Most of us have probably known a person with a food allergy. There are plenty of people out there who are allergic to anything related to nuts, strawberries, corn, eggs, shellfish, wheat, and just about everything else you can think of. Some people are even allergic to coffee. But what about drugs and alcohol? Is it possible to be allergic to heroin or whiskey? While it’s not terribly common, it is possible. Most people who believe that they are allergic to a controlled substance are using some form of opioid. There are no exact statistics available, mostly because the frequency of false positive results make it difficult to tell if it was the drug use or some other factor that caused the allergic reaction.

Sometimes people claim that they have drug allergies, but in truth they are just sensitive to the substance. A true allergy results when a person’s immune system reacts abnormally to a substance that is harmless to most people. A drug intolerance, on the other hand, doesn’t involve an immune reaction. For example, as many as nine out of ten people who say that they are allergic to an opioid have only experienced a side effect that mimics allergic reactions. Codeine, morphine, and meperidine – which are all narcotics used to treat moderate to severe pain – are the main opioids that cause these allergy-like reactions, called pseudoallergies.

Pseudoallergies are caused by endogenous histamine release from the mast cells. Histamine is an organic compound released by cells that helps rid the body of allergens. Sometimes histamine can overreact and cause you to have allergy symptoms, for example, sneezing or having watery eyes. Endogenous histamine is histamine that is produced naturally in the body, rather than ingested. Mast cells are white blood cells that contain granules – think of them like a little storage sac – that are released when you’re exposed to an allergen. Symptoms of pseudoallergies include flushing, itching, sneezing, hives, sweating, worsened asthma, and low blood pressure.

As an interesting side note, people who are truly allergic to codeine and morphine will also be allergic to hydrocodone, oxycodone, buprenorphine, and heroin. These drugs are all structurally similar to each other.


Similarly, it can be difficult to tell whether you’re allergic to alcohol or just intolerant. Typically, people aren’t allergic to the alcohol itself but to yeast or additives. For example, people who are gluten intolerant will have bad reactions to drinking beer that is made with malted barley, which contains gluten. Wine, particularly red wine, contains histamine, which causes many people to have reactions such as sneezing, flushed skin, headache, diarrhea, itchy skin, and shortness of breath. Alcohol intolerance has similar symptoms, but it is caused by a genetic mutation that prevents the body from being able to break down alcohol properly. If you have an alcohol intolerance, there’s no treatment other than to not drink.

If you or a loved one need help with quitting drugs or alcohol, consider Asana Recovery. We offer medical detox, along with both residential and outpatient programs, and you’ll be supervised by a highly trained staff of medical professionals, counselors, and therapists. Call us any time at (949) 438-4504 to get started.