Guide to Controlling Cancer Pain

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Opioid pain medicines

These medicines are used alone or with non-opioids to treat moderate to severe pain. Opioids are much like natural substances (called endorphins) made by the body to control pain. These medicines were once made from the opium poppy, but today many are synthetic, that is, they’re man-made in a lab.

Common opioids by generic name

Here are some of the opioids used in cancer care. The more common brand names are added in parentheses. An “ER” behind the name of any of these drug names stands for “extended release,” and is a sign that the drug is taken on a regular schedule to treat chronic pain.

  • Codeine*
  • Hydromorphone (Dilaudid)
  • Levorphanol (Levo-Dromoran)
  • Methadone (Dolophine, Methadose)
  • Morphine (Apokyn, Avinza, Kadian, MS-Contin, and others)
  • Oxycodone* (OxyContin, OxyIR, Roxicodone)
  • Hydrocodone*
  • Oxymorphone (Opana)
  • Fentanyl (Duragesic, Actiq, Fentora, Lazanda, and others)

*Common combination opioid and acetaminophen or NSAID drugs:

  • Codeine may be added to aspirin or acetaminophen. For instance, Fiorinal with codeine has aspirin; Fioricet with codeine, Tylenol #3, and Tylenol #4 all contain acetaminophen.
  • Oxycodone may be added to aspirin, acetaminophen, or ibuprofen. For instance, Percodan has aspirin in it; Percocet, Roxicet, Roxilox, Oxycet, and Tylox all have acetaminophen; Combunox has ibuprofen.
  • Hydrocodone may be added to acetaminophen or ibuprofen. For instance, Zydone, Norco, and Lortab all contain acetaminophen; Vicoprofen and Reprexain have ibuprofen.

If you’re taking a combination pain medicine, be sure you know what drugs are in each pill.

Opioid tolerance

People who take opioids for pain sometimes find that over time they need to take larger doses. This may be due to an increase in the pain or the development of drug tolerance. Drug tolerance is when your body gets used to the opioid you’re taking, and it takes more medicine to relieve the pain as well as it once did. Many people do not develop a tolerance to opioids. But if tolerance does develop, usually small increases in the dose or a change in the kind of medicine will help relieve the pain.

Increasing the doses of opioids to relieve increasing pain or to overcome drug tolerance does NOT mean that a person is addicted.

How to get proper pain relief with opioids

When a medicine doesn’t give you the pain relief you need, your doctor may prescribe a higher dose or tell you to take it more often. When your cancer care team is working closely with you, doses of strong opioids can be raised safely to ease severe pain. Do not increase the dose of your pain medicine on your own. If dose changes don’t work, your doctor may prescribe a different drug or add a new drug to the one you’re taking.

If your pain relief isn’t lasting long enough, ask your doctor about extended-release medicines that come in pills and patches. These can control your pain for a longer period of time.

If your pain is controlled most of the time, but you sometimes have breakthrough pain, your doctor may prescribe a fast-acting medicine or immediate-release opioid that will give you faster pain relief right when it’s needed.

Be safe when taking opioids.

Doctors carefully watch you and adjust the doses of pain medicine so you don’t take too much. For this reason, it’s important that only one doctor prescribe your pain medicines. If you’re working with 2 or more doctors, be sure that one does not prescribe opioids for you without talking to the others about it.

If you drink alcohol or take tranquilizers, sleeping pills, antidepressants, antihistamines, or any other medicines that make you sleepy, tell your doctor how much and how often you do this. Combinations of opioids with alcohol or tranquilizers can be dangerous. Even small doses may cause problems. Using such combinations can lead to overdoses and symptoms such as weakness, trouble breathing, confusion, anxiety, or more severe drowsiness or dizziness.

Side effects of opioids

Not everyone has side effects from opioids. The most common side effects are usually drowsiness, constipation, nausea, and vomiting. Some people might also have dizziness, itching, mental effects (such as nightmares, confusion, and hallucinations), slow or shallow breathing, or trouble passing urine.

Many side effects from opioid pain medicine can be prevented. Some of the mild ones such as nausea, itching, or drowsiness, often go away without treatment after a few days, as your body adjusts to the medicine. Let your cancer care team know if you’re having any side effects and ask for help in managing them.

Here are a few of the more common side effects:


When you first start taking them, opioids may cause drowsiness, but this usually goes away after a few days. If your pain has kept you from sleeping, you may sleep more for a few days after starting opioids while you “catch up” on your sleep. Drowsiness will also lessen 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.

Sometimes it may be unsafe for you to drive a car, or even to walk up and down stairs alone. Do not do anything that requires you to be alert until you know how the medicine affects you.

Here are some ways to handle drowsiness:

  • Wait a few days and see if it goes away.
  • Check to see if other medicines you’re taking can also cause drowsiness.
  • Ask the doctor if you can take a smaller dose more often or an extended-release opioid.
  • If the opioid is not relieving the pain, the pain itself may be tiring you out. In this case, better pain relief may lead to less drowsiness. Ask your cancer care team what you can do to get better pain relief.
  • Sometimes a small decrease in the dose of an opioid will still relieve your pain without causing drowsiness. If the drowsiness is very bad, you may be taking more medicine than you need. Talk to your doctor about lowering the amount you’re taking.
  • Ask your doctor about changing to a different medicine.
  • Ask your doctor if you can take a mild stimulant such as caffeine during the day.
  • If drowsiness is bad or if it suddenly starts to be a problem after you’ve been taking opioids for a while, call your cancer care team right away.


Opioids cause constipation in most people. This is because opioids slow the movement of stool through the intestinal tract, which allows more time for water to be absorbed by the body. The stool then becomes hard. It’s best to start a laxative, stool softener, or other treatment to keep your bowels moving when you start taking opioids. Constipation can often be prevented or controlled.

After checking with your cancer care team, try the following to prevent constipation:

  • Talk with your team about stool softeners and laxatives. Ask how often and how much you should take.
  • Drink plenty of liquids. Eight to 10 8-ounce glasses of fluid each day can help keep your stools soft. This is a very important step – if your stool is dry, it will be hard to pass.
  • Eat foods high in fiber or roughage such as uncooked fruits (with the skin on), vegetables, and 100% whole-grain breads and cereals.
  • Add 1 or 2 tablespoons of unprocessed bran to your food. This adds bulk and promotes bowel movements. Keep a shaker of bran handy at mealtimes to make it easy to sprinkle on foods. Be sure to drink plenty of water when you eat bran so that it softens in the bowel.
  • Exercise as much as you can. Talk with your doctor about what kind of exercise is best for you. Walking is often a good start if you haven’t exercised recently.
  • Eat foods that have helped you relieve constipation in the past.
  • If you haven’t been getting out of bed, try to use the toilet or bedside commode when you have a bowel movement, even if that’s the only time you get out of bed.

If you’re still constipated after trying all the above measures, ask your doctor about changing your stool softener or laxative. Check with your cancer care team before taking any laxative or stool softener on your own. If you haven’t had a bowel movement for 2 days or more, call your team.

Nausea and vomiting

Nausea and vomiting caused by opioids will usually go away after a few days of taking the medicine. These tips may help:

  • If you have more nausea when you’re up or walking around but not when you’re lying down, stay in bed for an hour or so after you take your pain medicine. This type of nausea is like motion sickness. Sometimes over-the-counter medicines such as meclizine (Bonine or Antivert) or dimenhydrinate (Dramamine) help this type of nausea. Check with your cancer care team before taking these medicines, since they can cause problems for some people.
  • If pain itself is causing the nausea, using opioids to relieve the pain usually makes the nausea go away.
  • Medicines that relieve nausea can be prescribed if you need them. Talk with your cancer care team if you can’t hold down foods or liquids for a full day, or if nausea lasts more than a few days.
  • Ask your team if the cancer, another medical problem, steroids, chemo, or other medicines might be causing your nausea. Constipation may also worsen nausea.

Some people think they’re allergic if they have nausea after they take an opioid. Nausea and vomiting alone usually are not allergic reactions. But a rash or itching along with nausea and vomiting may be an allergic reaction. If this happens, stop taking the medicine and call your cancer care team right away. If you have swelling in your throat, hives (itchy welts on the skin), and/or trouble breathing, get help right away.

When you no longer need opioids

You should not suddenly stop taking opioids. People who stop taking opioids are usually tapered off the medicine slowly so that their bodies have time to adjust. If you stop taking opioids suddenly 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 to a few weeks. Again, slowly decreasing your opioid dose over time usually keeps these kinds of symptoms from happening. Check with your doctor about the best dose schedule for tapering off your pain medicines.

Last Medical Review: 07/15/2015
Last Revised: 07/15/2015