Usage
- Medical Conditions: While not typically prescribed as a “drug,” alcohol (ethanol) has limited medical applications. It can be used as a disinfectant and antiseptic for cleaning wounds and sterilizing medical equipment. It is also sometimes used as a solvent in certain pharmaceutical preparations. Intravenous alcohol is occasionally used to treat methanol or ethylene glycol poisoning.
- Pharmacological Classification: Central nervous system depressant.
- Mechanism of Action: Ethanol enhances the effect of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) at the GABAA receptor, leading to widespread central nervous system depression. It also affects other neurotransmitter systems, such as dopamine and serotonin.
Alternate Names
- Ethanol, ethyl alcohol
- Brand names vary widely depending on the type of alcoholic beverage (e.g., beer, wine, spirits). There are no “pharmaceutical” brand names for pure ethanol intended for consumption.
How It Works
- Pharmacodynamics: Alcohol exerts its primary effect on the central nervous system, causing a dose-dependent depression that ranges from mild relaxation and euphoria at low doses to sedation, unconsciousness, and respiratory depression at high doses. It also affects other systems, such as the cardiovascular system (vasodilation, decreased myocardial contractility), gastrointestinal system (increased gastric acid secretion), and renal system (diuresis).
- Pharmacokinetics:
- Absorption: Rapidly absorbed from the gastrointestinal tract, with peak blood concentrations typically occurring within 30-90 minutes.
- Metabolism: Primarily metabolized in the liver by alcohol dehydrogenase to acetaldehyde, which is further metabolized to acetate by aldehyde dehydrogenase. A small amount is metabolized by the cytochrome P450 system (CYP2E1).
- Elimination: Mostly eliminated as carbon dioxide and water, with a small amount excreted unchanged in urine, sweat, and breath.
- Mode of Action: Ethanol binds to the GABAA receptor, increasing the receptor’s sensitivity to GABA, leading to enhanced chloride influx and neuronal hyperpolarization, thereby inhibiting neuronal activity. It also modulates other neurotransmitter systems and affects membrane fluidity.
- Elimination Pathways: Hepatic metabolism (primarily), renal excretion (minor), pulmonary excretion (minor).
Dosage
Dosage guidelines for medical use of alcohol are limited to its application as an antidote for certain poisonings (methanol, ethylene glycol). There are no standard dosage guidelines for recreational alcohol consumption for medical purposes.
Side Effects
Common Side Effects
- Nausea, vomiting
- Dizziness, headache
- Impaired coordination, slurred speech
- Loss of inhibitions
Rare but Serious Side Effects
- Respiratory depression
- Coma
- Liver damage
- Cardiac arrhythmias
Long-Term Effects
- Alcohol dependence
- Liver cirrhosis
- Wernicke-Korsakoff syndrome
- Increased risk of certain cancers
Adverse Drug Reactions (ADR)
- Anaphylaxis (rare, associated with certain alcoholic beverages)
- Severe intoxication leading to respiratory arrest
Contraindications
- History of alcohol dependence
- Severe liver disease
- Acute pancreatitis
- Pregnancy
- Concurrent use of certain medications (e.g., sedatives, opioids)
Drug Interactions
- Central Nervous System Depressants: Additive effects with other CNS depressants (e.g., benzodiazepines, opioids).
- Disulfiram: Causes a disulfiram-like reaction (flushing, headache, nausea, vomiting) when alcohol is consumed.
- Metronidazole: Similar disulfiram-like reaction.
- Oral Hypoglycemics: May potentiate hypoglycemia.
- Acetaminophen: Increased risk of liver damage with chronic alcohol use.
Pregnancy and Breastfeeding
- Pregnancy Safety Category: X (Contraindicated)
- Fetal Risks: Fetal alcohol spectrum disorders (FASDs), including growth retardation, facial abnormalities, and intellectual disability.
- Breastfeeding: Alcohol passes into breast milk and can affect the infant. Avoid alcohol consumption while breastfeeding.
Drug Profile Summary
- Mechanism of Action: Enhances GABA activity, leading to CNS depression.
- Side Effects: Nausea, vomiting, dizziness, impaired coordination, respiratory depression, coma.
- Contraindications: Alcohol dependence, liver disease, pancreatitis, pregnancy.
- Drug Interactions: CNS depressants, disulfiram, metronidazole.
- Pregnancy & Breastfeeding: Contraindicated in pregnancy; avoid during breastfeeding.
- Dosage: Limited medical use as an antidote. No standard dosage for recreational use.
- Monitoring Parameters: Blood alcohol concentration (BAC), vital signs, liver function tests.
Popular Combinations
There are no medically recommended combinations involving alcohol for consumption.
Precautions
- Avoid operating machinery or driving while under the influence of alcohol.
- Pre-existing medical conditions (e.g., liver disease, epilepsy) may require further caution.
- Alcohol should not be consumed during pregnancy.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Alcohol in methanol poisoning?
A: The dosage and administration of alcohol for methanol poisoning is complex and should be managed by experienced medical professionals. It involves achieving and maintaining a specific blood alcohol concentration (BAC) to inhibit methanol metabolism. Consult a toxicology specialist or poison control center for specific guidance.
A: Primarily metabolized in the liver by alcohol dehydrogenase to acetaldehyde, which is then metabolized by aldehyde dehydrogenase to acetate.
Q3: What are the signs of alcohol intoxication?
A: Slurred speech, impaired coordination, loss of inhibitions, nausea, vomiting, confusion, and at higher doses, respiratory depression and coma.
Q4: What are the long-term effects of chronic alcohol use?
A: Liver cirrhosis, alcoholic cardiomyopathy, Wernicke-Korsakoff syndrome, increased risk of certain cancers.
Q5: Can alcohol interact with other medications?
A: Yes, alcohol can interact with numerous medications, including CNS depressants, disulfiram, metronidazole, and others.
Q6: Is alcohol safe during pregnancy?
A: No, alcohol is contraindicated during pregnancy due to the risk of fetal alcohol spectrum disorders (FASDs).
Q7: How should alcohol poisoning be managed?
A: Supportive care, including airway management, oxygen therapy, intravenous fluids, and monitoring of vital signs. Specific antidotes may be used in cases of methanol or ethylene glycol poisoning.
Q8: What are the symptoms of alcohol withdrawal?
A: Tremors, anxiety, sweating, nausea, vomiting, seizures, and delirium tremens (DTs).
Q9: How is alcohol withdrawal treated?
A: Supportive care and benzodiazepines to manage withdrawal symptoms.
Q10: Can alcohol be used to clean wounds?
A: While alcohol has antiseptic properties, its use for wound cleaning is not generally recommended due to its potential to damage tissue. Other antiseptic solutions are preferred.
