Opioid Pain Medications

November 2009

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The Issue

Opioid pain medications include a broad range of drugs, such as morphine, codeine and oxycodone. They are marketed under many different brand names, including Percocet®, OxyContin®, and Tylenol No.1® (see the Need More Info? section below for a list of common prescription opioid pain medications approved for sale in Canada.)

When used as directed, opioid pain medications are effective and the side effects (e.g., drowsiness, nausea, constipation, etc.) are generally manageable. However, abuse of these medications can have serious health effects and may lead to addiction.


There are many types of pain medications on the market, including acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDs, such as acetylsalicylic acid (ASA) and ibuprofen), corticosteroids (often called steroids) and opioids. Different types of pain medications help to manage different kinds of pain, and like other medicines, they all carry some risk.

Opioid pain medications are generally used to manage moderate to severe pain, which may be acute (e.g., short-term pain following surgery) or chronic (e.g., long-term pain associated with a medical condition, such as different types of cancers). They may also be used to control moderate to severe cough, control diarrhea, and treat addictions to other opioids, including street drugs like heroin.

Opioid medications come in many forms, including tablets, capsules, syrups, solutions, nasal sprays, skin patches and suppositories. The strength of the opioid in these medications varies greatly, and most are available in Canada by prescription only. However, some products containing very low doses of the opioid codeine, combined with at least two other medicinal ingredients, can be purchased directly from a pharmacist. (See the Overdose section below for information about risks associated with taking more than the recommended dose of opioid medications, including those sold over-the-counter.)

Side Effects of Opioid Pain Medications

Like other medicines, opioid pain medications have side effects, even when used as directed. The short-term effects may include:

  • drowsiness
  • constipation
  • light-headedness and dizziness
  • mild anxiety
  • dry mouth
  • headaches
  • nausea
  • reduced appetite
  • confusion

In addition, a person taking opioid pain medication may experience the following:

  • vomiting
  • rash and itchiness
  • pinpoint pupils
  • difficult urination
  • burning sensation on the skin
  • cold clammy skin
  • trouble with breathing, such as slow or shallow breathing

Potential for Abuse and Addiction

In addition to treating pain, opioid medications can also cause euphoria (a "high"), and this makes them prone to abuse. Patients taking opioid medication for pain may or may not experience a high. However, all opioids have the potential to be addictive. Addiction refers to the compulsive use of a substance, despite its negative consequences. People with a personal or family history of substance abuse, including alcohol, may be at higher risk of addiction to opioid pain medications.

Over the past decade, abuse of and addiction to opioid pain medication has emerged as a public health issue. Abuse of these medicines can cause serious health effects for the user, including a risk of death from an overdose. Drug abuse and addiction to any substance may also cause problems at work or school, and can result in the breakdown of family relationships. In addition, drug abuse can result in financial costs to society for things like healthcare, crime, and lost productivity.

Because of their psychoactive properties (properties that affect the mind and mental processes) and their potential for abuse, opioid pain medications are regulated in Canada under the Controlled Drugs and Substances Act (CDSA). Under the CDSA, it is illegal to:

  • possess opioid pain medications unless you are a patient with a prescription from a licensed health care professional;
  • sell or even give away your prescription opioid pain medication to someone else;
  • "double doctor," i.e., seek a prescription for an opioid pain medication from more than one doctor in a short period of time without the doctor knowing that you have already obtained a prescription from another doctor.

Other Safety Concerns

An overdose of opioid pain medication is very dangerous, as it can lead to slowed breathing and may result in death if left untreated. An accidental overdose may occur if the medication is taken improperly. For example, time-release tablets are meant to be swallowed whole. Crushing or breaking these pills before taking them can lead to overdose because too much of the opioid is released all at once.

Some opioid pain medications, including over-the-counter products that contain low doses of codeine, also contain acetaminophen or acetylsalicylic acid ( ASA). Taking more than the recommended amount of these medications can lead to serious health effects. Many products contain the same medicinal ingredient(s); e.g., acetaminophen, and combined use could lead to overdose. Acetaminophen overdose can cause fatal liver damage, while acetylsalicylic acid ( ASA) overdose can result in delirium, convulsions, coma, or death due to respiratory failure.
Drug Interaction
Interactions may occur if opioid pain medications are taken with other prescription and over-the-counter drugs, alcohol, or illegal drugs. The effects of interactions can be severe. For example, it is dangerous to take an opioid while drinking alcohol or taking other drugs that depress the central nervous system, such as sedative medications. This can lead to slowed breathing, which may be fatal.
Physical Dependence / Withdrawal
Long-term use of opioid pain medications leads to physical dependence. This does not necessarily mean that a person is addicted. Physical dependence is a natural reaction that occurs in the body when certain drugs are used. If opioid use is suddenly stopped, a dependent person will have withdrawal symptoms, which may include anxiety, muscle and bone pain, diarrhea, vomiting, poor appetite, restless sleep, chills (goose bumps), shakiness, and twitching muscles. The severity and duration of withdrawal symptoms depends on the type and amount of medication used and for how long. These symptoms can be minimized if patients consult their health care professional about a schedule to reduce doses gradually when it is time to reduce or end the use of opioid pain medications.

Minimizing Your Risk

The following steps will help minimize the risks of using opioid pain medications:

  • Before using opioid pain medications, discuss the benefits and risks with your healthcare provider:
    • Tell your healthcare professional and pharmacist about other health products and substances you are using, including prescription and over-the-counter drugs, natural health products, alcohol, and illegal drugs. This will help avoid potentially harmful drug interactions.
    • Discuss any concerns you may have regarding a personal or family history of substance abuse, including alcohol.
  • Read the label and take opioid pain medication exactly as directed. Take the right dose at the right time, and find out from your doctor or pharmacist what to do if you miss a dose. Remember, crushing or cutting open a time-release pill destroys the slow release of medication and can lead to an overdose with serious health effects.
  • Follow the other directions that may come with your medication, such as not driving, and avoiding the use of alcohol.
  • Store opioid pain medication in a safe place, out of the reach of children and teenagers. Keep track of the amount of opioid medication that you have.
  • Never share prescription opioid pain medication with anyone else, as this is illegal and may cause serious harm to the other person.
  • Return any unused opioid pain medication to the pharmacy for safe disposal. This will help prevent its diversion for illegal use. It will also help protect the environment. Drugs should never be disposed of in the home (e.g., in the sink, toilet or trash).

In addition, Health Canada strongly advises against taking any prescription medication that has not been prescribed for you by your health care professional.

Health Canada's Role

Health Canada regulates opioid pain medications under the Food and Drugs Act and the Controlled Drugs and Substances Act. Regulation involves reviewing scientific information about the safety, effectiveness, and quality of these medications before they are authorized for sale in Canada, as well as working to prevent opioid pain medications from being diverted for illegal use.

Health Canada also monitors the safety of health products after they have been approved for sale. Manufacturers are required to provide Health Canada with reports of serious adverse effects for health products they sell in Canada, and consumers and health care providers are encouraged to report adverse reactions via the MedEffect Web site. (See below for a link to MedEffect.)

Need More Info?

For more information see Health Canada's Opioid Pain Medications FAQs

You can find more information about specific opioid pain medications by doing an online search of Health Canada's Drug Product Database

When you find the product you are looking for, check to see if there is a product monograph. If there is, open it and scroll down to "Part III: Consumer Information."

It's Your Health articles:

And, visit the  Centre for Addiction and Mental Health and search for these resources: "Do You Know...Opioids," "Oxycontin: Straight Talk" and "Is it Safe for My Baby - Pain Medications."

In addition, see the U.S. Food and Drug Administration (FDA):  A Guide to Safe Use of Pain Medicine

To report an adverse drug reaction, go to the MedEffect Web section

For more on Health Canada's role, visit the following Web sections:

For additional articles on health and safety issues go to the It's Your Health Web section
You can also call toll free at 1-866-225-0709 or TTY at 1-800-465-7735*

Original: November 2009
©Her Majesty the Queen in Right of Canada, represented by the Minister of Health, 2009

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