![]() ![]() ![]() Most troubling though is getting the ethanol dose right. Ethanol is irritating to veins and has significant CNS effects. Using ethanol to treat methanol or ethylene glycol poisoning is problematic. Give a 15 mg/kg IV loading dose followed by 10 mg/kg every 12 hours until the blood pH is normal and serum alcohol concentration is less than 20 mg/dL. Two options are available for inhibiting alcohol dehydrogenase and the formation of toxic metabolites:įomepizole is highly effective, has few side effects, is simple to dose, but is expensive. Antidote treatment involves inhibiting alcohol dehydrogenase. If only supportive care is given toxic metabolites will continue to form. In the case of methanol the metabolites also lead to permanent blindness and in the case of ethylene glycol the metabolites also lead to acute kidney injury. However alcohol dehydrogenase converts these alcohols into highly toxic metabolites that lead to hypoxia and metabolic acidosis. Until they are metabolized, methanol and ethylene glycol cause sedation but are otherwise non-toxic. If there is any doubt about whether to end or extend treatment with N-acetylcysteine, I always consult with poison control by calling 1-80 from within the US. Shout out to Pharmacy Student Kaitlin who will be presenting on this topic in the near future! Regardless of which protocol is used, N-acetylcysteine treatment should be extended if the acetaminophen level remains elevated when N-acetylcysteine treatment is scheduled to end. Interestingly, the hepatic first-pass effect brings oral N-acetylcysteine directly to the desired site of action. ![]() IV administration does carry a risk of anaphylactoid reaction which is rarely serious. The IV protocol is attractive because it takes less time and avoids the unpleasant taste of oral N-acetylcysteine. Oral N-acetylcysteine has a particularly unpleasant smell & taste which can be masked by mixing with ice, cola, and drinking quickly through a straw. 70 mg/kg orally every four hours for a total of 17 doses. A loading dose of 140 mg/kg orally followed by:Ģ. The 72 hour oral N-acetylcysteine protocol involves:ġ. A loading dose of 150 mg/kg IV over 60 minutes followed by: The 20 hour protocol involves compounding three different bags of N-acetylcysteine for IV infusion:ġ. N-acetylcysteine can be given IV or orally using either a 20 hour or 72 hour protocol. If N-acetylcysteine is given within 10 hours of ingestion of toxic doses of acetaminophen, prognosis is excellent. The antidote for acetaminophen toxicity – N-acetylcysteine (NAC) – restores hepatic glutathione stores, allowing NAPQI to be safely neutralized and preventing hepatic damage. If only supportive care is given, NAPQI will continue to be formed and fulminant hepatic failure and death will ensue. Hepatic glutathione stores eventually deplete and NAPQI begins to damage hepatocytes. This toxic metabolite is readily and safely neutralized by hepatic glutathione before any damage to hepatocytes can occur.Īfter the administration of a toxic dose of acetaminophen (generally considered to be 7.5 g or more in adults), the safe metabolic pathways of sulfation and glucuronidation are saturated, and more of the toxic NAPQI is produced. About 8 % is metabolized via the hepatic cytochrome P450 pathway into the hepatotoxic metabolite N-acetyl-p-benzoquinoneimine (NAPQI). Two common examples are acetaminophen poisoning and methanol or ethylene glycol poisoning.Īt therapeutic doses, most acetaminophen is metabolized via sulfation and glucuronidation into safe metabolites and eliminated in the urine. Most medications, even when taken in overdose, will be safely cleared if a patient’s vital organ systems can be supported long enough.īut some overdose situations require an antidote in addition to supportive care for the the patient to survive. Supportive care is the mainstay of treatment for overdose patients. Compare that to the over 1500 medications that have been approved by the FDA and it is readily apparent that most medications do not have antidotes. Subscribe on iTunes, Android, or StitcherĪ special shout out to my kids for the artwork & audio bumper for this episode!Įxpert Consensus Guidelines for Stocking of Antidotes in Hospitals That Provide Emergency Care list just 21 antidotes to medications for stocking. In this episode I’ll focus on 2 examples of medication overdose that require more than supportive care to treat effectively: ![]()
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