This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
In methyl alcohol poisoning there is CNS depression, cardiac depression and optic nerve atrophy. These effects are produced due to ? 
Select and explain. 
A. Formaldehyde and formic acid, B. Acetaldehyde, C. Pyridine, D. Acetic acid
A: Formaldehyde and formic acid
Answer: A: Formaldehyde and formic acid 
Explanation: Ans. is 'a' i.e., Formaldyhyde and formic acid o Methyl alcohol (methanol) is metabolized to formaldehyde by alcohol dehydrogenase and then to formic acid by aldehyde dehydrogenase. These compounds are responsible for the toxicity. Formic acid can lead to coma and blindness also. Therefore, inhibitor of alcohol dehydrogenase, Femepizole is used for treatment of methanol over dose.