in severe cases 3, 4
Dose Titration Based on Response
- Aim for >25% reduction in resting heart rate as a marker of adequate beta-blockade 5
- If symptoms persist on standard dosing (160 mg/day), the dose can be increased, particularly in severely thyrotoxic patients who may require higher doses 5
- Adjust dosing based on heart rate and blood pressure monitoring at each visit 1
Critical Pre-Treatment Assessment
Before initiating propranolol, screen for absolute contraindications:
- Second or third-degree heart block 1, 2
- Decompensated heart failure 1, 2
- Asthma or obstructive airway disease 1, 2, 3
- Cardiogenic shock or severe hypotension 2
Perform baseline evaluation including:
- Heart rate and blood pressure measurement 1, 2
- Cardiovascular examination with auscultation 2
- Screen for diabetes (propranolol masks hypoglycemia symptoms) 1, 2
- Review concurrent medications affecting cardiac conduction 2
Administration and Monitoring
- Administer with food to reduce hypoglycemia risk 1, 2
- Hold doses during periods of diminished oral intake or vomiting 2
- Monitor thyroid function (TSH, FT4) every 2-3 weeks to detect transition to hypothyroidism, which commonly follows the thyrotoxic phase 2
- Watch for adverse effects including bradycardia, hypotension, fatigue, dizziness, and cold extremities 2
Duration and Discontinuation
- Beta-blocker therapy is temporary and symptom-driven, typically needed only during the thyrotoxic phase (usually weeks in subacute thyroiditis) 2
- Never abruptly discontinue propranolol after chronic use—taper gradually over several weeks to prevent rebound tachycardia and hypertension 1, 2
Important Clinical Caveats
- Propranolol provides symptomatic relief only and does not affect the underlying thyroid pathology or disease course 2
- In severely thyrotoxic patients, conventional doses (160 mg/day) may be insufficient, and supplemental dosing may be required 5
- Propranolol alone is not recommended as primary therapy for long-term management of hyperthyroidism—it should be combined with definitive treatment (antithyroid drugs, radioiodine, or surgery) except in self-limited conditions like subacute thyroiditis 2, 6
- Avoid combining with non-dihydropyridine calcium channel blockers (diltiazem, verapamil) due to increased risk of bradycardia and heart block 2