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Opioids are types of medicine used to relieve moderate to severe pain. They are also called opiates or narcotics and are a type of analgesic (painkilling) medicine. Opioids work in the brain and other parts of the body by attaching to pain receptors to block the feeling of pain. Some people with cancer need opioids for cancer-related pain.
Here are some of the common opioids used in cancer care. Brand names are in parentheses.
Opioids that are called extended release (ER), long-acting (LA), controlled release (CR), and sustained release (SR) are all long-acting forms. This means they release a little bit of the medicine over a longer period. They are often taken once or twice a day to treat chronic pain. A low dose of opioids might be prescribed first and then changes can be made based on how you’re feeling.
Immediate release (IR) opioids take effect more quickly over a shorter period (short-acting forms). These opioids are used to treat acute pain and breakthrough pain. They might be taken several times a day as needed.
There are pros and cons to long-acting and short-acting opioids.
At times, short-acting opioid might be used with a long-acting opioid to give steady relief.
Sometimes, the same opioid is used to treat both chronic and breakthrough pain. Morphine sulfate immediate release (MSIR) is a short-acting form of morphine. Morphine sulfate-controlled release (MS Contin) is a long-acting form of morphine. Someone might be prescribed both MSIR and MS Contin to get better pain control. It is important to know which you are taking and how you should take it.
Some opioids are combined with non-opioids in one medicine for better pain relief. Your doctor will review any combination of medicine for interactions and possible serious side effects.
See Non-opioids and Other Medicines to Treat Cancer Pain for more on acetaminophen and NSAIDs (nonsteroidal anti-inflammatory drugs) like aspirin and ibuprofen.
Oxycodone pills might also contain aspirin, acetaminophen, or ibuprofen. For instance:
Hydrocodone may be combined with acetaminophen or ibuprofen. For instance:
It may take a few changes to find what works best for you. Do not change how much or how often you take pain medicine without talking to your cancer care team first. If changing the dose or frequency doesn’t work, they may prescribe a different medicine or add a new one to what you’re already taking. Talk to your cancer care team if your medicines aren’t relieving your pain.
Learn more about developing a pain control plan with your cancer care team.
Opioids can be taken safely to get pain relief. Opioids can affect each person differently and should be used carefully for people of different ages. Some opioids cannot be given to older adults, young children, or certain people being treated for other medical conditions.
Opioids should be taken as prescribed by your cancer care team and should be used very carefully for several reasons:
Your cancer care team may prescribe opioids for increasing or severe pain and will talk to you about how to safely take opioids. Talk to your cancer care team to get answers to your questions or concerns.
If you are taking opioids, here are some important tips:
Your cancer care team might ask you questions to make sure it is safe for you to take opioids at home before prescribing them. They might ask who you live with, if anyone there has a history of addiction, if children are in the home, or how your medicines are stored.
Some things that can increase a person’s risk of opioid overdose include:
Taking too many opioids can slow or even stop a person’s breathing. Other signs of opioid overdose include:
Naloxone (Narcan) and Nalmefene are drugs that can be given to reverse the effects of opioids in case of an overdose. They both can be given as an injection or a nasal spray. Nalmefene nasal spray is only available with a prescription, but Narcan nasal spray can be bought over the counter without a prescription.
If you are taking opioids, your cancer care team might suggest that you keep one of these drugs where you can get to it quickly . Also make sure anyone you live with knows where it is and how to use it. This is even more important if you are taking a high dose of opioids or are at a higher risk of overdose. Ask your cancer care team to talk you through how to use it.
Over time, some people might need more of their pain medicine to get relief. They may have had a lower dose that used to work but now does not. This may be because the pain has increased, or they have developed a drug tolerance (your body gets used to the amount of opioid you’re taking, and it no longer relieves pain the way it did). Many people don’t develop a tolerance to opioids. But if you do, small increases in the dose or a change in the kind of medicine might help relieve the pain.
You should not suddenly stop taking opioids. People who need or want to stop taking opioids are usually tapered off (weaned off) the medicine slowly so that their bodies have time to adjust. It is normal for people's bodies to become dependent on opioids, so it takes time to adjust to not having them.
If you suddenly stop taking opioids and develop a flu-like illness, excessive sweating, diarrhea, or any other unusual reaction, tell your cancer care team. These symptoms can be treated and tend to go away in a few days or weeks. Check with your doctor about the best way to taper off your pain medicines and minimize these side effects.
A person with an addiction seeks to take opioids repeatedly to feel good. The craving for opioids can be so strong that it causes problems at work, with family, and daily activities. Someone with an addiction may have withdrawal symptoms if they cannot get the opioids their brain is used to having.
Symptoms of withdrawal are:
It’s important to know that not everyone who uses opioids will become addicted or misuse them. Opioids can be safely taken when used responsibly and as prescribed.
It is normal to have side effects when taking opioids, but everyone might not have side effects. The most common side effects are:
Some people might also have:
Many side effects from opioid pain medicine can be managed. Some of them such as nausea, itching, or drowsiness, might go away after a few days as your body adjusts to the medicine. If you're having any side effects, let your cancer care team know and ask for help managing them.
You might find that you feel sleepy when you first start taking opioids. If pain has kept you from sleeping, you may sleep more for a few days after starting opioids while you “catch up” on your sleep.
You also will get less sleepy as your body gets used to the medicine. Call your cancer care team if you still feel too sleepy for your normal activities after you’ve been taking the medicine for a week.
But if you continue to have drowsiness, or it gets worse and it becomes more of a problem, ask your cancer care team:
Sometimes it may be unsafe for you to drive a car, or even to walk up and down stairs alone. Don’t do anything that requires you to be alert until you know how the medicine affects you.
Opioids cause constipation in most people, but it can often be prevented or controlled. Opioids slow the movement of stool through the bowels, which allows more time for water to be absorbed by the body. This makes the stool harder.
When you start taking opioids, your doctor might suggest taking a laxative, stool softener, or other treatment to help keep your stool soft and your bowels moving. See Constipation for more information.
Nausea and vomiting caused by opioids usually go away after a few days of taking the medicine. See Nausea and vomiting for more information.
Some people think they’re allergic to the opioid if they have nausea after they take one or more doses. Nausea and vomiting alone don't usually mean you're having an allergic reaction.
But if you have a rash or itching along with nausea and vomiting, you might be having an allergic reaction. If this happens, stop taking the medicine and call your doctor right away. If you have swelling in your throat, hives (itchy welts on the skin), or trouble breathing, get help right away.
The American Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.
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Last Revised: August 8, 2024
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