Conditions and symptoms
What Is G6PD Deficiency? Why Medicine Labels Mention It
G6PD deficiency · say it: jee-siks-pee-dee dih-FISH-un-seeAlso written: glucose-6-phosphate dehydrogenase deficiency, favism, G6PD
Short answer
G6PD deficiency is an inherited shortage of an enzyme that protects red blood cells, so some medicines, foods or infections can break them down.
What it means
G6PD is an enzyme that protects red blood cells from damage. In G6PD deficiency, which is inherited and more common in men, there is less of it. Most people have no symptoms day to day, but certain triggers, such as some medicines, fava beans, mothballs (naphthalene) or infections, can cause red cells to break down (hemolysis). Dark urine, yellow skin or eyes, or sudden tiredness and breathlessness after a trigger need urgent medical help.
Labels mention it because a number of medicines can trigger hemolysis in people with this condition, including primaquine and tafenoquine (antimalarials), dapsone, rasburicase, methylene blue and some sulfonamides and nitrofurantoin. Some labels require a G6PD blood test before the first dose. If you know you have it, tell every prescriber and pharmacist.
It is not an allergy. It is a lifelong enzyme difference, and the main way to stay well is to avoid known triggers.
Where you may see it
- 'Contraindications' and 'Warnings' sections of primaquine, tafenoquine, dapsone and rasburicase labels
- Blood test reports (G6PD screen)
- Newborn screening and haematology letters
📄 How it looks on a report
Contraindicated in patients with G6PD deficiency or unknown G6PD status.
🙅 What it does not mean
- It does not make every medicine unsuitable; only certain ones are triggers.
- It is not an allergy.
- Having no symptoms does not mean the condition has gone; triggers can still cause problems.
🗒️ Questions to ask your doctor
💊 Medicines whose labels mention “G6PD deficiency”
Plain-English explanations of each medicine, from its official FDA label.
- Glimepiride
a sulfonylurea, a type of oral medicine used to lower blood sugar in adults with type 2 diabetes
- Glipizide
a blood-sugar-lowering medicine of the sulfonylurea type
- Nitrofurantoin
an antibacterial medicine of the nitrofuran type, used for urinary tract infections
- Primaquine
An antimalarial medicine of the 8-aminoquinoline group, as described in the label
🔗 Read more from trusted sources
- “G6PD deficiency” on MedlinePlus ↗
US National Library of Medicine
- NCI Dictionary definition ↗
US National Cancer Institute: “g6pd deficiency”
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