What medications are used to treat thyroid storm?

Medications for Thyroid Storm Management

The standard treatment for thyroid storm requires a multi-drug approach including propylthiouracil or methimazole, potassium iodide, beta-blockers, corticosteroids, and supportive care. 1

First-Line Medications for Thyroid Storm

1. Thionamides (Anti-thyroid Drugs)

• Propylthiouracil (PTU) or Methimazole
  • Both inhibit new thyroid hormone synthesis
  • PTU has the additional benefit of inhibiting peripheral conversion of T4 to T3 2
  • Recent evidence shows no significant difference in mortality or adverse events between PTU and methimazole for thyroid storm treatment 3
  • Dosing:
    • PTU: Higher doses (typically 200-400 mg every 4-6 hours)
    • Methimazole: 20-25 mg every 4-6 hours

2. Beta-Blockers

• Propranolol is preferred due to its additional benefit of blocking peripheral T4 to T3 conversion 4
  • Dosing: 60-80 mg orally every 4-6 hours or 1-3 mg IV slowly
  • Caution: May mask signs of hypoglycemia and can exacerbate heart failure
• For patients with severe bronchospasm or heart failure where non-selective beta-blockers are contraindicated, selective beta-1 antagonists are preferred 5
• IV beta-blockers may be necessary in severe cases with significant tachycardia

3. Iodine Preparations (administered 1 hour AFTER thionamides)

• Saturated solution of potassium iodide (SSKI) or Lugol's solution
  • Blocks release of preformed thyroid hormone
  • Dosing: SSKI 5 drops every 6 hours or Lugol's solution 10 drops every 8 hours
• Alternative: Lithium carbonate if iodine allergies present

4. Corticosteroids

• Dexamethasone (preferred) or hydrocortisone
  • Inhibits peripheral conversion of T4 to T3
  • Treats potential relative adrenal insufficiency
  • Dosing: Dexamethasone 2-4 mg IV every 6 hours

5. Bile Acid Sequestrants

• Cholestyramine
  • Binds thyroid hormones in intestine and prevents enterohepatic recirculation
  • Particularly useful in severe cases

Treatment Algorithm

1. Immediate stabilization:

   • Oxygen, IV fluids, cooling measures for hyperthermia
   • Treat precipitating factors (infection, trauma, surgery, medication non-compliance)

2. Medication administration sequence:

   • Start beta-blocker for rate control
   • Administer thionamide (PTU or methimazole)
   • Wait 1 hour, then administer iodine preparation
   • Add corticosteroid
   • Consider cholestyramine for severe cases

3. Monitoring:

   • Continuous cardiac monitoring
   • Regular vital signs
   • Thyroid function tests
   • Assess for signs of improvement (decreased heart rate, temperature normalization)

Special Considerations

• Pregnancy: PTU is preferred over methimazole in the first trimester due to lower risk of birth defects 1
• Heart Failure: Use selective beta-1 blockers with caution; consider diltiazem or verapamil if beta-blockers contraindicated 1
• Bronchospasm: Avoid non-selective beta-blockers; consider diltiazem or verapamil 1

Common Pitfalls to Avoid

1. Administering iodine before thionamides - This can worsen thyrotoxicosis by providing substrate for hormone production
2. Delaying treatment - Do not wait for laboratory confirmation to initiate therapy 1, 6
3. Using non-selective beta-blockers in patients with severe heart failure or bronchospasm
4. Overlooking precipitating factors - Always identify and treat the underlying trigger
5. Inadequate monitoring - Thyroid storm requires intensive monitoring and often ICU-level care

Thyroid storm is a medical emergency with high mortality if not treated promptly and aggressively. The cornerstone of treatment involves inhibiting new hormone synthesis, blocking hormone release, preventing peripheral conversion of T4 to T3, and providing supportive care while addressing the precipitating cause.