Levothyroxine and liothyronine and Pseudoephedrine interaction
Levothyroxine and liothyronine and Pseudoephedrine: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Levothyroxine and liothyronine (NP Thyroid 60) label · effective 2026-01-01
Larger doses may produce serious or even life-threatening manifestations of toxicity, particularly when given in association with sympathomimetic amines such as those used for their anorectic effects.
From the Pseudoephedrine (Pseudoephedrine hydrochloride) label · effective 2026-05-06
Ask a doctor before use if you have heart disease high blood pressure thyroid disease diabetes trouble urinating due to an enlarged prostate gland When using this product do not exceed recommended dosage Stop use and ask a doctor if nervousness, dizziness, or sleeplessness occur symptoms do not improve within 7 days or occur with a fever If pregnant or breast-feeding,…
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Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.