Opioid-allergy alerts often create a conundrum...since most reactions are documented incorrectly or incompletely.
And less than 2% of opioid reactions are a true allergy.
Use any opioid intolerance as an opportunity to ensure NON-opioid alternatives are optimized.
Then follow a practical approach to handle opioid-allergy alerts.
Document in the EHR the specific med...the reaction...and if the patient has tolerated other opioids since the reaction.
Filter out NONallergic reactions. We know that nausea, GI upset, dizziness, and other common adverse effects aren’t allergies. See if your EHR will let you label these as “intolerances.”
Expect flushing, itching, and hives to often be “pseudoallergy”...caused by direct histamine release due to opioids.
Be aware, pseudoallergy isn’t immune-mediated and doesn’t require prior exposure to an opioid.
Be familiar with key culprits...codeine, morphine, meperidine.
If needed, consider switching to an opioid that may cause less histamine release, such as hydrocodone or oxycodone.
If the opioid can’t be changed, try a lower dose...or pretreating with a second-generation antihistamine (cetirizine, etc) and possibly an H2-blocker (famotidine, etc).
Hone in on true allergies. Be alert for angioedema, bronchospasm, severe hypotension, severe skin reactions, etc.
In these cases, suggest an opioid from a different structural class...plus close monitoring.
Think of four major structural classes.
Morphine-like opioids include codeine, hydrocodone, hydromorphone, and oxycodone.
Fentanyl and meperidine are structurally similar to each other...so are tramadol and tapentadol (Nucynta).
Methadone is structurally unique.
For example, consider IV hydromorphone as a potential alternative for a patient with a true allergy to fentanyl.
See our resource, Opioid Allergy, for more details about cross-reactivity...including an algorithm to help guide treatment options.
- Powell MZ, Mueller SW, Reynolds PM. Assessment of Opioid Cross-reactivity and Provider Perceptions in Hospitalized Patients With Reported Opioid Allergies. Ann Pharmacother. 2019;53(11):1117-1123.
- Kalangara J, Potru S, Kuruvilla M. Clinical Manifestations and Diagnostic Evaluation of Opioid Allergy Labels - A Review. J Pain Palliat Care Pharmacother. 2019 Sep-Dec;33(3-4):131-140.
- Zhang B, Li Q, Shi C, Zhang X. Drug-Induced Pseudoallergy: A Review of the Causes and Mechanisms. Pharmacology. 2018;101(1-2):104-110.
- Joint Task Force on Practice Parameters; American Academy of Allergy, Asthma and Immunology; American College of Allergy, Asthma and Immunology; Joint Council of Allergy, Asthma and Immunology. Drug allergy: an updated practice parameter. Ann Allergy Asthma Immunol. 2010 Oct;105(4):259-273.