Hemodialysis in acute methanol poisoning: is there really good evidence?

February 16, 2015, 11:11 pm


Recommendations for the Role of Extracorporeal Treatments in the Management of Acute Methanol Poisoning: A Systematic Review and Consensus Statement. Roberts DM et al. Crit Care Med 2015 Feb;43:461-472.


The Extracorporeal Treatment in Poisoning (EXTRIP) Workgroup was established to provide evidence-based guidance on the use of hemodialysis and other methods of extracorporeal treatment in various toxic exposures. The workgroup has published previous papers giving their recommendations regarding poisoning by acetaminophen, lithium, carbamazepine, barbiturate, tricyclic antidepressants, and thallium.

This is a tremendously ambitious project, involving experts from many fields of medicine and pharmacology, and extensive review of the literature. Unfortunately, for many of these intoxications, good evidence simply does not exist. In this instance, all of the major  recommendations regarding methanol are rated as 1D. The rating of “1” indicates a “strong recommendation.” A level of evidence rated “D” is described in the paper thusly: “very low level of evidence (our estimate of the effect is just a guess, and it is very likely that the true effect is substantially different from our estimate of the effect.)”

That last statement is refreshingly honest. I’ve disagreed with some members of the workgroup in the past about this, but I still believe you can’t make real evidence-based recommendations on the basis of poor evidence. Rather than the word “guess,” I’d say that these recommendations are opinions. But given the extensive toxicology experience of members of EXTRIP, it is essential to engage with these consensus opinions. In addition, there is a wealth of pharmacologic and toxicologic information about methanol toxicity in this paper, and I’d consider it a must read.

For the record, here are the major recommendations in the paper:

Extracorporeal Treatment in a Patient with Methanol Poison is Recommended in the Following Circumstances:

1) Severe toxicity, including any of:

     a) coma

    b) seizures

    c) new visual deficits

    d) metabolic acidosis (pH < 7.15 or persistent acidosis despite supportive treatment)

    e) anion gap > 24 mmol/L

2) Serum methanol concentration

a)  > 70 mg/dL in context of fomepizole therapy

b)   > 60 mg/dL in context of ethanol treatment

c)  > 50 mg/dL in absence of alcohol dehydrogenase blocker therapy

3)  impaired kidney function (for definition, see supplement)


Again, all of these are 1D recommendations. Make of that what you will.

Related posts:

Hemodialysis in lithium poisoning: what is the evidence?

Must-read: consider hemodialysis in cases of massive acetaminophen overdose

What enhanced elimination techniques are useful in critical toxicology patients?

Hemodialysis and other extracorporeal modalities in toxicology cases




  1. Marc Ghannoum Says:


    I thoroughly enjoy reading your reviews. Thank you for addressing some of our EXTRIP papers. We encourage debate and discussion, if only to gather expertise and interest in treating these complicated patients.

    I mostly agree with your comments. Guidelines, or rather recommendations, need to remain fairly simple for most physicians to apply them. The variability of clinical scenarios and available resources preclude listing exhaustive indications; these would overwhelm most clinicians needing simple guidance on what to do when the clock is ticking. The window of opportunity is relatively short for dialysis in many poisons.

    Although we’ve listed systematically the complications associated with ECTR in included reports, dialytic procedures in 2015 are considered overwhelmingly safe and fairly inexpensive; our preliminary cost data shows that usually these procedures cost at most 2000$ in North America (excluding transfer if required), a lot less than 1 day in any ICU.

    I do disagree with the assertion that strong recommendations should not be presented in the absence of good evidence. if I gather 100 expert toxicologists and more than 75% of them strongly support a statement (example: fab in serious digoxin toxicity) regardless of the evidence underlying the statement, this is something that has value for those that have not reviewed the literature and who may be inexperienced with these patients. Hoping for strong evidence to justify a strong recommendation implies de facto designing a study with a control group. Unfortunately, these will likely never see the day, and considering the strong mechanistic rationale for dialysis in some indications, I would argue that they should not be even considered ethically. Otherwise, every specific EXTRIP recommendation is open for challenge and debate. But we shouldn’t, in my humble opinion, let the absence of good evidence solely restrict the publication of recommendations.

  2. Leon Says:


    Thank you very much for your comments. I completely agree with you that lack of good evidence does not preclude making recommendations regarding treatment for patients who may need dialysis. I have found the EXTRIP papers extremely valuable both for the discussion of individual poisons and for the workgroup’s thoughts about specific indications. There are, however, two factors that give me pause:

    1) Without good (or even fair) evidence, it can’t really be claimed that the recommendations are evidence-based. They are really based on the consensus opinions of the workgroup. Fortunately, since the workgroup consists of very smart and experienced clinicians, for me these opinions carry considerable weight. it is clear from some of the passages I quoted in my review that the EXTrIP workgroup is upfront about this, but the point may be missed on the casual reader who just looks at the abstract or the recommendations themselves.

    2) In some of the papers, extracorporeal treatment (basically hemodialysis) is looked at in isolation, without much reference to other therapeutic options. This struck me especially in the paper about lithium, where benefits of hemodialysis in some mildly intoxicated patients are unclear and other options (such as hydration and careful observation) may be preferable to immediate extracorporeal treatment.

    In any case, I have enjoyed all the EXTRIP papers and learned much from reading them. I eagerly look forward to future publications from the workgroup on poisons such as ethylene glycol.