Codeine Allergy Reactions, Symptoms & Alternatives
Having a codeine allergy is a problem some people face, which makes them unable to take this prescription opioid for pain or to treat a cough. The following provides an overview of what codeine is, and also what to know about a codeine allergy reaction, symptoms, and alternative options that may be available.

When someone takes codeine, and it reaches their brain, it’s converted to morphine. It then attaches to opioid receptors, and that’s how it relieves sensations of pain and suppresses the cough reflex in the brain. Codeine also slows the activity of the central nervous system, which is why it’s important for patients to take it exactly as prescribed. Otherwise, an overdose is possible.
When someone takes codeine, it does increase their pain tolerance, but they still feel the pain, which is why it’s often combined with other pain relievers like acetaminophen. This makes it more effective as a pain reliever.
Codeine also has sedative effects, so it can cause drowsiness.
While less so than other opioid narcotics, codeine can be habit-forming, and it’s also possible for people to have a physical dependence on it after taking it for a longer period of time, meaning they will experience symptoms of withdrawal if they suddenly stop.
People may also experience a codeine allergy. It’s not uncommon for people to experience allergic reactions to various medications, and it can be a hereditary trait. This means that if your parents or grandparents have a codeine allergy, you may be at a higher risk of this as well.
However, while a codeine allergy is certainly possible, there are also many people who think they have a codeine allergy when they’re really only experiencing the side effects of the drug itself. For example, itchiness is a common codeine side effect, and it’s also a side effect of other opioid drugs as well. It’s not indicative of a codeine allergy. Nor are other symptoms like blurred vision or constipation. These are all just normal symptoms of using codeine.
For example, if someone takes codeine and they experience itching, sweating, or flushing, it could be a pseudoallergy. This happens because when you take opioids, it can trigger a histamine response, which is what happens when you have an allergic reaction as well. Codeine is one of the opioids most commonly associated with pseudoallergies.
The reason people tend to believe they’re experiencing a codeine allergy reaction with this opioid more than others is because it’s one of the less potent ones, so it is more likely to trigger a histamine release.
There are two different scenarios to consider when you’re looking for a codeine allergy alternative.
The first is what would happen if you have a pseudoallergic reaction to codeine. In this case, a doctor would most likely prescribe you a stronger opioid, because stronger opioids tend to have less noticeable histamine reactions.
If you are truly allergic to codeine, you will have to be given a pain reliever from a different class of medications, because you are likely allergic to all opioid medicines.
To sum up, is a codeine allergy possible? It is possible to be allergic to codeine, but it’s rare. More often than not, the symptoms people experience that they think are related to a codeine allergy are just symptoms of the drug that are normal and are caused by their body’s histamine response.
Some of the symptoms of codeine that could be related to an allergy or a normal response include feeling dizzy, having hives or experiencing itchiness. Regardless of whether you think these symptoms are related to a codeine allergy or not, you should contact your physician if you experience them after taking codeine.
If you are truly allergic to codeine, your doctor will have to prescribe you a drug from a different class outside of opioids.
Medical Disclaimer: The Recovery Village aims to improve the quality of life for people struggling with a substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare provider.
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