Skip to content



Codeine is an opioid medication used to relieve mild pain or cough. It has both widespread availability and a high risk for misuse.

What Is Codeine?

Codeine is an opioid often prescribed to reduce coughing and treat mild to moderate pain. It was originally extracted from the seeds of the opium poppy plant but is now synthetically metabolized into a morphine-type substance. Although it is related to morphine, it is significantly less potent as a pain reliever. Still, it is the most commonly used opioid medication worldwide.


The combination of codeine with promethazine cough syrup is commonly referred to as lean. This substance is a result of mixing codeine cough syrup with soda or alcohol. Promethazine is a sedative agent and, when combined with codeine, can result in dangerous effects of sedation and euphoria.

What Is Codeine Used For?

Codeine is prescribed to treat mild to moderate pain, cough, and, at times, persistent diarrhea. It is available in tablet form and as a syrup.

It is available by prescription only and is primarily used in the short term. It may be combined with acetaminophen (Tylenol #3), promethazine (anti-nausea and sedation), chlorpheniramine, pseudoephedrine (decongestant), and others.

How Does It Work?

Although codeine is an opioid, it has mild pain-relieving properties and is a weak agonist on pain receptors in the central nervous system. It is considered a “pro-drug,” with only 1/10 the potency of morphine.

A pro-drug requires the body to convert the initial drug into another substance to be effective. Codeine is unique in that different people may respond to codeine differently depending on their specific genetic metabolism. People fall into three groups in how they metabolize codeine:

  • Poor metabolizers (PM)
  • Extensive metabolizers (EM)
  • Ultra-rapid metabolizers (UM)

When all three groups take the same amount of codeine, they will have different levels of codeine metabolized in their system. Each of these three metabolizers may have varying amounts of analgesic activity from the morphine-type metabolite. Poor metabolizers will have only about a 10% effect, EM will have about 40%, and UM will have about 51% of the pain-relieving properties of the morphine metabolite.

This is important to understand, as codeine can affect people differently. One person may have very little respiratory depression or pain relief from codeine, while another person may stop breathing or die with the same dose of codeine. This highlights one of the key risks of recreational codeine use. It may also explain how different people feel after taking the drug.

What Are The Side Effects Of Taking Codeine?

Since codeine is an opioid, the side effects are similar to what you can see with other types of opioid use. Some side effects can be mild, while others are severe. Some common side effects of codeine are:

  • Sedation
  • Respiratory depression
  • Confusion
  • Euphoria
  • Irritability
  • Constipation
  • Abdominal bloating

Codeine can affect everyone differently depending on prior use and use of other medications.

What Are The Risks Associated With Codeine?

Even though codeine has medicinal uses, it also binds to the receptors in the brain that regulate pain and pleasure and can give users a feeling of deep relaxation and euphoria. Inappropriate use or repeated long-term usage can lead to physical dependence on codeine and eventually lead to addiction.

In countries outside the U.S., codeine-containing cough syrups are available without a prescription. The increased availability has led to cheaper and more plentiful supplies in the U.S. This may also give the mistaken perception that codeine cough syrups are not harmful.

Signs And Symptoms Of Codeine Addiction

Codeine addiction can develop over time with repeated and regular use. To avoid experiencing unpleasant withdrawal symptoms, people may take the drug regularly, which can lead to addiction. Some signs and symptoms of codeine addiction are:

  • Obtaining a regular supply of codeine becomes more and more important.
  • Lying about medical conditions for prescriptions.
  • Using other people’s prescriptions.
  • Experiencing mood swings.
  • Minimizing the role codeine usage plays in a person’s life.
  • Increasing time spent sleeping.
  • Using laxatives to relieve chronic constipation.

Paid Advertising. We may receive advertising fees if you follow links to the BetterHelp site.

Online Addiction Counseling

Get professional help from an online addiction and mental health counselor from BetterHelp.

Get Matched
Begin Therapy
  • Personalized Matching Process
  • Easy Online Scheduling
  • 30,000+ Licensed Therapists


What Is The Difference Between Codeine Abuse And Addiction?

One key difference between codeine abuse and addiction is the ability to stop using. Addiction describes a cycle of obtaining and using codeine to avoid withdrawal and avoid living without codeine. The behaviors of the person using codeine change so that their daily life is impacted.

Codeine abuse can lead to addiction, and at times, it can be unclear if someone is addicted to codeine. When use stops being voluntary, it is clear that addiction may be taking hold.

Signs Of Overdose

Codeine use can cause an immediate overdose in someone who is an ultra-metabolizer, or an overdose may develop after significant codeine use. Signs and symptoms of codeine overdose may include:

  • Blue fingernails and lips
  • Decreased or shallow breathing
  • Confusion
  • Constipation
  • Drowsiness
  • Dizziness
  • Itching
  • Low blood pressure or weak pulse
  • Nausea and vomiting
  • Muscle twitching
  • Loss of consciousness
  • Tiny pupils
  • Stomach and intestine spasms

If you suspect someone is overdosing on codeine, call 911 right away.

Codeine overdose can be reversed with naloxone, but only if help arrives in time. If a person overdoses on codeine mixed with other medications, including acetaminophen, longer-term effects on the liver may result, which may require a liver transplant.

What Are The Symptoms Of Codeine Withdrawal?

If you have been using codeine regularly for several weeks or longer, you may be at risk of developing withdrawal symptoms. If you stop using codeine suddenly or have a longer interval between uses, you may experience unpleasant symptoms, such as:

  • Restlessness
  • Irritability
  • Widened pupils
  • Teary eyes
  • Chills
  • Nausea
  • Loss of appetite
  • Vomiting/diarrhea
  • Stomach cramps
  • Muscle aches or backache

Codeine Drug Rehab Treatment

Codeine abuse can be challenging to identify, with milder outward signs and symptoms than other drugs. It is also legal, which makes it harder to identify more obvious, alarming behaviors.

Codeine drug rehab treatment is available along with appropriate detox to minimize withdrawal effects.

Reach Out Today

An addiction to codeine can lead to severe and life-threatening side effects for those who misuse and abuse the drug.

If you or a loved one is seeking support for codeine addiction, help is available. Reach out to a treatment provider today to explore your treatment options, risk-free.

Start Your Recovery Today

Help is available. Explore your recovery options and break free from addiction.