What happens when you take alcohol with codeine?
Codeine is an opioid analgesic that is itself relatively weak, but it is converted in the liver by the CYP2D6 enzyme to morphine, which is a far more potent opioid agonist. Approximately 10 percent of codeine is converted to morphine in most people, but there is wide genetic variation in CYP2D6 activity. Some people are poor metabolizers and get little analgesic effect from codeine, while others are ultra-rapid metabolizers who convert codeine to morphine very efficiently, producing higher blood concentrations from the same dose.
When alcohol is added to codeine, several dangerous things happen. Both substances are CNS depressants that act on the brainstem respiratory centers, slowing breathing rate and depth. The combined effect is greater than the sum of the parts. Alcohol enhances GABA activity while suppressing glutamate, and codeine's morphine metabolite activates mu-opioid receptors. Together, they can suppress respiration to the point of apnea, especially during sleep when respiratory drive is naturally reduced.
The CYP2D6 ultra-rapid metabolizer phenotype creates additional risk. Estimated to occur in 1 to 10 percent of various populations, with higher rates in some ethnic groups, this genetic variant causes rapid and excessive conversion of codeine to morphine. The FDA issued specific warnings about codeine use in nursing mothers who are ultra-rapid metabolizers because of infant deaths from morphine in breast milk, and contraindicated codeine use in children under 12 for similar reasons. For these individuals, even small amounts of alcohol combined with standard codeine doses can be lethal.
Beyond respiratory depression, the combination causes profound sedation, cognitive impairment, and motor coordination loss. Driving, operating machinery, or any activity requiring alertness becomes hazardous. The combination also increases nausea, vomiting, and constipation, and can cause hypotension and falls, particularly in older adults.
Why is this important?
Codeine has long been viewed as a relatively safe opioid because of its weakness compared to morphine or oxycodone, but this perception has led to underestimation of its risks. The genetic variability in CYP2D6 metabolism means that some people experience codeine effects that are similar to taking morphine directly. Combined with alcohol, the lethal dose range becomes substantially narrower.
The FDA prescribing information for codeine includes warnings about concomitant alcohol use, stating that the combination may result in additive central nervous system depression, respiratory depression, profound sedation, coma, and death. Codeine-containing products carry boxed warnings about respiratory depression, accidental overdose, and ultra-rapid metabolizer risk.
Codeine is often used in liquid formulations for cough suppression, including some prescription cough syrups. Liquid formulations can be easier to overdose on inadvertently, and they are sometimes consumed in larger quantities than intended for the cough indication. Mixing such products with alcohol, particularly in recreational use patterns like "lean" or "purple drank" which combines codeine cough syrup with alcohol or soda, has caused numerous deaths, particularly among young adults.
Certain populations face especially elevated risk. CYP2D6 ultra-rapid metabolizers may not know their status, and there is no routine testing before codeine prescribing. Older adults have reduced respiratory reserve and altered drug metabolism. People with sleep apnea, COPD, asthma, or other respiratory conditions have less margin for error. Those taking other CNS depressants, including benzodiazepines, sleep aids, muscle relaxants, gabapentin, or sedating antihistamines, face cumulative risk.
What should you do?
If you have been prescribed codeine, abstain completely from alcohol throughout the treatment period. Codeine has a half-life of about 3 hours, but its effects can persist longer in some individuals and the active morphine metabolite has its own duration of action. Wait at least 24 hours after your last codeine dose before consuming any alcohol.
This includes codeine in any form: tablets for pain, liquid cough syrups, combination products with acetaminophen (Tylenol with Codeine, Tylenol #3, Tylenol #4), or combination products with promethazine for cough. Many people do not think of cough syrups as serious medications and may mix them with alcohol without considering the interaction. This is dangerous and has caused fatalities.
If you are taking codeine for acute pain after surgery or injury, plan for an alcohol-free period throughout the prescription. If you have been prescribed codeine for chronic cough or pain, alcohol abstinence should continue throughout treatment. Hiding alcohol use from your prescriber prevents accurate risk assessment.
Read labels carefully on combination products. Many cough syrups contain codeine alongside other ingredients, sometimes including alcohol in the syrup base itself. If a cough syrup contains codeine and you drink any alcoholic beverages, you are combining the substances even without intending to. Watch for warning signs that require emergency medical attention: excessive drowsiness or inability to wake, slow or shallow breathing, blue lips or fingertips, pinpoint pupils, confusion, or unresponsiveness. Call 911 immediately and administer naloxone if available.
Which specific products are affected?
Codeine is available in many forms. Tablets contain codeine alone or in combination with acetaminophen (Tylenol with Codeine, often labeled #2, #3, or #4 based on codeine dose) or aspirin. Many countries previously sold codeine with acetaminophen over the counter, though this has been restricted in recent years due to safety concerns. Liquid codeine preparations are most often cough syrups, including codeine-promethazine combinations (Phenergan with Codeine) and codeine-guaifenesin combinations.
Specific brand names include but are not limited to: Tylenol with Codeine, Codeine Contin (extended-release codeine), Solpadeine, Co-codamol, Empirin with Codeine, and many international formulations. Promethazine with codeine cough syrup has been a significant target of recreational abuse, leading to several manufacturers discontinuing the product. Pseudoephedrine-codeine-guaifenesin combinations also exist.
The combination products that include acetaminophen pose additional risk because alcohol increases acetaminophen hepatotoxicity. Tylenol #3 (acetaminophen 300 mg with codeine 30 mg) is among the most commonly prescribed combinations, and combining it with regular alcohol use creates both respiratory depression risk and liver toxicity risk simultaneously.
On the alcohol side, the warning applies to all ethanol sources: beer, wine, spirits, liqueurs, alcohol in liquid medications (including some cough syrups, ironically, that contain alcohol as a solvent), herbal tinctures, mouthwash if swallowed, hand sanitizer if ingested, and cooking alcohol that has not fully evaporated. Even small amounts contribute to the interaction.
The bottom line
Codeine combined with alcohol is a dangerous combination that can cause fatal respiratory depression, with risk amplified for the substantial minority of people who are CYP2D6 ultra-rapid metabolizers. The FDA prescribing information warns clearly against the combination. The risk applies to all codeine-containing products, including the cough syrups that many people may not consider serious medications. If you are prescribed codeine in any form, abstain from alcohol throughout treatment and for at least 24 hours after the last dose. Read combination product labels carefully, and never mix codeine cough syrups with alcohol recreationally. This combination has caused many preventable deaths.