Three Part Question
In [an adult with methanol/ethylene glycol poisoning] is [the addition of IV Calcium folinate better than ethanol alone] at [reducing the incidence of reduced acuity and retinal oedema)]?
A man attends the emergency department having deliberately taken 150 ml of "antifreeze". The can of antifreeze has conveniently been brought along and you find it consists of a mixture of methanol and ethylene glycol. The Poisons Centre is contacted. In addition to treatment with ethanol it is suggested that intravenous Leucovorin (calcium folinate) is given. You wonder if there is any evidence to support this recommendation.
Medline 1996-06/03 using the OVID interface.
[exp leucovorin OR folinic acid.mp OR Calcium folinate.mp] AND [exp methanol OR methanol.mp OR exp ethylene glycol OR ethylene glycol.mp OR antifreeze.mp] LIMIT to English.
Altogether 12 papers were found, none of which were relevant to humans. One paper published in two different journals described studies on monkeys and suggested that the results could be extrapolated to humans.
|Author, date and country
||Study type (level of evidence)
|Noker PE & Telphy TR,|
Effects of 5-fTHF or sodium folate following methanol poisoning are assessed||Experimental study||Metabolic acidosis||Did not develop in treated monkeys|
|Serum formate level||Lower than untreated monkeys: (p<0.05)|
In humans methanol toxicity is characterised by a metabolic acidosis and an ocular toxicity that occur coincident with an accumulation of formate in blood. After experimental studies on monkeys, Noker and Tephly hypothesised that folate compounds could decrease formate accumulation after methanol by stimulating formate oxidation or utilisation and suggested a possible use for folates in the treatment of certain cases of human methanol poisoning.
Clinical Bottom Line
There is no direct evidence of the usefulness of folates in methanol poisoning in humans. Local policy should be followed.
Level of Evidence
Level 3 - Small numbers of small studies or great heterogeneity or very different population.
- Noker PE, Tephly TR. The role of folates in methanol toxicity. Adv Exp Med Biol 1980;132:305-15.