Taking pain medicines safely

Talk to your doctor or pharmacist about how to take your medicines and be sure to follow the instructions. It is important to take pain medicines exactly as prescribed by your healthcare team. Following their directions will help keep the level of medicine constant and make sure that pain is controlled. The following are tips for taking pain medicines safely.

Know how to take pain medicines

Pain medicines can be taken in many different ways, depending on what works best for a situation.

Oral medicines

The most common way of taking pain medicine is by mouth (orally). Oral medicines are in the form of a pill, tablet, capsule or liquid. Check with your doctor or pharmacist to see if it is OK to crush or break your pain pills. Some pills, tablets or capsules are made with a special coating for slow release of the drug and that coating should not be broken. Some pain medicines don’t have to be swallowed. They may be placed under the tongue (sublingual) or given as a lozenge that you suck on. These drugs are absorbed through the inside of the mouth.

If you have a feeding tube in place, your doctor may give you painkillers that are liquid or that dissolve (are soluble) so they can be given directly into your stomach through the tube.

Topical medicines

Some medicines may be applied to the skin as a cream, gel or ointment. These drugs are called topical or transdermal. They move through the skin into the bloodstream. They are used for some types of pain on the surface of the body.

Sometimes a patch is used to deliver a constant amount (dose) of pain-relieving medicine. It may take a day or longer for medicines given in this way to relieve or control the pain, so your healthcare team may also give you breakthrough doses of medicine.

Topical anesthetics numb the skin and make it feel frozen. They can be used to ease pain from damaged nerves near the surface of the body. For example, a mixture of lidocaine (Xylocaine) and prilocaine (EMLA cream) may be used as a topical anesthetic to numb the skin before a needle stick or before minor surgical or diagnostic procedures.

Topical nonsteroidal anti-inflammatory drugs (NSAIDs) may relieve the pain of swollen joints.


Injections are given through needles. When a medicine is injected, the body absorbs and uses it quickly. Pain medicines may be given by injection if you have difficulty swallowing or your pain needs to be relieved or controlled right away. There are many ways to inject medicines into the body. Injections for pain are usually given by your healthcare team.

Pain pump

A pain pump can be used to help relieve severe pain. It is a computerized machine outside of your body that is connected to a tube going into a vein (intravenous) or under the skin (subcutaneous). Pain pumps are programmed to deliver a specific amount of a drug over a certain amount of time. Once that limit is reached, no more medicine is released.

Some pumps are small and portable so they can be used at home. Certain types of pain pumps let you give yourself medicine when you need it (called patient-controlled analgesia or PCA). Others may be set to give a constant flow of medicine. With these types of pumps, you can push the button for an extra dose of medicine if you need it.

Know when to take your pain medicines

Pain medicines usually need to be taken on a regular schedule. Do not skip doses, even if you are not having pain. Don’t stop taking pain medicines, even if it does not seem to help with the pain right away. It can take some time, sometimes up to weeks, for these drugs to be effective.

Tell your healthcare team if pain returns before the next dose of medicine. Sometimes pain will get worse at certain times of the day or with certain activities. The pain may “breakthrough”the relief given by the regular doses. When this happens, your healthcare team may give an extra (breakthrough) dose of medicine or a different drug to deal with this type of pain. Don’t wait until pain is severe before taking medicine for breakthrough pain.

Tell the healthcare team if pain medicines aren’t working

It may take a few days for your healthcare team to figure out the right amount of medicine and how it needs to be taken to ease or control pain. Regular and ongoing pain assessment is very important. It may help to keep a record of the pain medicines you take, how often you take them and how well they control your pain. Tell them what helps to relieve your pain and what doesn’t. Let them know about any changes in the pattern of your pain, such as if it comes back more often, if it becomes worse or if new pain develops. This will help the healthcare team determine the best way to manage your pain. The plan for treating pain may need to change over time.

Tell the healthcare team about any side effects

It’s important to tell your healthcare team about any side effect you have. Keep a copy of the drug information sheets that come with your prescriptions. These describe the side effects of each drug. Ask your doctor or pharmacist about what side effects to watch for and who or when to call if you experience side effects.

Some pain medicines, such as opioids, can cause changes in mental alertness at first. After taking the same dose of a medicine for a few days, this should improve. Talk to the healthcare team if you have problems with mental alertness or carrying on normal activities after a few days. You may need to avoid certain activities, such as driving or using power tools, when taking pain medicines. Talk to your healthcare team about what activities are safe when taking pain medicines.

Keep a list with you of all the medicines you are taking

Some drugs do not work well together. It’s important to keep a list of and tell the healthcare team about any other medicines you are taking, including:

  • prescription drugs
  • over-the-counter drugs
  • vitamin or mineral supplements
  • herbal remedies and other natural health products
  • complementary or alternative therapies

Keep track of all the medicines you are taking

You may be given prescriptions for different medicines from different doctors. Keeping track of all your medicines, including pain medicines, can be overwhelming.

Always read the entire label on the prescription to make sure you are taking the right dose at the right time. Keep the drug information sheets that come with the prescription as they often include important details on how to take the medicine and any side effects.

Try to take your medicines at the same time every day. It may be helpful to use your phone or an alarm to remind you. You may also ask friends or family to remind you.

Keep track of when you have taken your medicines using a chart, pill calendar or phone calendar. There are also apps for your phone that you can use to keep track of taking your medicines. Some people find it helpful to use a weekly pill case.

Make sure you have enough pain medicines

Prescriptions are needed for almost all pain medicines. It can take a few days to get pain medicines if you run out. Try to keep at least a week’s supply of pain medicines on hand. If you are going out of town or travelling, always make sure you have enough pain medicines with you.

Check with your healthcare team before stopping any pain medicines

Talk to the healthcare team before you stop taking a pain medicine for any reason. Don’t just stop taking the medicine. A sudden change in the level of drug in the body may cause unpleasant side effects.

If you have any concerns about a drug or any side effects it may be causing, talk to your healthcare team about other options for managing pain. They may lower the doses or stop the drug altogether when cancer treatments, such as radiation therapy or surgery, relieve the pain. If your healthcare team decides to stop the drug, they will slowly lower the dose over time, until it is low enough to be stopped completely. The dose may also be lowered when the pain is controlled but the drug is causing drowsiness (sedation).

Ask questions

Finding the right answers to any questions you have about pain medicines is important and can help in making decisions. Ask your healthcare team any questions you have about pain medicines, including:

  • How much medicine should I take? How often should I take it?
  • If my pain doesn’t go away, can I take more medicine? How much more should I take?
  • When should I call the doctor? Should I call before taking more medicine?
  • How long does the medicine last?
  • What if I forget to take my medicine or take it later than I was supposed to?
  • Should I take my medicine with food?
  • How much liquid should I drink with my medicine?
  • How long does it take for the medicine to work?
  • Is it safe to drive when taking this medicine?
  • Are there any drugs that I need to avoid while taking this pain medicine? Is it safe to drink alcohol when taking it?
  • What other medicines can I use with this pain medicine?
  • Does this drug cause any side effects? What can I do to prevent or cope with side effects?

Expert review and references

  • American Cancer Society. Cancer Pain. 2015.
  • American Society of Clinical Oncology. Managing Cancer-Related Pain: A Guide for Patients, Families and Caregivers. 2017.
  • Cancer Care Nova Scotia. Guidelines for the management of cancer-related pain in adults. Halifax: Cancer Care Nova Scotia; 2005.
  • Symptom management pocket guides: pain. Cancer Care Ontario. Cancer Care Ontario. Toronto, ON: Cancer Care Ontario; 2010.
  • Cancer Care Ontario's symptom management guides-to-practice: pain. Cancer Care Ontario. Cancer Care Ontario. Toronto, ON: Cancer Care Ontario; 2010.
  • Cancer Research UK. Cancer and pain control. Cancer Research UK; 2014: http://www.cancerresearchuk.org/.
  • Ferrell, B. R . Pain management. Pollock, R. E., Doroshow, J. H. & Khayat, D. et al. (Eds.). UICC Manual of Clinical Oncology. 8th ed. New Jersey: John Wiley & Sons, Inc; 2004: 35: pp. 771-782.
  • Foley, K. M., Back, A. & Bruera, E., et al. (Eds.). When the Focus Is on Care: Palliative Care and Cancer. Atlanta: American Cancer Society; 2005.
  • Lavoie Smith, E . Cancer pain. Varricchio, C., Pierce, M., Hinds, P. S., & Ades, T. B. A Cancer Source Book for Nurses. 8th ed. Sudbury, MA: Jones and Bartlett Publishers; 2004: 23: pp. 349-360.
  • Cancer pain. Macmillan Cancer Support. Macmillan Cancer Support. London, UK: Macmillan Cancer Support; 2011.
  • National Cancer Institute . Cancer Pain (PDQ®) Health Professional Version . 2017 : https://www.cancer.gov/.
  • National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Adult Cancer Pain (Version 2.2017).
  • Paice, J. A . Pain. Yarbro, C. H., Frogge, M. H. & Goodman, M. Cancer Symptom Management. 3rd ed. Sudbury: Jones and Bartlett Publishers; 2004: 6: pp. 77-96.
  • Robbins, W., Rosenbaum, E. H. and Rosenbaum, I. R . Pain control. Rosenbaum, E. H. & Rosenbaum, I. Supportive Cancer Care: The Complete Guide for Patients and Their Families. 3rd ed. Naperville: Sourcebooks, Inc.; 2001: 9: pp. 83-86.
  • Watson P, Watt-Watson J . Pain medications . Canadian Pain Society and Canadian Pain Coalition . Pain Resource Centre . 2012 .

Medical disclaimer

The information that the Canadian Cancer Society provides does not replace your relationship with your doctor. The information is for your general use, so be sure to talk to a qualified healthcare professional before making medical decisions or if you have questions about your health.

We do our best to make sure that the information we provide is accurate and reliable but cannot guarantee that it is error-free or complete.

The Canadian Cancer Society is not responsible for the quality of the information or services provided by other organizations and mentioned on cancer.ca, nor do we endorse any service, product, treatment or therapy.

1-888-939-3333 | cancer.ca | © 2024 Canadian Cancer Society