What is the cause of hematuria in a 74-year-old male taking losartan (Angiotensin II receptor antagonist)/hydrochlorothiazide (HCTZ) (thiazide diuretic)?

From the Guidelines

You should see a doctor immediately for blood in your urine, especially as a 74-year-old male taking losartan/HCTZ. Blood in urine (hematuria) requires prompt medical evaluation as it can indicate several serious conditions including urinary tract infections, kidney stones, kidney disease, or potentially bladder or prostate cancer, which are more common in older men 1. While losartan/HCTZ (a blood pressure medication combining an angiotensin receptor blocker with a diuretic) doesn't typically cause hematuria, certain medications and your age increase the importance of proper evaluation. Don't stop your blood pressure medication without medical advice.

Key Considerations

• The presence of gross hematuria has a high association with malignancy, up to 30% to 40%, and therefore, all patients with gross hematuria should have a full urologic workup 1.
• Patients with microhematuria have a low risk of malignancy, ranging from 2.6% to 4%, but this risk increases with age and other factors such as smoking and occupational exposure to chemicals 1.
• The evaluation of hematuria should include a thorough history, physical examination, urinalysis, and serologic testing, as well as cystoscopy in many cases, especially for those with gross hematuria or risk factors for malignancy 1.

Next Steps

• When you see your doctor, they'll likely perform:
  • Urinalysis to confirm blood presence
  • Blood tests to check kidney function
  • Possibly imaging studies (such as CT scans or ultrasound) to evaluate the urinary tract
  • A referral to a urologist for further evaluation and potential procedures like cystoscopy The combination of your age, gender, and symptoms makes this a situation requiring professional medical assessment rather than home management 1.

From the FDA Drug Label

5.3 Renal Function Deterioration Changes in renal function including acute renal failure can be caused by drugs that inhibit the renin-angiotensin system and by diuretics. 7.3 Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) Including Selective Cyclooxygenase-2 Inhibitors (COX-2 Inhibitors) In patients who are elderly, volume-depleted (including those on diuretic therapy), or with compromised renal function, coadministration of NSAIDs, including selective COX-2 inhibitors, with angiotensin II receptor antagonists (including losartan) may result in deterioration of renal function, including possible acute renal failure.

The patient is taking losartan/hctz, which is an angiotensin II receptor antagonist and a diuretic. Given the patient's age (74 years old) and the presence of blood in the urine, it is possible that the patient has compromised renal function.

• The diuretic component of losartan/hctz may cause volume depletion, increasing the risk of renal function deterioration.
• The angiotensin II receptor antagonist component of losartan/hctz may also contribute to renal function deterioration, especially in patients with pre-existing renal impairment. It is essential to monitor renal function periodically in this patient, as recommended in the drug label 2 and 2.

From the Research

Classification of Hematuria

• Hematuria is classified as either gross or microscopic 3
• Gross hematuria has a risk of malignancy greater than 10%, and prompt urologic referral is recommended 3
• Microscopic hematuria most commonly has benign causes, such as urinary tract infection, benign prostatic hyperplasia, and urinary calculi 3

Evaluation of Hematuria

• A thorough history and physical is necessary to determine potential causes and assess risk factors for malignancy 3
• If no benign cause for microscopic hematuria is found, the work-up includes laboratory tests to rule out intrinsic renal disease, imaging of the urinary tract, and referral to nephrology and urology subspecialists 3
• Imaging of the upper tracts is warranted if hematuria involves more than three red blood cells per high-power field on two of three properly collected urinalysis specimens 4

Imaging Options

• Computed tomography urography has significant advantages over traditional excretory urography or intravenous pyelogram 4
• Multidetector computed tomography urography is less susceptible to overlying bowel gas and more sensitive for detection of small tumors and calculi 4
• Ultrasound examination and magnetic resonance imaging can also be useful, particularly in children and pregnant women 4