How Methenamine Hippurate (Hiprex) Helps Prevent UTIs in Seniors
Urinary tract infections (UTIs) are one of the most common infections among older adults—and they don’t always appear the same way. Instead of the typical burning sensation, some seniors experience confusion, fatigue, or sudden changes in behavior.
That’s why prevention is key—and one of the medications doctors often recommend for this purpose is Methenamine Hippurate, also known by its brand name Hiprex.
What Is Methenamine Hippurate?
Methenamine Hippurate is a prescription medication used to prevent recurrent UTIs, particularly for individuals who experience them frequently. It works by keeping urine slightly acidic, which helps inhibit bacterial growth inside the bladder.
How the Drug Works In The Body
Hiprex breaks down in acidic urine to release formaldehyde, which helps prevent bacteria from multiplying in the bladder
Why not Antibiotics to treat repeated UTI infections?
Long-term antibiotic use is no longer the preferred prevention method. Over time, bacteria can become resistant—making infections harder to treat—and antibiotics may also disrupt the body’s healthy bacteria that protect against infection.
Hiprex offers a safer alternative.
When taken as directed, this simple tablet helps protect urinary health and reduces the need for frequent antibiotic courses—a major benefit for seniors.
Hydration Helps Hiprex Work Better
This medication relies on the body’s natural urine acidity to release bacteria-fighting formaldehyde in the bladder. Drinking 6–8 glasses of water each day helps maintain steady urine flow, preventing bacteria from collecting and giving the medicine the environment it needs to work effectively.
Older adults who don’t drink enough water may experience more concentrated urine, which can irritate the bladder and reduce the drug’s effectiveness. To stay on track, keep a water bottle close by, sip throughout the day, and aim for pale-yellow urine—a simple sign you’re staying well-hydrated.
-
Most people can take it safely for months or years under medical supervision. If someone has significant kidney or liver disease, or is severely dehydrated, methenamine hippurate is not appropriate.
-
Always review your full medication list with your doctor or pharmacist. At Your Health, our providers can help review and consolidate your medications to ensure there are no potential conflicts or interactions before starting Hiprex.
-
Take it as soon as you remember—unless it’s almost time for your next dose. Never double up.
If you have questions or want to discuss whether Hiprex is right for you or your loved one, call our triage nurses at 1-800-491-0909 (option 9). A nurse will answer or return your call promptly
References:
Evaluation of methenamine for urinary tract infection prevention in women: mechanism of action and clinical evidence. PMC. 2023. “Its mechanism of action is driven by the formation of bactericidal formaldehyde…” PMC
National Institute for Health and Care Excellence (NICE) Guideline NG112: Urinary tract infection (recurrent): antimicrobial prescribing. December 2024. NCBI+2NCBI+2
Methenamine hippurate for preventing urinary tract infections: systematic review and meta-analysis. PMC. 2020. PMC
HIPREX® (methenamine hippurate tablets USP) United States Food & Drug Administration label. FDA Access data
Evidence that methenamine is as good as antibiotics at preventing recurrent UTIs. NIHR Evidence
Review of antibiotic prophylaxis in the management of recurrent urinary tract infections. ASAP Guidance. ” ASAP