Moderate
Amiodarone × Iopromide
Class III antiarrhythmics (Vaughan Williams)×X-ray contrast media. Watersoluble nephrotropic low-osmolar iodinated agents
Mechanism
Amiodarone contains 37% iodine in its structure. With iodine contrast (iopromide), total iodine load rises sharply, which can trigger amiodarone-induced thyrotoxicosis in predisposed patients (nodular goitre, autoimmune thyroiditis).
Symptoms
Palpitations, sweating, tremor, weight loss, anxiety, hyperthermia. Symptoms develop 1–3 months after contrast.
Management
Before elective contrast imaging on amiodarone, check TSH and T4. With normal thyroid function and nodular goitre, consider non-contrast alternatives (MRI without contrast). After imaging, check TSH at 1, 3, and 6 months. In thyrotoxicosis, stop amiodarone if feasible and start thiamazole plus prednisolone.