Dulaglutide and Levothyroxine and liothyronine interaction
Dulaglutide and Levothyroxine and liothyronine: 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 Dulaglutide (Trulicity) label · effective 2026-06-16
WARNING: RISK OF THYROID C-CELL TUMORS In male and female rats, dulaglutide causes a dose-related and treatment-duration-dependent increase in the incidence of thyroid C-cell tumors (adenomas and carcinomas) after lifetime exposure.
It is unknown whether TRULICITY causes thyroid C-cell tumors, including medullary thyroid carcinoma (MTC), in humans as human relevance of dulaglutide-induced rodent thyroid C-cell tumors has not been determined [see Warnings and Precautions ( 5.1 ), and Nonclinical Toxicology ( 13.1 )] .
Counsel patients regarding the potential risk of MTC with use of TRULICITY and inform them of symptoms of thyroid tumors (e.g., mass in the neck, dysphagia, dyspnea, persistent hoarseness).
Routine monitoring of serum calcitonin or using thyroid ultrasound is of uncertain value for early detection of MTC in patients treated with TRULICITY [see Contraindications ( 4 ) and Warnings and Precautions ( 5.1 )] .
WARNING: RISK OF THYROID C-CELL TUMORS See full prescribing information for complete boxed warning.
From the Levothyroxine and liothyronine (NP Thyroid 60) label · effective 2026-01-01
Insulin or Oral Hypoglycemics — Initiating thyroid replacement therapy may cause increases in insulin or oral hypoglycemic requirements.
Patients receiving insulin or oral hypoglycemics should be closely watched during initiation of thyroid replacement therapy.
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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.