Levothyroxine and Nortriptyline interaction

Levothyroxine and Nortriptyline: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.

Moderate

Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.

What the FDA labels say

From the Levothyroxine (Levothyroxine Sodium) label · effective 2024-07-10

Moderate

Antidepressant Therapy Concurrent use of tricyclic (e.g., amitriptyline) or tetracyclic (e.g., maprotiline) antidepressants and levothyroxine may increase the therapeutic and toxic effects of both drugs, possibly due to increased receptor sensitivity to catecholamines.

Drug interactionsby drug classView label on DailyMed
Minor

Levothyroxine may accelerate the onset of action of tricyclics.

Drug interactionsby drug classView label on DailyMed

From the Nortriptyline (PAMELOR) label · effective 2024-12-04

Minor

Great care is required if Pamelor is given to hyperthyroid patients or to those receiving thyroid medication, since cardiac arrhythmias may develop.

Warningsby drug classView label on DailyMed

Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.

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Not 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.