Levothyroxine and Timolol interaction
Levothyroxine and Timolol: 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 Timolol (Timolol Maleate) label · effective 2024-11-04
Patients suspected of developing thyrotoxicosis should be managed carefully to avoid abrupt withdrawal of beta-adrenergic blocking agents that might precipitate a thyroid storm.
From the Levothyroxine (Levothyroxine Sodium) label · effective 2024-07-10
Drug or Drug Class Effect Beta-adrenergic antagonists e.g., Propranolol > 160 mg/day) In patients treated with large doses of propranolol (> 160 mg/day), T 3 and T 4 levels change slightly, TSH levels remain normal, and patients are clinically euthyroid.
It should be noted that actions of particular beta-adrenergic antagonists may be impaired when the hypothyroid patient is converted to the euthyroid state.
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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.