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Things To Know About Morphine Allergy

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Allergic reaction to codeine and allergic reaction to hydrocodone Photo: Getty Images

It is standard now for doctors, dentists and other health care practitioners to ask patients about their allergy history. For most of us, knowing what we’re allergic to is something we carry around with us, often from childhood.

My mother, for example, was allergic to penicillin so from a young age I was drilled to tell doctors “I’m not sure, but my mother is allergic to penicillin,”on the off-chance that this allergy had been handed down.

The reason is obvious: allergies can run the gamut from being annoying and itchy to interfering with your every-day life and functioning, and can even become fatal.

So what happens if you’re in a situation where you’re in extreme pain and need something to get through the it while you, heal but are allergic to it? Oftentimes people are allergic to morphine, so what is its alternative, if any?

Morphine, a sedative, is very often used for the treatment of pain. While true morphine allergies are relatively rare, adverse responses to morphine are more common.

A “true” allergic reaction has to do with the immune system. If you have an immune system which does not respond well to morphine, alternate drugs, including a different class of opiates may be prescribed to handle the pain you’re experiencing.

Three different classes of opioids, which are commonly used in the treatment of pain are: phenanthrenes, phenylpiperidine, and phenylheptane. Morphine, codeine, as well as oxycodone, and hydrocodone all belong to the phenanthrenes class.

A patient may be prescribed a drug from another class of opiods, such as fentanyl, which is from the phenylpiperidine class, as a morphine alternative. Fortunately, if a patient suffers an adverse reaction to morphine or codeine, he or she will rarely exhibit the same symptoms from a drug in one of the other opioid classes.

If the allergy manifests itself as a skin rash, such as blisters or hives, you may be given a type of patch known as a diagnostic patch test. This will determine whether or not your rash is actually a result of taking morphine.

A morphine allergy symptom that can easily be overlooked is simple nasal congestion. Similar to other types of allergic sensitivities, in nasal congestion histamines are released by the immune system as it is exposed to the allergen, in this case, morphine. The result will be similar to other types of nasal congestion reactions -- watery eyes, runny nose and a similar experience as you might have with hay fever.

Bronchospasm, the constriction of the muscles of the airways of the lungs, makes breathing extremely difficult. This condition is something many physicians attempt to avoid, and because it can be brought on by morphine, some physicians will opt out of prescribing morphine altogether. (The Internet Journal of Asthma, Allergy and Immunology)

Anaphylaxis, a true immune system allergic response, affects one’s whole body. It is characterized by a very rapid onset of symptoms. These can include difficulty breathing, swallowing, or controlling one’s anxiety and confusion. It can also cause a slurring of speech, light-headedness, palpitations and fainting. Anaphylaxis can be life-threatening and requires immediate medical attention.


What Are The Symptoms of Morphine Allergy. March 30, 2011 by Charis Grey
Livestrong.com. Retrieved from the internet on November 7, 2011

Symptoms of Morphine Allergy. Retrieved from the internet on November 7, 2011.

Opioids: Allergy vs. Pseudoallergy. M. Saljoughian, PharmD, PhD
Department of Pharmacy, Alta Bates Summit Medical Center,
Berkeley, California. Retrieved from the internet on November 7, 2011.

Gary P. Zaloga MD, FCCM, FCCP et. al.Propofol-induced Bronchodilation In Patients With Status Asthmaticus. The Internet Journal of Asthma, Allergy and Immunology. 2001 Volume 1 Number 2. Retrieved from the internet on November 7, 2011.

Aimee Boyle is a regular contributor to EmpowHER

Reviewed November 11, 2011
by Michele Blacksberg RN
Edited by Malu Banuelos

Add a Comment5 Comments

EmpowHER Guest

When I was put on Morphine after surgery, hours later I started to complain of a horrible headache that was so bad it had me in tears. Nothing was helping until they weaned me off of the Morphine. Was this an allergic reaction and should I be sure to tell doctors I am allergic to Morphine?

October 30, 2016 - 2:40am
EmpowHER Guest

Will Benadryl stop an allergic reaction to morphine?

March 25, 2016 - 5:06pm
Guide (reply to Anonymous)

Hello Anonymous,

Good question.

True anaphylactic reactions to opioids are very rare. When patients say they are allergic to an opiod, it is much more likely that the patient has experienced GI upset or a pseudoallergy.
Flushing, itching, hives, and sweating, especially itching or flushing at the injection site only, suggests a pseudoallergy due to histamine release, a pharmacologic side effect of some opioids. Codeine, morphine, and meperidine are the opioids most commonly associated with pseudoallergy. Use of a more potent opioid is less likely to result in histamine release.

According to Emergency Physicians Monthly, "It would also seem that if the adverse reactions to opioids are due to histamine release that administering the opioids with an antihistamine such as Phenergan, Vistaril, or Benadryl would serve both to stop the “allergic” reaction and to enhance the effect of the pain medication."


March 28, 2016 - 9:38am
EmpowHER Guest

Can you tell me why my husband stop breathing 5 minutes from morphine

February 17, 2015 - 10:42am
Guide (reply to Anonymous)

Hello Anonymous,

Your husband stopped breathing for five minutes while receiving morphine because morphine has a direct effect on the respiratory centers of the brain stem. Decrease in respiration is a serious side effect of this drug.


February 17, 2015 - 10:49am
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We value and respect our HERWriters' experiences, but everyone is different. Many of our writers are speaking from personal experience, and what's worked for them may not work for you. Their articles are not a substitute for medical advice, although we hope you can gain knowledge from their insight.

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