Ethanol is antidote for poisoning of –
**Core Concept**
Ethanol serves as an antidote in the management of poisoning with certain substances, particularly methanol and isopropanol. This is due to its ability to competitively inhibit alcohol dehydrogenase, the enzyme responsible for the initial metabolism of these toxic alcohols.
**Why the Correct Answer is Right**
Methanol and isopropanol are metabolized by alcohol dehydrogenase to their respective toxic metabolites, formaldehyde and acetone. Ethanol, being a competitive inhibitor of alcohol dehydrogenase, reduces the conversion of methanol and isopropanol to their toxic metabolites. This decreases the formation of formaldehyde and acetone, thereby reducing the severity of the poisoning. Ethanol also provides a substrate for the enzyme, allowing it to be saturated and thus reducing the metabolism of methanol and isopropanol.
**Why Each Wrong Option is Incorrect**
**Option A:** Ethanol is not an antidote for poisoning with other substances like salicylates (aspirin), barbiturates, or benzodiazepines, which require different treatment strategies.
**Option B:** Ethanol does not directly counteract the effects of opioid overdose, which is typically managed with naloxone.
**Option C:** Ethanol is not used as an antidote for poisoning with other alcohols like butanol or propanol, which may require different treatment approaches.
**Clinical Pearl / High-Yield Fact**
When managing a patient with suspected methanol or isopropanol poisoning, the administration of ethanol as an antidote should be accompanied by hemodialysis to remove the toxic metabolites from the body.
**Correct Answer: D.**