Re: Why is methanol poisoning treated with large doses of ethanol?

I have included an answer provided by a madsci colleague regarding the 
lethality of methanol after my own answer. The reason you can treat methanol 
poisoning with ethanol is that ethanol acts as a competitive inhibitor.  
Ethanol is a competing substrate and so it blocks the conversion of methanol 
to its toxic products. Competitive inhibitors act by occupying the same site 
in the enzyme that the substrate occupies thus preventing the substrate from 
being acted upon by the enzyme. For a good discussion of enzymes and 
inhibitors you can read:

Stryer:Biochemistry, read the chapter on Introduction to Enzymes.

hope this helps
gabriel vargas md/phd



MadSci Network: Medicine 


Re: Why is methanol fatal? 

Area: Medicine 
Posted By: Kevin Reed, Engineer, None, 
Date: Fri Sep 19 20:03:47 1997
Area of science: Medicine 
ID: 874600966.Me 

Message:

                                         MadSci Network: Medicine 


Mahvish,

Methanol is an especially nasty type of alcohol because the body tries to 
break it down the same way it metabolizes, or breaks down, ethanol, the type 
of alcohol in beer, wine and
other drinks. Metabolizing ethanol produces chemicals less toxic to the body 
than alcohol. Unfortunately, if the same chemical action is performed on 
methanol the result is
formic acid, lactic acid and formaldehyde. 

Formaldehyde attacks nerve cells, especially the optic nerve and can damage 
the liver and kidneys. Formic acid and lactic acid also attack the kidneys 
and liver. Most people who
have drunk methanol die of severe and sudden kidney and liver failure.

More information on the clinical symptoms and treatment of methanol 
poisoning can be found at the South African Medicines Formulary at http://www.uct.ac.za/
depts/mmi/jmoodie/v03bhtml.html