Codeine

Standard Drug Panel Inclusion

Codeine is a natural or semi-synthetic opiate that is detected on standard 5-panel drug screens under the opiates channel. The standard opiate immunoassay targets morphine and codeine as primary analytes, and Codeine or its metabolites will trigger a positive result due to structural similarity to the morphine backbone. Most workplace, clinical, and probation drug tests include opiate detection at a 2000 ng/mL or 300 ng/mL cutoff.

Urine Detection

Codeine can be detected in urine for approximately 2 to 3 days after the last dose. The primary metabolic pathways involve glucuronidation, O-demethylation, and N-demethylation. Key urinary metabolites include glucuronide conjugates and, depending on the specific compound, morphine or hydromorphone as downstream metabolites. Hydration status, urinary pH, body mass, and metabolic rate all influence the exact detection window.

Blood and Saliva Detection

Codeine is detectable in blood for approximately 6 to 24 hours after administration. Oral fluid (saliva) testing can detect Codeine for approximately 24 to 48 hours post-dose. Blood and oral fluid testing are most commonly used in emergency medicine, pain management compliance monitoring, and roadside testing programs.

Hair Follicle Detection

Hair follicle testing can detect Codeine for up to 90 days (approximately 1.5 inches of hair growth). Opiate incorporation into hair is well-characterized, and most commercial hair testing panels include the opiates category. A standard hair test screens for codeine, morphine, and 6-monoacetylmorphine; Codeine or its metabolites will typically be captured under this panel.

Confirmatory Testing

Immunoassay screening results for opiates are confirmed using gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-tandem mass spectrometry (LC-MS/MS). These methods can distinguish between specific opiates, identifying Codeine and its metabolites with high specificity. Confirmation testing eliminates false positives from poppy seed consumption or structural analogues.

Reagent Testing

Marquis reagent produces a purple to violet color with Codeine, consistent with the morphine-class opiate reaction. Mecke reagent yields a deep blue-green to blue color. Mandelin reagent produces a grey-brown reaction. These reagent responses are characteristic of the opiate class and can help differentiate opiates from synthetic opioids, which may show different or no reactions.

General Principles

• Start low, go slow: Always begin with a low dose, especially with unfamiliar batches or new substances. Individual sensitivity varies enormously.
• Test your substances: Use reagent test kits to verify identity and check for dangerous adulterants. Consider using drug checking services where available.
• Research thoroughly: Understand expected dose ranges, duration, potential interactions, and contraindications before use.
• Never use alone: Have a trusted, sober person present, especially with new substances or higher doses.
• Set and setting: Your mindset and environment profoundly influence the experience. Choose a safe, comfortable environment and ensure you're in a stable psychological state.

Codeine-Specific Harm Reduction

• Naloxone: Always have naloxone (Narcan) available and ensure someone present knows how to use it. Naloxone reverses opioid overdose and can be life-saving.
• Never use alone: If you must use alone, call a never-use-alone helpline or use an app that will alert emergency services if you don't check in.
• Fentanyl awareness: Illicit drug supplies are widely contaminated with fentanyl and its analogues. Test every batch with fentanyl test strips, though be aware that test strips cannot detect every analogue and a negative result doesn't guarantee safety.
• Start very low: Tolerance drops rapidly with abstinence. If you've had a break from use (even a few days), your previous dose may now be lethal. Start at a fraction of your former dose.
• Respiratory depression: The primary cause of opioid death. Never combine with benzodiazepines, alcohol, or other depressants. Avoid using when overly tired.
• Recovery position: If someone appears sedated, place them in the recovery position (on their side) to prevent aspiration if they vomit.

Codeine has a low toxicity relative to dose. As with all opioids, long-term effects can vary but can include diminished libido, apathy and memory loss. Some people may also have an allergic reaction to codeine, such as the swelling of skin and rashes. It is also potentially lethal when mixed with depressants like alcohol or benzodiazepines.

It is strongly recommended that one use harm reduction practices when using this drug.

Tolerance and addiction potential

As with other opioids, the chronic use of codeine can be considered moderately addictive with a high potential for abuse and is capable of causing psychological dependence among certain users. When addiction has developed, cravings and withdrawal symptoms may occur if a person suddenly stops their usage.

Tolerance to many of the effects of codeine develops with prolonged and repeated use. The rate at which this occurs develops at different rates for different effects, with tolerance to the constipation-inducing effects developing particularly slowly for instance. This results in users having to administer increasingly large doses to achieve the same effects. After that, it takes about 3 - 7 days for the tolerance to be reduced to half and 1 - 2 weeks to be back at baseline (in the absence of further consumption). Codeine presents cross-tolerance with all other opioids, meaning that after the consumption of codeine all opioids will have a reduced effect.

Dangerous interactions

Warning: Many psychoactive substances that are reasonably safe to use on their own can suddenly become dangerous and even life-threatening when combined with certain other substances. The following list provides some known dangerous interactions (although it is not guaranteed to include all of them).

Always conduct independent research (e.g. Google, DuckDuckGo, PubMed) to ensure that a combination of two or more substances is safe to consume. Some of the listed interactions have been sourced from TripSit.

• Alcohol - Both substances potentiate the ataxia and sedation caused by the other and can lead to unexpected loss of consciousness at high doses. Place affected patients in the recovery position to prevent vomit aspiration from excess. Memory blackouts are likely

• Stimulants - Stimulants increase respiration rate which allows for a higher dose of opiates than would otherwise be used. If the stimulant wears off first then the opiate may overcome the user and cause respiratory arrest.

• Benzodiazepines - Central nervous system and/or respiratory-depressant effects may be additively or synergistically present. The two substances potentiate each other strongly and unpredictably, very rapidly leading to unconsciousness. While unconscious, vomit aspiration is a risk if not placed in the recovery position blackouts/memory loss likely.

• DXM - Generally considered to be toxic. CNS depression, difficulty breathing, heart issues, and liver toxicity have been observed. Additionally if one takes DXM, their tolerance of opiates goes down slightly, thus causing additional synergistic effects.

• GHB/GBL - The two substances potentiate each other strongly and unpredictably, very rapidly leading to unconsciousness. While unconscious, vomit aspiration is a risk if not placed in the recovery position

• Ketamine - Both substances bring a risk of vomiting and unconsciousness. If the user falls unconscious while under the influence there is a severe risk of vomit aspiration if they are not placed in the recovery position.

• MAOIs - Coadministration of monoamine oxidase inhibitors (MAOIs) with certain opioids has been associated with rare reports of severe adverse reactions. There appear to be two types of interaction, an excitatory and a depressive one. Symptoms of the excitatory reaction may include agitation, headache, diaphoresis, hyperpyrexia, flushing, shivering, myoclonus, rigidity, tremor, diarrhea, hypertension, tachycardia, seizures, and coma. Death has occurred in some cases.

• MXE - MXE can potentiate the effects of opioids but also increases the risk of respiratory depression and organ toxicity.

• Nitrous - Both substances potentiate the ataxia and sedation caused by the other and can lead to unexpected loss of consciousness at high doses. While unconscious, vomit aspiration is a risk if not placed in the recovery position. Memory blackouts are common.

• PCP - PCP may reduce opioid tolerance, increasing the risk of overdose.

• Tramadol - Increased risk of seizures. Tramadol itself is known to induce seizures and it may have additive effects on seizure threshold with other opioids. Central nervous system- and/or respiratory-depressant effects may be additively or synergistically present.

• Grapefruit - While grapefruit is not psychoactive, it may affect the metabolism of certain opioids. Tramadol, oxycodone, and fentanyl are all primarily metabolized by the enzyme CYP3A4, which is potently inhibited by grapefruit juice. This may cause the drug to take longer to clear from the body. it may increase toxicity with repeated doses. Methadone may also be affected. Codeine and hydrocodone are metabolized by CYP2D6. People who are on medicines that inhibit CYP2D6, or that lack the enzyme due to a genetic mutation will not respond to codeine as it can not be metabolized into its active product: morphine.

Codeine is internationally controlled under Schedule II of the Single Convention on Narcotic Drugs (1961), though its legal status varies significantly by country and formulation.

• United States: Codeine's scheduling depends on its formulation. Pure codeine is aSchedule II controlled substance under the Controlled Substances Act (CSA). Combination products containing codeine with aspirin or acetaminophen are classified asSchedule III. Codeine-containing cough suppressants may be classified asSchedule III or Schedule V depending on concentration, and in some states, low-dose codeine cough syrups can be dispensed without a prescription (though pharmacist intervention is typically required).
• United Kingdom: Codeine is aClass B controlled substance under the Misuse of Drugs Act 1971 (elevated toClass A when prepared for injection). However, an important exemption exists underSchedule 5: preparations containing no more than 100mg of codeine per dosage unit can be sold over the counter at pharmacies without a prescription. Common OTC products include co-codamol (codeine + paracetamol) at the 8/500 strength.
• Australia: Pure codeine is aSchedule 8 (controlled drug) substance. Combination products areSchedule 4 (prescription only). In a significant regulatory shift,Australia moved all codeine-containing products to prescription-only status in February 2018, ending decades of over-the-counter availability. This change was driven by concerns over codeine dependence and accidental paracetamol toxicity from combination products.
• Canada: Codeine-containing products with up to8mg per dosage unit can be sold without a prescription when combined with at least two other active non-narcotic medicinal ingredients (e.g., Tylenol No. 1). Higher-strength formulations require a prescription. Pure codeine is a Schedule I narcotic under the Controlled Drugs and Substances Act.
• France: Codeine was reclassified asprescription-only in July 2017, following several deaths linked to recreational use of codeine cough syrups ("purple drank"). Previously, low-dose codeine preparations were available OTC.
• Germany: Codeine is regulated under the Betaubungsmittelgesetz (BtMG). It is available by prescription, though certain low-dose preparations are exempt from narcotic prescription requirements.
• Japan: Codeine is available by prescription only. Products containing codeine were restricted for patients under 12 years old starting in 2019.
• India: Codeine-containing cough syrups are prescription-only (Schedule H), though enforcement varies and misuse of codeine syrups remains a significant public health concern in some states.