Codeine: Effects, Risks, and When Use Becomes Addiction

One of the most commonly used opioid medications worldwide for treating mild to moderate pain and cough, codeine is safe when used as prescribed. In fact, it is often viewed as a “safer” or milder option compared to other opioids. However, it carries significant risks, including misuse, dependence, and addiction. 

In this article, I explain the medical uses and effects of codeine, outline its potential risks and side effects, and explain how use can cross the line into the chronic disease of addiction.

What is Codeine and What Are Its Effects?

A natural opioid derived from the poppy plant, codeine is used to treat mild-to-moderate pain and as a cough suppressant. Often it is combined with other drugs like acetaminophen (Tylenol) or ibuprofen. At prescribed doses, codeine can be safe short-term. Especially with high doses or prolonged use, it has clear risks of side effects, overdose, physical dependence, and addiction [1].

How It Works in the Body

Codeine is a “prodrug”. This means it must be metabolized by the liver (via the CYP2D6 enzyme) into morphine to produce its analgesic (pain-relieving) effects.

It works by binding to opioid receptors in the brain and spinal cord, reducing the perception of pain, and it can suppress the cough reflex in the brainstem.

Its effects include pain relief and drowsiness at prescribed doses. In higher doses, it can stimulate the brain’s reward system by releasing dopamine. This can lead to feelings of euphoria and relaxation, which contribute to its abuse potential.

Short-Term Effects at Therapeutic and High Doses

At usual prescribed doses, common effects include [2]:

• Pain relief
• Cough suppression
• Drowsiness
• Mild dizziness
• Constipation

At higher or misused doses, people may experience:

• Pronounced sedation
• “Nodding off” 
• Constricted pupils
• Slowed breathing
• Nausea
• Itchiness, 
• Feeling unusually calm or euphoric

Common Side Effects and Serious Risks

Typical side effects that may be experienced, even when taking codeine as directed, include: 

• Drowsiness
• Dizziness
• Constipation
• Nausea
• Vomiting
• Sweating 

Serious Health Risks

Serious health risks may result, including [1]:

• Respiratory Depression: A life-threatening risk of slowed or difficult breathing may result, especially at high doses, when mixed with other depressants like alcohol or benzodiazepines, or in vulnerable populations.

• The Danger of Variable Metabolism: Genetically, some people are “ultra-rapid metabolizers” (converting codeine to morphine very quickly), putting them at risk for toxicity and severe side effects even at normal doses. “Poor metabolizers” may get little to no pain relief.

• Long-Term Physical Effects: With long-term use, there is the potential for:
  • Hormonal imbalances
  • Sexual dysfunction
  • Chronic constipation and bowel problems
  • Liver and kidney damage (especially from combination products containing acetaminophen).
  • Sleep disturbance
  • Depression
  • Anxiety
  • Increased risk of seizures

When Use Becomes Addiction: The Progression

This process progresses as follows:

• Tolerance: The need to take higher doses to achieve the same effect.

• Dependence: A physiological state where the body adapts to the drug, and its absence leads to withdrawal symptoms.

• Addiction: A complex psychological and behavioral condition characterized by compulsive drug seeking, cravings, loss of control over use, and continued use despite harmful consequences.

• Risk Factors for Addiction: These increase susceptibility:
  • Personal or family history of substance abuse.
  • Pre-existing mental health disorders (anxiety, depression).
  • Chronic pain conditions.
  • Factors in the environment, such as high stress or social circles where drug use is normalized 

Signs and Symptoms of Addiction

• Physical dependence shows up as withdrawal symptoms (e.g., muscle aches, sweating, nausea, anxiety, and insomnia) when doses are reduced or missed.

• Addiction is suggested when there is loss of control and harm, such as:
  • Cravings
  • Needing larger doses
  • Preoccupation with the next dose
  • Hiding or lying about use
  • “Doctor shopping” or forging prescriptions
  • Social withdrawal
  • Neglecting responsibilities
  • Using codeine for reasons other than prescribed (e.g., to get high or cope with stress)
  • Continued use despite health, work, or relationship problems

Overdose Risk and Safety Red Flags

Especially at high doses or when combined with alcohol, benzodiazepines, or other sedating drugs, codeine can cause a life-threatening overdose. Key signs of opioid overdose, requiring emergency care and, where available, naloxone (Narcan), include: 

• Very slow or stopped breathing
• Extreme sleepiness or unresponsiveness
• Cold or bluish skin (especially lips and nails)
• Pinpoint pupils
• Gurgling or snore-like sounds suggesting a blocked airway

Withdrawal and Treatment Options

Symptoms of a dependent person stopping taking codeine include: 

• Anxiety
• Muscle aches
• Insomnia
• Sweating
• Runny nose
• Nausea
• Vomiting
• Intense drug cravings, typically starting within 24 hours of the last dose 

Pathways to Recovery

• Medical Withdrawal Management: Rather than going it alone “cold turkey”, it’s important to undergo medically supervised detoxification to safely and comfortably manage withdrawal symptoms [3].

• Medication-Assisted Treatment (MAT): To reduce opioid cravings and ease withdrawal, medications like buprenorphine can be used to help patients stabilize their lives [4].

• Therapy and Support: To address the underlying causes of addiction and build skills for long-term recovery, behavioral therapies such as Cognitive Behavioral Therapy, counseling, and support groups (such as Narcotics Anonymous) are important steps.

Why Choose Northbound Treatment Services?

At Northbound, we have extensive experience helping patients overcome their substance abuse addictions, and we have a Christian faith-based track for those wishing to participate. 

We offer a wide range of evidence-based therapies, counseling, and trauma-informed support to help you heal. We personalize each treatment plan around the needs of our patients.

The first steps are detoxification and stabilization, under 24-hour medical supervision in our Withdrawal Management center for whatever time you may require. 

Our inpatient residential program offers 24/7 live-in treatment for substance abuse. Our outpatient treatment provides a flexible step-down from our residential program, allowing you to live at home and participate for several hours a day. 

For more than 30 years, Northbound Treatment Services in California has been at the forefront of providing lifesaving, compassionate residential care and specialized services to help people from all walks of life feel better, discover themselves, and live free from addiction. 

We have facilities located throughout California to help guide you on your recovery journey. Reach out to our admissions team now.

Sources

[1] Patel P, Tharp JG, Eriator II, et al. Codeine. [Updated 2024 Feb 28]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-.

[2} Reed S. nd. Codeine Side Effects, Addiction, and Treatment. Narcotics.com

[3] Shah M, Huecker MR. Opioid Withdrawal. [Updated 2023 Jul 21]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-.

[4] Lu T, Whitley SD, Wiegand TJ, et al. Treatment of Opioid Use Disorder [Internet]. Baltimore (MD): Johns Hopkins University; 2024 Feb.