What is the proper dosage and administration of Armor thyroid (desiccated thyroid) for patients with hypothyroidism?

Dosage and Administration of Armour Thyroid for Hypothyroidism

Levothyroxine (LT4) is the preferred treatment for hypothyroidism, with Armour thyroid (desiccated thyroid) being a second-line option that should be used with caution due to potential inconsistencies in T3 content and associated risks.

Initial Dosing Guidelines

• For young, healthy adults without cardiac disease:

  • Start with a low dose of 15-30 mg daily
  • Gradually titrate upward every 4-6 weeks based on clinical response and laboratory values
  • Target dose is typically 60-120 mg daily, divided into 1-2 doses

• For elderly patients or those with cardiac disease:

  • Start with a lower dose of 15 mg daily
  • Increase by 15 mg increments every 6-8 weeks
  • More cautious titration is required due to increased risk of adverse cardiac effects 1

Monitoring and Dose Adjustment

• Check TSH and free T4 levels 6-8 weeks after initiating treatment
• Adjust dose in 15 mg increments to maintain TSH within reference range (0.4-4.0 mIU/L)
• After stabilization, monitor thyroid function every 6-12 months 2
• Monitor for signs of overtreatment: tachycardia, tremor, insomnia, heat intolerance

Special Considerations

Advantages of Armour Thyroid

• Contains both T4 and T3 in a fixed ratio (approximately 4.22:1)
• Some patients report better symptom relief compared to levothyroxine alone 3

Disadvantages and Risks

• Inconsistent T3 content may lead to variable hormone levels
• Higher T3 content than physiologic ratio (natural ratio is approximately 11:1) 4
• Increased risk of cardiovascular events due to potential for thyrotoxic effects 5
• Not recommended for patients with cardiac disease or elderly patients due to increased risk of arrhythmias and osteoporosis 1

Clinical Pearls

• Take on an empty stomach, at least 30-60 minutes before breakfast
• Avoid taking with calcium, iron supplements, or antacids which can reduce absorption
• Patients should be educated about signs of overtreatment requiring dose reduction
• Consider switching to levothyroxine in patients with cardiovascular risk factors

Common Pitfalls to Avoid

1. Self-administration without medical supervision - can lead to serious adverse effects including myocardial infarction 5

2. Rapid dose escalation - can precipitate cardiac events, especially in elderly or those with heart disease

3. Ignoring symptoms of thyrotoxicosis - tachycardia, tremor, and heat intolerance warrant immediate dose reduction

4. Using for weight loss - inappropriate use as a weight loss supplement is dangerous and should be discouraged 5

5. Failure to recognize drug interactions - certain medications can affect thyroid hormone metabolism

When to Consider Endocrinology Referral

• Patients with persistent symptoms despite normalized TSH
• Complex cases with multiple endocrine disorders
• Difficulty achieving stable thyroid function
• Patients with cardiac disease requiring thyroid hormone replacement 2

While some patients may report better symptom control with desiccated thyroid preparations like Armour Thyroid, current guidelines from major endocrine societies recommend levothyroxine as first-line therapy due to more consistent hormone content and better safety profile 1, 6.