What type allergic reaction does codeine have?

Codeine can cause allergic reactions that typically fall under Type I hypersensitivity reactions, which are mediated by IgE antibodies. Symptoms may include hives, swelling, difficulty breathing, and anaphylaxis in severe cases. Additionally, some individuals may experience cross-reactivity with other opioids due to similar structures. It's important for anyone with a known allergy to codeine to avoid its use and inform healthcare providers of their allergy.