From the Research
It is generally safe to give Norco (hydrocodone/acetaminophen) to a patient who is allergic to morphine, as a recent study found no cross-reactivity among opioid classes, resulting in 100% re-exposure tolerance rates 1. When considering the administration of Norco to a patient with a reported morphine allergy, it is essential to assess the nature of the previous reaction to morphine. Many patients who report morphine allergies may actually be experiencing side effects rather than true allergic reactions, as true opioid allergies are rare and most reactions are due to histamine release rather than IgE-mediated allergies 2, 3. Some key points to consider:
- Cross-reactivity between different opioids varies, and many patients can tolerate opioids from different classes without adverse reactions 1.
- If the patient had a severe allergic reaction to morphine (such as anaphylaxis), it would be prudent to start with a lower dose of Norco (such as 5/325 mg) and monitor closely for any adverse reactions.
- Always document the specific nature of the patient's previous reaction to morphine to better assess the risk of cross-reactivity.
- Consider consulting with an allergist before administration or exploring non-opioid pain management alternatives if the patient has had severe reactions to multiple opioids in the past. The most recent and highest quality study on this topic found no cross-reactivity among opioid classes, which supports the safety of administering Norco to patients with a reported morphine allergy 1.