Doctors don’t know why opioids make their patients itch; however, researchers have identified several factors that could explain why the drugs cause itching.
If you react poorly to one type of opioid, switching to a different version may help. Medications and at-home care could help too.
Why Do Opioids Make You Itch?
Researchers believe opioids cause itching by activating the immune system, altering serotonin levels or triggering key brain centers associated with pain. If your doses make you itch, you’re not necessarily allergic to them.
Opioids are prescription painkillers. They’re similar to illicit opiates (like heroin), but they’re made in controlled environments by chemists. Opioids work by latching to opioid receptors in the brain. Latching triggers euphoria, making pain signals easier to ignore.
Between 2% and 10% of people who use opioids develop itching. The risk is higher when people get their drugs via injection rather than swallowing pills.
Doctors consider itching a side effect, not a complication. If your drugs spark mild redness and itching, you’re not experiencing an allergic reaction. Instead, your drug is working on well-known pathways that could lead to itching.
Opioids could make you itch due to the following issues:
- Histamines: Histamine is a neurotransmitter that your body could release in response to opioids.
- Local reactions: Opioid receptors near your skin and around your hair could cause inflammation and itching when the drugs latch.
- Brain changes: The medullary dorsal horn in the brain processes pain signals. Opioids can activate this brain center, causing itching.
- Serotonin: Opioids can alter the serotonin system, changing heart rates and nervous system responses. Sometimes, that causes itching.
- Pain: Your brain processes pain and itching similarly. Sometimes, a pain signal is interpreted as itching instead.
Itching is uncomfortable, but it’s rarely life-threatening. Most people with opioid-induced itching develop red, puffy, itchy skin and no other symptoms. With the proper treatment, they can be much more comfortable.
Which Opioids Cause Itching?
Most opioids can cause itching, including morphine, fentanyl, codeine, oxycodone (OxyContin) and hydrocodone (Vicodin). All opioids latch to receptors in the brain and body. The latching and resultant chemical changes can make you itch.
Researchers know that some medications cause more severe itching than others. Stronger drugs (like fentanyl) tend to cause larger itch reactions than their weaker counterparts (like morphine).
If you are struggling to discontinue opioid use, medications like Suboxone can help. Suboxone is a partial opioid itself. Like other opioids, it can also sometimes cause itching, but the itching may be less severe than someone taking full opioid agonists.
How Do You Stop the Itching From Opioids?
If your opioids make you itch, over-the-counter antihistamines may help. Switching to a different type of opioid may be effective too. Your doctor can help you decide which approach is best.
Researchers say some people get relief from antihistamines with diphenhydramine, like Benadryl, Sudafed PE and Unisom. You can get these medications without a prescription. But some people need stronger, prescription-grade antihistamines with promethazine.
Using an antihistamine for an opioid itch comes with some risks. Antihistamines can be sedating, and opioids cause the same problem. Putting them together can lead to severe sedation. Never combine them without asking your doctor first.
If your itching is severe, your doctor may try a different drug in the same class. A simple swap like this could be enough to make the discomfort fade.
Always contact your doctor if your itching is severe, interferes with your breathing or impacts your opioid treatment.
Alternate Treatment Options for People on Suboxone With Itching
If you’re using MAT therapies like buprenorphine and itching begins, your doctor has several options to help you, such as these:
- Investigating: Other substances, medications and medical conditions can cause itching. Your doctor can help you spot them.
- Switching: If buprenorphine causes itching, opting for methadone might be helpful.
- Alternating: Splitting your dose into several batches may help instead of taking them all at once.
- Waiting: Sometimes, the itch goes away as your body grows accustomed to the medication.
Itching can interfere with your sleep, make concentration difficult and just make life harder. It’s difficult to focus on your recovery when you’re dealing with an itch.
But never quit taking your medications without talking to your doctor first. Your recovery is important, and your doctor is a critical part of your team. Explain your itching and ask for help before you make any decisions.
Frequently Asked Questions
We’ve compiled some of the most frequently asked questions about opioid-induced itching.
Some people experience an itch the entire time they take opioids. Others notice their symptoms fade within a week or two.
Severity is the main difference between allergies and side effects. A true opioid allergy causes severe symptoms like skin lesions, swollen eyes, low blood pressure and difficulty breathing. Mild itching is a side effect, not a symptom of an opioid allergy.
Opioids can cause side effects like constipation, sedation and nausea. Continued use can lead to dependence (needing to use more to feel normal) or opioid use disorder (an inability to quit when you want to).
Reviewed By Peter Manza, PhD
Peter Manza, PhD received his BA in Psychology and Biology from the University of Rochester and his PhD in Integrative Neuroscience at Stony Brook University. He is currently working as a research scientist in Washington, DC. His research focuses on the role ... Read More
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