Codeine Addiction: Side Effects, Signs of Misuse, and Treatment

What is Codeine?

Codeine is an opioid often used as a pain reliever and cough suppressant.¹ Available in tablet, capsule, and liquid forms, codeine is frequently found in combination with other substances such as acetaminophen (a fever and pain medication), guaifenesin (an expectorant), and promethazine (an antihistamine).^2-5

Along with therapeutic uses, codeine can be misused for its rewarding opioid effects such as relaxation and euphoria.⁶  In fact, according to the  2022 National Survey on Drug Use and Health, of the more than 19.8 million people aged 12 and older who used codeine products in the past year, 9.3% (or more than 1.8 million people) misused the drug.⁷ And among this same age group and timeframe, almost 1 in 4 people who misused prescription pain relievers misused codeine.⁸

Not surprisingly, codeine can be addictive like many other opioids. The substance attaches to and activates opioid receptors throughout the brain to modify pain signals. In turn, this opioid activation is associated with an increase in dopamine activity in the brain, which can significantly reinforce the act of taking the opioid and ultimately prompt people to repeat the experience.⁶

Given its addictive properties, codeine is a controlled substance that in its various formulations falls under several drug schedules from the Drug Enforcement Administration (DEA). Codeine is classified as a Schedule II drug when used alone, a Schedule III drug when 90 milligrams or fewer are used (e.g., Tylenol with Codeine), and a Schedule V drug when fewer than 200 milligrams are used in combination with some other substances.^9,10 Schedule II drugs have a high potential for abuse and severe dependence; whereas, Schedule III and V drugs have a respectively lower potential for these outcomes.¹⁰

Historically, a popular method of misuse involved a drink sometimes referred to as “lean” or “sizzurp.” This combination “cocktail” often comprises prescription cough syrup containing codeine and promethazine that’s then mixed with sweet flavorings, such as candy or soda.^2,11

What are the Side Effects of Codeine?

Various drug formulations that include codeine (e.g., codeine and acetaminophen, codeine and promethazine, etc.) can have slightly different side effects. However, some of the more common adverse reactions involving codeine products include:^3,4

• Sedation/drowsiness.
• Impaired mental and physical performance.
• Dizziness/lightheadedness.
• Sweating.
• Dry mouth.
• Nausea.
• Vomiting.
• Constipation.
• Shortness of breath.

Additional adverse reactions, which vary by substance combinations, can include:³

• Unease/dissatisfaction (i.e., dysphoria).
• Abdominal pain.
• Skin itching (i.e., pruritus).
• Physiological dependence and withdrawal.
• Addiction development.

Of note in situations of misuse involving certain combination formulations, high doses of acetaminophen (a substance often combined with codeine) is associated with acute liver failure that has resulted in death in some cases.⁴ Additionally, the misuse of other codeine-product combinations, such as those that include aspirin, may increase the risk of coagulation abnormalities, bleeding, and metabolic acidosis.¹²

Codeine overdose—like that of other opioid overdoses—can lead to respiratory depression, respiratory arrest, coma, brain damage, and death.^3,6

Dangers of Mixing Alcohol and Codeine

The misuse of more than one substance within a short period of time—a practice known as polysubstance use—is never safe. But mixing codeine with alcohol and/or other central nervous system (CNS) depressants (e.g., benzodiazepines, sedative-hypnotics, tranquilizers, etc.) is especially dangerous.^3,13

Any type of polysubstance use can have unpredictable effects, with some substance combinations resulting in more potent effects than either drug alone.¹³ However, CNS depressants all suppress the respiratory system, and when combined (such as with alcohol and codeine), the substances can significantly slow breathing, damage various organs, and potentially lead to death.^14,15

Signs and Symptoms of Codeine Addiction

Prolonged problematic use of opioids such as codeine may be accompanied by functional changes in the brain that can reinforce compulsive misuse. Eventually, this use can result in the development of opioid addiction or, in diagnostic terms, an opioid use disorder.¹⁶

So how does someone know if they have a codeine addiction? Healthcare and addiction professionals employ the following criteria from the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) to diagnose opioid use disorders:¹⁷

• Taking opioids for longer periods of time or in larger amounts than intended.
• Being unable to cut down or stop substance use.
• Spending a lot of time obtaining, using, and recovering from the effects of the substance.
• Experiencing cravings, or intense desires or urges for the substance.
• Failing to fulfill obligations at home, work, or school due to substance use.
• Continuing substance use despite having interpersonal or social problems that are caused or worsened by opioid use.
• Giving up social, recreational, or occupational activities due to substance use.
• Using the substance in risky or dangerous situations.
• Continuing opioid use despite having a physical or mental problem that is probably due to substance use.
• Developing tolerance or needing more of the substance to achieve previous effects.*
• Suffering from withdrawal, meaning that unpleasant symptoms occur when the individual stops using their substance of choice.*

*These criteria are not considered met in those solely taking codeine therapeutically under appropriate medical supervision.

Signs of Codeine Overdose

When someone overdoses on codeine, the most immediately life-threatening effect is severe respiratory depression.^4,18 Additional physical signs of codeine overdose include:⁴

• Diminished levels of consciousness.
• Pronounced drowsiness progressing to stupor or coma.
• Constricted pupils.
• Limp skeletal muscles.
• Cold, clammy skin.

If other substances are mixed with codeine, additional overdose symptoms may be present such as the following, which are related to acetaminophen* or promethazine** overdose:^3,4

• Liver cell death (i.e., hepatic necrosis) (which can include symptoms such as nausea, vomiting, malaise, and excessive sweating).*
• Damage to tubule cells of the kidneys.*
• Hypoglycemic coma.*
• Coagulation defects.*
• CNS depression.**
• Low blood pressure.**
• Respiratory depression, unconsciousness, and sudden death.**

Symptoms of Codeine Withdrawal

When a person has become physiologically dependent on a drug, withdrawal symptoms may occur when they stop or significantly reduce substance use.¹⁶ Codeine is on a short list of substances commonly associated with clinical withdrawal symptoms; others include heroin, morphine, oxycodone, and hydrocodone.¹⁸

The severity of opioid withdrawal symptoms can vary, depending on factors such as the duration of use, typical dose taken, and dosing interval.²⁰ However, the following range of withdrawal symptoms may develop when any type of opioid drug is abruptly stopped:²⁰

Given this wide range of uncomfortable symptoms, opioid withdrawal is typically quite unpleasant, but it’s usually not life-threatening.²⁰ That said, medically assisted detox can help to ensure that patients are as safe and as comfortable as possible during withdrawal. As part of a supervised medical detox, opioid withdrawal management may include medications such as buprenorphine, methadone, or lofexidine.²¹

Codeine Drug Rehab Treatment

Codeine addiction (i.e., an opioid use disorder) can be treated via a host of options. Often individuals start with detox, but this is merely the first step in the treatment process. Following detox, patients often enter inpatient care, during which they live at a rehab facility where they receive 24/7 care and monitoring in a setting free of use-related triggers.²²

Outpatient  treatment is another option, which can follow either detox or inpatient care. With outpatient care, patients live at home while attending treatment, which varies in intensity. Options include traditional outpatient rehab, partial hospitalization programs (PHPs), intensive outpatient programs (IOPs), and telehealth services.²²

To assist in maintaining sobriety, many individuals enter aftercare programs following inpatient and/or outpatient care. Aftercare comprises solutions such as sober living facilities, ongoing therapy, 12-Step programs, and more.

With facilities scattered across the country, American Addiction Centers provides all levels of care via evidence-based treatment programs. Its rehab centers are equipped to treat a host of substance use disorders including those involving opioids such as codeine.

If you or a loved one is struggling with an opioid use disorder, AAC is here to help—and to listen to your unique story. Take the first step today by speaking with an admissions navigator at or by verifying your insurance benefits online. Available 24/7 for a free and confidential conversation, AAC staff can discuss payment options and treatment particulars and can help you begin your recovery today.