Ethanol
Ethanol (ethyl alcohol) is primarily used in veterinary medicine as an **antidote** for **ethylene glycol (antifreeze)** or **methanol** toxicity. - **Fomepizole (4-MP)** is generally the modern treatment of choice for ethylene glycol poisoning, but ethanol remains a readily available and economical alternative if the patient presents within a few hours of ingestion. - **Alternative uses**: Percutaneous injection of 95% ethanol has been used successfully to treat feline hyperthyroidism. Aerosolized ethanol has been used as a mucokinetic agent in horses. > **Clinical Pearl**: In emergency settings where pharmaceutical-grade ethanol is unavailable, commercial spirits (like vodka or grain alcohol/Everclear) are frequently compounded into IV fluids to create life-saving infusions.
กลไกการออกฤทธิ์: Ethanol acts by **competitively inhibiting the enzyme alcohol dehydrogenase**. - Ethylene glycol/Methanol + **Alcohol dehydrogenase** → Toxic metabolites (glycoaldehyde, glycolate, glyoxalate, and oxalic acid). - By occupying the enzyme, ethanol prevents this conversion, allowing the parent toxin (ethylene glycol or methanol) to be excreted primarily unchanged in the urine. - **Note**: For alcohol to be effective, it must be given very early after ingestion; it is seldom useful if started 8 hours after a significant ingestion.
ขนาดยาตามชนิดสัตว์
- Ethylene glycol poisoning · 5.5 mL/kg IV q4h for 5 treatments, then q6h for four additional treatments · IV · q4h then q6h · 9 treatments total · As a 20% solution; dosed as a CRI over 1 hour
- Ethylene glycol poisoning · 8.6 mL/kg slowly IV followed by a CRI of 1.43 mL/kg/hr · IV · CRI · at least 36 hours although 48 hours is probably better · Make a 7% ethanol solution. If EG test was positive initially, check before stopping treatment; discontinue if it reverts to negative.
- Ethylene glycol toxicity · 5.5 ml of 20% ethanol solution/kg · IV · q4h for 5 treatments, then q6h for 4 additional treatments · 9 treatments total · Adjust dose to maintain blood ethanol levels above 35 mg/dl.
- Ethylene glycol toxicity (CRI method) · Loading dose of 1.3 ml/kg of 30% solution, then 0.42 mg/kg/h · IV · CRI · 48 hours · Constant rate infusion method.
- Ethylene glycol toxicity (mild cases) · As directed (equivalent to IV dosing) · PO · As directed · Until toxicity resolves · For clinically mild cases with minimal CNS signs; vodka is often used.
- Ethylene glycol poisoning · 5 mL/kg IV q6h for 5 treatments, then q8h for four additional treatments · IV · q6h then q8h · 9 treatments total · As a 20% solution; dosed as a CRI over 1 hour
- Ethylene glycol poisoning · 8.6 mL/kg slowly IV followed by a CRI of 1.43 mL/kg/hr · IV · CRI · at least 36 hours although 48 hours is probably better · Make a 7% ethanol solution. If EG test was positive initially, check before stopping treatment; discontinue if it reverts to negative.
วิธีการให้ยา
ข้อห้ามใช้
- Concurrent use with fomepizole (usually contraindicated)
อาการไม่พึงประสงค์
- CNS depression
- Respiratory depression
- Diuresis
- Hypocalcemia
- Metabolic acidosis
- Pulmonary edema
- Injection site pain and infection
- Phlebitis
- Extravasation injury
- Bronchoconstriction and irritation (when aerosolized)
อันตรกิริยาระหว่างยา
- Bromocriptine · Alcohol may increase the severity of side effects seen with bromocriptine
- Activated Charcoal · Will inhibit absorption of orally administered ethanol; do not use if administering ethanol orally
- CNS Depressant Drugs (barbiturates, benzodiazepines, phenothiazines) · Alcohol may cause additive CNS depression
- Fomepizole (4-MP) · Inhibits alcohol dehydrogenase; ethanol metabolism is reduced significantly and alcohol poisoning (CNS depression, coma, death) can occur. Use together is generally not recommended.
- Insulin and antidiabetic drugs · Alcohol may affect glucose metabolism and the actions of insulin or oral antidiabetic agents
- Chlorpropamide, furazolidone, metronidazole · A disulfiram reaction (increased acetaldehyde with tachycardia, vomiting, weakness) may occur
- Fomepizole · Increases risk of severe alcohol toxicity; concurrent use should be avoided. · major
การติดตาม
- Alcohol blood levels (maintain at 100 to 130 mg/dL; safer to maintain >130 mg/dL than to fall below 100 mg/dL)
- Ethylene glycol or methanol levels
- Degree of CNS effect
- Fluid and electrolyte status
การได้รับยาเกินขนาด
If clinical signs of overdosage occur (**lateral nystagmus, respiratory depression, profound obtundation**), either slow the infusion or discontinue temporarily. Alcohol blood levels may be used to monitor both efficacy and toxicity of alcohol.
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