935 - Cross-reactivity between contrast iodine and Ketorolac

A 41-year-old male with past medical history of iodine-induced anaphylaxis, was given intramuscular ketorolac for his lumbar back pain during a routine electrodiagnostic appointment. Within one minute of receiving the injection, the patient experienced a metallic taste followed by dry mouth symptoms, similar to his prior severe iodine allergic reaction. The patient was immediately transported to the emergency room and given intravenous Benadryl with instant resolution of his worsening symptoms.

Discussions:

Both the immediate onset and near identical symptoms to his prior iodine allergic reaction helped identify that the patient had developed an allergic reaction to ketorolac. After a thorough literature review and in-depth discussion with the pharmacy department, it was found that there is evidence of cross-reactivity between iodine and NSAIDs.  Notably, cross-reactivity specifically between contrast iodine and ketorolac is extremely rare in patients who had otherwise tolerated other NSAIDs in the past.

Conclusions:

This case highlights the importance of early identification of red flag symptoms even when following routine pain management protocols. The presence of early symptoms identical to prior severe allergic reactions such as metallic taste and mouth dryness should not be overlooked. These symptoms may serve as early warning signs of a repeat anaphylactic episode. Intravenous Benadryl administration is a first-line treatment in anaphylaxis and should be given as soon as anaphylaxis is suspected. It is thus imperative to review prior severe allergic reaction symptoms and cross-reactivity before administrating new medications.