Pharmacology of ethanol
| Clinical data | |||
|---|---|---|---|
| Routes of administration | Common: By mouth Uncommon: suppository, inhalation, ophthalmic, insufflation, injection | ||
| Drug class | Analgesic; Anaphrodisiac; Anxiolytic; Depressant; Euphoriant; General anesthetic; Sedative | ||
| ATC code | |||
| Pharmacokinetic data | |||
| Bioavailability | 80%+ | ||
| Protein binding | Weakly or not at all | ||
| Metabolism | Liver (90%): • Alcohol dehydrogenase • MEOS (CYP2E1) | ||
| Metabolites | Acetaldehyde; Acetic acid; Acetyl-CoA; Carbon dioxide; Ethyl glucuronide; Ethyl sulfate; Water | ||
| Onset of action | Peak concentrations: • Range: 30–90 minutes • Mean: 45–60 minutes • Fasting: 30 minutes | ||
| Elimination half-life | Constant-rate elimination at typical concentrations: • Range: 10–34 mg/dL/hour • Mean (men): 15 mg/dL/hour • Mean (women): 18 mg/dL/hr At very high concentrations (t1/2): 4.0–4.5 hours | ||
| Duration of action | 6–16 hours (amount of time that levels are detectable) | ||
| Excretion | • Major: metabolism (into carbon dioxide and water) • Minor: urine, breath, sweat (5–10%) | ||
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| PDB ligand | |||
| Chemical and physical data | |||
| Formula | C2H6O | ||
| Molar mass | 46.069 g·mol−1 | ||
| 3D model (JSmol) | |||
| Density | 0.7893 g/cm3 (at 20 °C) | ||
| Melting point | −114.14 ± 0.03 °C (−173.45 ± 0.05 °F) | ||
| Boiling point | 78.24 ± 0.09 °C (172.83 ± 0.16 °F) | ||
| Solubility in water | Miscible mg/mL (20 °C) | ||
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The pharmacology of ethanol involves both pharmacodynamics (how it affects the body) and pharmacokinetics (how the body processes it). In the body, ethanol primarily affects the central nervous system, acting as a depressant and causing sedation, relaxation, and decreased anxiety. The complete list of mechanisms remains an area of research, but ethanol has been shown to affect ligand-gated ion channels, particularly the GABAA receptor.
After oral ingestion, ethanol is absorbed via the stomach and intestines into the bloodstream. Ethanol is highly water-soluble and diffuses passively throughout the entire body, including the brain. Soon after ingestion, it begins to be metabolized, 90% or more by the liver. One standard drink is sufficient to almost completely saturate the liver's capacity to metabolize alcohol. The main metabolite is acetaldehyde, a toxic carcinogen. Acetaldehyde is then further metabolized into ionic acetate by the enzyme aldehyde dehydrogenase (ALDH). Acetate is not carcinogenic and has low toxicity, but has been implicated in causing hangovers. Acetate is further broken down into carbon dioxide and water and eventually eliminated from the body through urine and breath. 5 to 10% of ethanol is excreted unchanged in the breath, urine, and sweat.