Codeine is the most commonly used opioid medication in Canada. It is used to relieve cough and mild to moderate pain but it is addictive when used in high doses and used over a long period of time. The more you use codeine, the more your health is affected.
On this page
- About codeine
- Short-term effects of codeine
- Long-term effects of codeine
- Risks related to codeine use
- Codeine and children
- Substance use disorder and withdrawal
Codeine, like morphine, is an opioid that naturally occurs in the opium poppy. It is found in both prescription and non-prescription medications. It is used as an analgesic (pain reliever) found in medications alone or in combination with other medicinal ingredients such as acetaminophen or acetylsalicylic acid.
Codeine is often referred to as:
- Captain cody
- T1, T2, T3, T4
Codeine can be combined with additional ingredients:
- antihistamines (e.g. allergy and nighttime cold medications)
- caffeine (e.g. non-drowsy medications)
- cough syrups
- decongestants (e.g. cold medications)
- expectorants (e.g. cough medications)
- muscle relaxants (e.g. chlorzoxazone, methocarbamol)
- sedatives (e.g. butalbital)
Individuals under the age of 18 should not use products containing codeine.
Besides reducing pain, codeine is commonly used to reduce cough. Because pills and syrups often combine codeine with other ingredients, serious side effects from those ingredients may occur when used at high dosage.
Once codeine enters your system, the body breaks it down and converts it into morphine. Codeine is classified as a depressant, which means it slows down your nervous system, including your breathing rate.
Normally codeine is taken by swallowing tablets, capsules, or syrup. However, there are other methods of consuming codeine, such as injecting or snorting, which can severely increase potential health risks.
Certain lower-dose codeine products (8 mg or less per pill, 20 mg or less per 30 mL of liquid medication) can be purchased directly from a pharmacist without a prescription to temporarily treat mild or moderate pain, or as a cough suppressant. Long-term use (more than a week) of low-dose codeine products should be avoided.
In Canada, codeine is a controlled substance.
Most codeine products are not intended to be used on a long-term basis (e.g. for longer than a week). Use the smallest effective dose for the shortest period of time.
Short-term effects of codeine
The potency of codeine is unpredictable and it can be hard to tell how it will affect each individual because each person breaks down codeine differently and at different speeds. How quickly codeine affects you also depends on how you take it.
When you use codeine, especially at high doses, it reaches your brain and produces light sedation followed progressively by a feeling of well-being (euphoria) between 20 and 60 minutes later. The effects usually taper off in 2-3 hours.
Other effects are:
- going "on the nod" (being in and out of consciousness)
Codeine taken at high doses could produce the following effects that can last 3-5 hours:
- slowed breathing
- nausea and vomiting
- smaller (constricted) pupils
- feeling heavy in the arms and legs
- severe itching or warm/hot sensation on the skin
If you take codeine along with too much acetaminophen and acetylsalicylic acid (which are often combined with codeine), it can result in liver toxicity and gastrointestinal bleeding. These severe medical conditions can cause the following symptoms:
- feeling weak
- fast heartbeat
- blood in vomit
- muscle cramps
- black or tarry stool
- severe pain in the chest and/or gut
Long-term effects of codeine
Codeine has many harmful effects on your body and mind when taken repeatedly over many days, weeks, and months.
Like all opioids, codeine can cause physical dependence. To avoid symptoms of withdrawal, people who use codeine for a long time may feel the need to use it every day.
Like for other opioids, long-term codeine use can cause:
- worsening pain (known as "opioid-induced hyperalgesia")
- substance use disorder or dependence
- changing moods
- lack of emotion (apathy)
- depression, suicidal thoughts
- learning and memory problems
- difficulty in controlling impulsive behaviour
Long-term codeine or opioid use can also cause:
- increased tolerance to opioids
- severe constipation
- poor nutrition, weight loss
- sexual problems in men
- irregular menstrual cycles in women
- irregular heartbeat, cardiac arrest
Risks related to codeine use
Even the use of lower-dose codeine medications over an extended period can cause dependence, problematic use, risk of slowed breathing, and death.
As products with codeine are often combined with other medicinal ingredients, some of the risk comes from the acetaminophen or acetylsalicylic acid in the product, which are associated with liver and kidney toxicity or gastrointestinal bleeding, especially when taken at higher than recommended doses.
Like other opioids, codeine use carries a risk of overdose and poisoning if you consume more than recommended. Symptoms of overdose include:
- slow, shallow breathing
- gurgling sounds or snoring
- cold, clammy or bluish skin
- severe sleepiness or loss of consciousness
In large quantities, codeine can stop your breathing. This can be fatal.
Overdose is also more likely if you take codeine with other depressant drugs, such as:
In cases of overdose, you can use naloxone to temporarily reverse the effects of codeine and other opioids. It must be given as soon as possible, no more than 20 to 30 minutes after the codeine has been taken.
Staying at the scene of an overdose is important to help save the life of the person overdosing. The Good Samaritan Drug Overdose Act gives some legal protection for individuals who witness an overdose and call 911 or their local emergency number for help.
Codeine and children
Codeine use in children is not recommended because it can have unpredictable effects between individuals and children are more susceptible to overdose due to their smaller size. Use of opioids, such as codeine, at an early age may contribute to the development of problematic substance use later in life.
Using codeine during pregnancy can harm your unborn child. Opioid use in pregnant women is associated with:
- low birth weight
- premature delivery
- high infant mortality
- neonatal withdrawal syndrome (i.e. the baby could have withdrawal symptoms)
Ask your healthcare professional about alternatives to cough and cold products containing opioids for your children or adolescents.
Substance use disorder and withdrawal
As an opioid, codeine can cause physical dependence and substance use disorder within weeks of regular use.
More information on opioid use disorder is available.
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