Sodium-glucose cotransporter-2 (SGLT2) inhibitors are oral medications used for type 2 diabetes, and increasingly for heart failure and chronic kidney disease. These drugs function through a mechanism involving the kidneys, and one potential side effect is an increased possibility of developing urinary tract infections (UTIs). While data from some clinical trials have not shown a significant increase in UTI risk compared to a placebo, other real-world studies indicate a higher incidence, making it a recognized concern.
The Primary Function of SGLT2 Inhibitors
The kidneys continuously filter waste from the blood while retaining necessary substances. One substance the body reabsorbs and returns to the bloodstream during this filtering process is glucose. This reabsorption is carried out by proteins, and the primary one responsible in the kidneys is the sodium-glucose cotransporter 2, or SGLT2.
SGLT2 inhibitors work by blocking these transport proteins in the proximal tubules of the nephron. When the SGLT2 protein is inhibited, it can no longer effectively move glucose from the filtered fluid back into the blood. This action leads to more glucose being passed out of the body through the urine, a condition known as glycosuria. This process helps lower blood sugar levels and also contributes to a reduction in blood pressure and volume overload.
The Link Between Excess Sugar in Urine and UTIs
The urinary tract is a sterile environment, but high levels of glucose in the urine disrupt this balance. This sugar-rich urine creates a favorable environment for bacteria to flourish, providing a food source that allows them to multiply rapidly.
The bacterium most commonly responsible for UTIs is Escherichia coli (E. coli), which resides in the gut. If these bacteria enter the urinary tract, the glucose-laden urine can fuel their growth and lead to an infection. The medication does not introduce bacteria; it creates conditions where bacteria that enter the urethra can thrive more easily.
While the connection seems direct, some scientific studies have shown inconsistent results regarding the risk. A 2015 FDA warning highlighted a risk for severe UTIs based on reported cases. However, some large randomized controlled trials did not find a significant difference in UTI rates between SGLT2 inhibitors and placebo, though real-world observational studies have sometimes shown a higher incidence. This discrepancy may be due to various factors, including different patient populations and study designs.
Identifying a Urinary Tract Infection
Recognizing the symptoms of a UTI is the first step toward seeking timely treatment. One of the most common signs is a strong and persistent urge to urinate, often with a burning or painful sensation. Individuals might also find they are passing very frequent, but small, amounts of urine.
Changes in the urine itself can also indicate an infection. The urine may appear cloudy, or in some cases, red, pink, or cola-colored, which is a sign of blood. Another common symptom is pelvic pain, particularly in the center of the pelvis. If the infection spreads to the kidneys, it can cause more severe symptoms like back pain, fever, and nausea.
Risk Reduction and Management
Patients taking SGLT2 inhibitors can take proactive steps to lower their risk of a UTI. Maintaining good hydration by drinking plenty of water is fundamental, as it helps dilute the urine and flush the urinary system more regularly. Good personal hygiene is also a significant factor in preventing the introduction of bacteria into the urinary tract.
For women, urinating shortly after sexual intercourse can help flush out any bacteria that may have entered the urethra. It is important for anyone who suspects they have a UTI to contact their healthcare provider immediately. Prompt medical treatment with antibiotics can clear the infection and prevent serious complications.
Do not stop taking a prescribed SGLT2 inhibitor without first consulting your doctor. These medications provide substantial benefits for managing diabetes, heart, and kidney conditions. The risk of UTIs is a manageable side effect that can be addressed through vigilance and communication with a healthcare professional.