Management of Ethanol and Methanol Poisoning

THE GUIDELINES FOR MANAGEMENT OF ETHANOL, METHANOL AND ETHYLENE GLYCOL POISONING AT THE EMERGENCY ROOM By Niru Prasad, M.D., F.A.A.P., F.A.C.E.P. Department of Emergency Medicine Henry Ford Hospital West Bloomfield Center Department of Ambulatory Pediatrics St. Joseph Mercy Hospital Pontiac Ethanol Overdose Introduction Pharmacokinetics Absorption and Metabolism Clinical Symptoms Produced by Ethanol Overdose Diagnosis, Laboratory Analysis and Treatment Ethanol is the most commonly abused drug in the United States, with approximately 10 percent of the adult population qualifying as alcoholics. Approximately 40 percent of the medical hospital admissions are related to ethanol abuse and multisystem organ dysfunctions secondary to chronic alcohol intake. The chronic alcohol intake can lead to numerous metabolic complications such as hypoglycemia, ketoacidosis, electrolyte disorders, neurologic disorders, withdrawal seizures, delirium tremens, gastritis, hepatitis, pancreatitis, as well as hematologic disorders. It is very important for the emergency physicians to recognize these patients. The adolescents and young adult suicide rates are frequently associated with ethanol abuse and overdose. It is also important to remember that the depressed level of consciousness in alcoholics could also be due to subdural hematoma, meningitis, and other central nervous systems lesions. Alcohol abuse is often associated with suicide,homicide, drowning, physical abuse, and motor vehicle accidents. The forms of alcohols are: Ethyl alcohol (ethanol) Ethylene glycol Isopropyl alcohol (isopropanol) Methyl alcohol Propylene glycol Diethylene glycol All of these forms of alcohol are low molecular weight, water soluble substances with prominent multiorgan toxicity. Pharmacokinetics of Ethanol Ethanol is absorbed in an unaltered state from the stomach and small intestine, metabolized by the liver and excreted through the kidneys. It has been recently postulated that the presence of alcoholic dehydrogenase in gastric mucosa degrades some of the absorbed ethanol, and histamine H-2 antagonist inhibits alcohol dehydrogenase hence patients taking acid suppressing drugs are more prone to alcohol toxicity with ethanol intake. Several hepatic enzymes convert ethanol to acetaldehyde. These enzymes are cytoplasmic alcohol dehydrogenase, catalase, and a microsomal ethanol oxidizing system. Metabolism of Ethanol Ethanol ̄ (alcohol dehydrogenase) Acetaldehyde ̄ (alcohol dehydrogenase) Acetic acid ̄ (Kreb's cycle) ̄ Carbon dioxide and water The alcohol dehydrogenase pathway is the predominant system for alcohol metabolism. The second pathway is the microsomal ethanol oxidizing system located in the endoplasmic reticulum. This system may be associated with cytochrome P-450 mixed function oxidase system in the liver. The third system involves the catalase located in the prioxisomes. The rate of metabolism of ethanol is in the rage of 15 to 25 milligrams per deciliter per hour. 12 mg/dl/hour in nondrinkers 15 mg/dl/hour in social drinkers 30 mg/dl/hour in alcoholics A 150 pound person metabolizes 10 ounces of beer in one hour. Effects Produced by Ethanol Metabolism 1. Drug Interactions 2. Carbohydrate Metabolism A. Hypoglycemia in the presence of inadequate food intake. B.