Amiodarone is an antiarrhythmic medication, i.e., it is used to treat irregular heartbeats. Doctors are, however, often hesitant in using it or other iodine-containing medications among patients with shellfish allergies because of a common misconception that shellfish allergy correlates to iodine allergy. However, here is a case report demonstrating that amiodarone has been safely used in treating 65-year-old Caucasian male with a shellfish allergy who developed atrial fibrillation and hypotension after coronary artery bypass and duodenal ulcer surgery. Oral amiodarone was administered to the patient without incident, and he was discharged on 200 mg twice daily with no signs of a drug allergy.

So if it's not due to iodine, what's the offending substance in shellfish that brings about allergic reactions?

Shellfish allergies are most likely the result of tropomyosin, an allergen in shrimp and lobster. Tropomyosins are a protein found in invertebrates, such as shellfish, and vertebrates, such as fish, and are needed for muscle contraction in these creatures. Tropomyosins are present in other foods as well, such as beef, pork, and chicken, but rarely cause reactions in these foods. In theory, any food that contains a protein could result in an allergic reaction. The possibility of a correlation between an allergy to shellfish and an iodine allergy is highly unlikely.

The third page of the case report clarifies the differences between food allergies, food hypersensitivity, food intolerance, and oral allergy syndrome. It also discusses the difference between IgE-mediated or non-IgE-mediated hypersensitivity reactions (I've read about this hundreds of times, but my eyes still glaze over when I read this immunology stuff, arrgh!).

Do you have shellfish or seafood allergies? I don't, but my 4-year old multiple food-allergic son does. :(