Codeine Stats & Data

1) Codeine’s potency is highly variable due to CYP2D6 genetics: ultrarapid metabolizers convert more codeine to morphine and can experience life‑threatening respiratory depression at ‘normal’ doses, while poor metabolizers may feel little effect; start low, avoid dose-stacking, and be especially cautious if you or relatives have had unusual reactions to codeine or tramadol. Breastfeeding parents who are ultrarapid metabolizers have caused fatal infant opioid toxicity; avoid codeine if pregnant or breastfeeding. (NCBI Medical Genetics Summaries – Codeine/CYP2D6.) 2) Schedule V codeine cough syrups are limited to ≤200 mg/100 mL (≤2 mg/mL), and common promethazine/codeine products are 10 mg codeine + 6.25 mg promethazine per 5 mL; translate culture ‘pour’ sizes into milligrams to reduce accidental overdosing: 1 oz (30 mL) ≈ 60 mg codeine; 2 oz ≈ 120 mg; 3 oz ≈ 180 mg. (NCBI Medical Genetics Summaries; Drugs‑Forum community dosing labels; multiple Reddit threads corroborating 10 mg/5 mL.) 3) Promethazine is a strong CNS depressant with anticholinergic and antidopaminergic effects; it adds to opioid sedation and can cause confusion, disorientation, urinary retention, constipation, blurred vision, and (rarely) dystonia or seizures. Its long half‑life (∼10–19 h) means ‘hangover’ drowsiness and impairment can last into the next day—do not drive or operate machinery. (NCBI StatPearls – Promethazine.) 4) Combining any opioid (including codeine) with benzodiazepines, alcohol, gabapentinoids, Z‑drugs, barbiturates, or GHB markedly increases risk of fatal respiratory depression; promethazine further intensifies sedation. If polydrug use has occurred and breathing is slow or shallow, call emergency services and administer naloxone if available—be aware promethazine sedation may persist after naloxone reverses the opioid component. (TripSit combo guidance; DrugWise overdose harm‑reduction.) 5) Avoid stacking additional first‑generation antihistamines (e.g., diphenhydramine/doxylamine): they are also CNS depressants and diphenhydramine inhibits CYP2D6, which can unpredictably blunt euphoria yet increase sedation and risk. (TripSit codeine page.) 6) Some prescriptions are ‘VC’ formulations that include a decongestant (often phenylephrine); these can raise blood pressure and heart rate and are poor candidates for recreational dosing—always read the exact label. (Drugs‑Forum community threads discussing Phenergan VC with Codeine.) 7) Counterfeit or ‘homebrew’ lean may contain unknown opioids, benzodiazepines, or other sedatives; effects can mimic genuine products but potency and contents are unpredictable. Use only clearly labeled pharmacy products; if exposed to unknown syrups, start with very small test doses and avoid any other depressants. (Numerous community reports on Reddit lean forums.) 8) Never inject codeine syrups or attempt to filter for injection: codeine IV can cause pulmonary edema and severe reactions, and syrups contain excipients unsafe for injection. (Erowid Opioid FAQ.) 9) Opioids slow gut motility—constipation, nausea, and urinary retention are common; hydration, fiber, and planned bowel regimens reduce harm. Seek medical help for severe abdominal pain or no bowel movement for several days. 10) People with sleep apnea, chronic lung disease, obesity hypoventilation, or the very young/elderly are at higher risk of respiratory depression; promethazine carries a boxed warning for fatal respiratory depression in children under two—avoid in children and use extreme caution in adolescents. (NCBI StatPearls – Promethazine; NCBI Medical Genetics Summaries – Codeine.)