Q: Why it is important to quickly reverse metabolic acidosis in methanol poisoning?


Answer: Ingested methanol is metabolized first to formaldehyde and then to formic acid. Treating acidosis with sodium bicarbonate in methanol poisoning converts formic acid to it anion form formate. Formate, unlike formic acid cannot penetrate and diffuse across cell membranes of end-organ tissues particularly retina, a major danger of methanol toxicity. 


Reference: 

Barceloux, D. G.; Bond, G. R.; Krenzelok, E. P.; Cooper, H; Vale, J. A.;  "American Academy of Clinical Toxicology practice guidelines on the treatment of methanol poisoning". Journal of toxicology. Clinical toxicology. 2002: 40 (4): 415–46.