Acute methanol poisonings: Folates administration and visual sequelae

Abstract

During the outbreak of methanol poisonings in the Czech Republic 2012, we studied the clinical effectiveness of folate therapy in preventing visual damage. Data were obtained from a combined prospective and retrospective study on 79 patients: folinic acid was administered in 28, folic acid in 35; 16 patients received no folates. The groups were comparable by age, time to treatment, laboratory findings, symptoms, and treatment. The number of patients with visual sequelae differed neither between the groups treated with folinic/folic acid, nor between the groups with/without folate administration. The patients with visual sequelae were more acidotic and differed in pH, HCO3−, base deficit, anion gap, but not in methanol, ethanol, osmolal gap, formate, and pCO2. Serum lactate, but not formate differed significantly. The higher serum glucose on admission was in the patients with visual sequelae. Regardless the rationale for folate administration in acute methanol poisoning, its clinical effectiveness in preventing visual damage was not demonstrated in our study. The detoxifying effect of the pathway of tetrahydrofolate-mediated formate conversion is secondary to the formate elimination by haemodialysis. The results of our study cannot promote folinic acid as more efficient than folic acid, but also cannot discount the possible utility of adjunct folate therapy.