Based on NIH | Can omeprazole cause frequent urination, and how common is this side effect?

Omeprazole can be associated with urinary symptoms such as frequent urination, but this appears to be uncommon. Official product information lists “urinary frequency” among postmarketing urogenital adverse reactions, alongside conditions like urinary tract infection and interstitial nephritis. ^[1] Consumer-facing safety information also advises seeking care if there is a decrease in urine output or blood in the urine, which can signal a kidney problem rather than simple frequency. ^[2]

What the labels say

• Urinary frequency is listed as a reported adverse reaction. Multiple official omeprazole labels group “urinary frequency” with other urogenital events (e.g., hematuria, proteinuria, elevated creatinine, microscopic pyuria, UTI). ^{[1] [3]}
• Warning signs to watch for: Patient instructions highlight a “decrease in the amount that you urinate” or blood in urine as reasons to call a clinician, reflecting concern for possible kidney injury. ^{[2] [4]}

How common is it?

• Frequency category is not specified in the labels. Urinary frequency is included in postmarketing reports without a quantified rate, which typically means it occurred rarely enough in trials that precise incidence could not be established. ^[1]
• By contrast, better-characterized PPI risks (e.g., C. difficile diarrhea, bone fractures in certain settings) have stronger incidence data, indicating that urinary frequency is likely an infrequent complaint. ^{[5] [6]}

Why might urinary symptoms occur?

• Benign mechanism (rare): Some people may experience urinary frequency without other abnormalities; the exact mechanism is unclear and not well documented. ^[1]
• Kidney inflammation link (uncommon but important): Omeprazole and other proton pump inhibitors can cause acute interstitial nephritis (AIN), an immune-mediated kidney inflammation that classically presents with changes in kidney function and urinary findings (e.g., pyuria), and may alter urination patterns. ^{[7] [8]} AIN is considered uncommon but clinically significant because it can impair kidney function and sometimes requires treatment. ^{[7] [8]}

When to seek care

• Seek prompt medical advice if you notice a marked decrease in urine volume, blood in the urine, flank/loin pain, fever, swelling, or sudden fatigue, as these can indicate kidney involvement rather than simple urinary frequency. ^{[2] [4]}
• If urinary frequency is the only symptom and is mild, it may settle, but discussing it with a clinician is still reasonable, especially if it persists or is bothersome. ^[1]

Practical tips

• Review other causes: Caffeine, alcohol, high fluid intake, urinary tract infections, diuretics, diabetes, and prostate conditions can also cause frequent urination; ruling these out is helpful. ^[1]
• Medication check: If symptoms began after starting omeprazole, a clinician might consider dose timing adjustments, a trial discontinuation, or switching to an H2 blocker if appropriate, balancing this against your acid-related symptoms. ^{[5] [6]}

Bottom line

• Yes, urinary frequency has been reported with omeprazole, but it appears uncommon and is not assigned a clear incidence in official labeling. ^[1]
• Because omeprazole can rarely affect the kidneys, any significant urinary changes especially decreased urine, blood in urine, or pain deserve prompt medical evaluation. ^{[2] [4]}