From the Guidelines
Dark urine is primarily caused by dehydration, when your body lacks sufficient water to dilute waste products in urine, as well as other factors such as certain foods, medications, and medical conditions, including liver and kidney issues, urinary tract infections, and bleeding in the urinary tract, as noted in recent studies 1.
Common Causes of Dark Urine
- Dehydration: lack of sufficient water to dilute waste products in urine
- Certain foods: beets, blackberries, rhubarb
- Medications: rifampin, phenazopyridine, some laxatives
- Medical conditions: liver problems (hepatitis, cirrhosis), kidney issues, urinary tract infections, bleeding in the urinary tract
- Metabolic disorders and muscle injuries: release of myoglobin into the bloodstream
Importance of Hydration
Increasing water intake to 6-8 glasses daily can help maintain proper hydration and normal urine color in many cases, as hydration status is a key factor in determining urine color 1.
When to Consult a Healthcare Provider
If you notice persistently dark urine, especially if accompanied by other symptoms like pain, fever, or fatigue, you should consult a healthcare provider, as dark urine can be a sign of underlying health conditions, including urinary tract infections and bleeding in the urinary tract, which can have serious consequences if left untreated, such as increased risk of cancer-specific mortality and all-cause mortality 1.
Recent Guidelines and Recommendations
Recent guidelines, such as the 2025 AUA/SUFU guideline, emphasize the importance of proper evaluation and diagnosis of hematuria, including the use of cystoscopy and upper tract imaging, to limit unnecessary risks and costs associated with over-evaluation and under-evaluation of patients with hematuria 1.
From the Research
Causes of Dark Urine
- Dehydration is a potential cause of dark urine, as it can lead to a decrease in blood volume and a subsequent decrease in blood flow to the kidneys, resulting in a more concentrated urine 2
- Certain medical conditions, such as liver disease, can also cause dark urine due to the buildup of waste products in the blood 3
- Medications, such as rifampicin, can interact with other drugs and affect kidney function, potentially leading to changes in urine color 4
Underlying Mechanisms
- Dehydration can lead to the activation of the aldose reductase-fructokinase pathway, which can cause damage to the kidneys and lead to changes in urine color 2
- Liver disease can cause an imbalance in electrolytes and fluids, leading to changes in urine color and concentration 3
- Pharmacokinetic interactions between medications can affect kidney function and lead to changes in urine color 4
Related Factors
- Heat-associated dehydration can increase the risk of chronic kidney disease, which can cause changes in urine color 2
- Acute kidney injury can occur in patients with liver disease, leading to changes in urine color and concentration 3
- Close monitoring of blood pressure and kidney function is necessary in patients taking certain medications, such as rifampicin, to prevent changes in urine color and other complications 4