Why does G6PD deficiency cause dark urine?

Dark Urine is a common presentation of G6PD Deficiency. G6PD is an enzyme that helps red blood cells handle oxidative stress. During an episode of haemolysis, red cells break down faster than the body can replace them. Haemoglobin released from the cells may be filtered by the kidneys, making urine tea-coloured, brown or unusually dark.

An episode may follow an infection, certain medicines, exposure to chemicals, or foods that trigger haemolysis in a person with G6PD deficiency. Dark urine also has many other causes, including dehydration, bleeding and liver problems, so the colour alone cannot establish the cause.

If you have known G6PD deficiency and notice dark urine, contact a clinician promptly for individual advice. Drink fluids if you are able to do so, and keep note of recent illness, medicines, supplements, foods and chemical exposures. Do not take a new medicine or stop prescribed treatment without speaking to a clinician, unless you have been given a specific emergency plan.

Keep your G6PD status recorded in your health information and tell pharmacists and healthcare professionals before medicines are prescribed or bought. They can check whether a treatment is suitable for you.

Seek urgent medical care for dark urine with severe weakness, dizziness or fainting, shortness of breath, chest pain, rapid heartbeat, yellowing of the eyes or skin, reduced urine output, severe abdominal or back pain, or a high fever. Children with dark urine or jaundice need prompt assessment. These signs can occur during significant red blood cell breakdown or another condition requiring treatment.

Ask whether this could be haemolysis, which tests may clarify the cause, whether you need monitoring of kidney function or blood count, and which medicines, foods or chemicals you should avoid. Bring a list of every recent medication and supplement.