- PO (Adults ): Hypothyroidism: 1.6 mcg/kg once daily; may ↑ by 12.5–25 mcg/day every 4–6 wk until patient clinically euthyroid based on signs/symptoms and TSH levels.
- PO Geriatric Patients and Patients with Cardiac Disease): 12.5–25 mcg once daily; may ↑ by 12.5–25 mcg/day every 6–8 wk until patient clinically euthyroid based on signs/symptoms and TSH levels.
- PO (Children >12 yr): 2–3 mcg/kg/day (≥150 mcg/day).
- PO (Children 6–12 yr): 4–5 mcg/kg/day (100–125 mcg/day).
- PO (Children 1–5 yr): 5–6 mcg/kg/day (75–100 mcg/day).
- PO (Children 6–12 mo): 6–8 mcg/kg/day (50–75 mcg/day).
- PO (Infants 3–6 mo): 8–10 mcg/kg/day (25–50 mcg/day).
- PO (Infants 0–3 mo or Infants at Risk for Cardiac Failure): 10–15 mcg/kg/day or 25 mcg/day; may ↑ after 4–6 wk to 50 mcg.
- IM IV (Adults ): Hypothyroidism: 50–100 mcg/day as a single dose. Myxedema coma/stupor: 300–500 mcg IV; additional 100–300 mcg may be given on 2nd day, followed by daily administration of smaller doses.
- IM IV (Children ): Hypothyroidism: 50–80% of the oral dose.
