Drug reference
liothyronine
thyroid hormone · thyroid hormone replacement
thyroid hormonethyroid hormone replacement
CDSCO approved
EXCRETION
—
not curated
INTERACTIONS
—
none in our sources
PREGNANCY
A
FDA category + note
Mechanism
Identical to endogenous T3. Has a much higher affinity for the nuclear thyroid hormone receptor (TR) compared with T4 and is much more potent biologically on a molar basis.
Indications
thyroid hormone replacement when rapid onset of action is desired (e.g., myxedema coma)thyroid hormone replacement when rapid termination of action is desired (e.g., preparing thyroid cancer patients for radioiodine therapy)Myxoedema coma
Dosing
- Adult
- To achieve steady serum T3 levels, multiple daily doses are required. The required daily dose is about one-third that of levothyroxine. Myxedema coma: 10 μg intravenously followed by 2.5–10 μg every 8 h.
Pharmacokinetics
Peak effect
Serum levels peak 2 to 4 h following oral ingestion.
Half-life
~18–24 h
Bioavailability
Nearly 100% absorption.
Protein binding
Only 0.2–0.5% of T3 is in the free form, less tightly bound than T4.
Side effects
Common
transient elevations of serum T3 concentrations above the normal range (with multiple daily doses)cardiac arrhythmiasangina
Pregnancy & lactation
Pregnancy
A
Related guidelines
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Sources: KD Tripathi 7e, Goodman & Gilman 14e·Verified: 2026-05-10 · House clinical team