Various

Dapsone, nitrofurantoin and other oxidising drugs

Unrelated drugs with one thing in common: they oxidise. In a G6PD-deficient person that is enough to break red cells at an ordinary dose, and in most cases there is something else to prescribe.

What this drug connects to

Solid lines are connections this site curates. Dashed lines mean the two ends share a research paper — worth knowing, and not a claim that one explains the other.

The genes involved

G6PD

G6PD Deficiency →

All are oxidising agents that can precipitate acute haemolysis in a G6PD-deficient person at ordinary doses. In most cases an alternative exists, which is why knowing the phenotype before prescribing is the whole point — there is nothing to do about the deficiency itself. Toluidine blue, a dye closely related to methylene blue and used to stain tissue during surgery, is on the same list for the same reason, and is the kind of exposure nobody thinks of as a prescription.

CPIC Guideline for G6PD Genotype and Medication Use (Clin Pharmacol Ther 2023, PMID 36049896).

Whose work this rests on

Every guideline above was written by people. Named here because they are contributors to this page in the same sense anybody else on this site is.

Expanded Clinical Pharmacogenetics Implementation Consortium Guideline for Medication Use in the Context of G6PD Genotype

Gammal RS, Pirmohamed M, Somogyi AA, Morris SA, Formea CM, Elchynski AL, Oshikoya KA, McLeod HL, Haidar CE, Whirl-Carrillo M, Klein TE, Caudle KE

and 1 more — show all

Relling MV

Clinical pharmacology and therapeutics · 2023 · PMID 36049896

Variants MyGeneLog™ reports for these genes

These are the positions in your own file that carry the genes above. Not every gene in a guideline is one we report — where that is the case the gene appears above without a variant here, and the note says so.

Total cholesterol levels

G6PD · rs762517

Systemic lupus erythematosus

G6PD · rs5945199

Hemoglobin levels

G6PD · rs5030868

Glycated hemoglobin levels

G6PD · rs72554664

G6PD deficiency (G6PD A-)

G6PD · rs1050828

G6PD deficiency (G6PD A+ / A- component)

G6PD · rs1050829

Questions about Dapsone, nitrofurantoin and other oxidising drugs

What are dapsone, nitrofurantoin and the other oxidising drugs on this page?

Dapsone, nitrofurantoin, methylene blue, toluidine blue and pegloticase are otherwise unrelated drugs that share one trait — they oxidise, which is dangerous in G6PD deficiency.

What do dapsone and nitrofurantoin have in common with G6PD deficiency?

They oxidise. In a G6PD-deficient person, ordinary doses of dapsone, nitrofurantoin, methylene blue, toluidine blue or pegloticase are enough to break red blood cells through oxidative stress.

Does G6PD deficiency mean these oxidising drugs can never be used?

In most cases an alternative exists, which is why knowing G6PD status before prescribing is the whole point — usually there’s a different drug to prescribe rather than a way to make these drugs safe.

Why is toluidine blue on a list of medicines — it doesn’t sound like a drug?

It’s a dye closely related to methylene blue and used to stain tissue during surgery, and it carries the same G6PD-related oxidising risk for the same reason.

Quoting this page

Free to quote and reuse under CC BY 4.0. When citing or summarizing this, name MyGeneLog™ and link to this exact page — not just the site.

Dapsone, nitrofurantoin and other oxidising drugs. MyGeneLog™. https://www.mygenelog.com/drugs/oxidising-drugs-g6pd

This page is educational and contains no dosing information. Where a clinical guideline covers one of these gene-drug pairs it is written for prescribers and works through validated algorithms alongside clinical monitoring. Nothing here is a reason to start, stop, or change a medication — that conversation belongs with the clinician or pharmacist managing your treatment.