Methenamine

• Uses Temporarily relieves: pain & burning • frequency and urgency of urination

Directions: Adults and children 12 years and over: take 2 tablets with a full glass of water 3 times a day. Drink plenty of fluids. Children under 12 years: ask a doctor

Reye's syndrome: Children and teenagers who have or are recovering from chicken pox or flu-like symptoms should not use this product. If changes in behaviour with nausea and vomiting occur, consult a doctor because these symptoms could be an early sign of Reye's syndrome, a rare but serious illness. Stomach bleeding warning: This product contains an NSAID, which may cause stomach bleeding. The chance is higher if you: • take other drugs containing prescription or nonprescription NSAIDs (aspirin, ibuprofen, naproxen or others) • have 3 or more alcoholic drinks every day while using this product • have stomach ulcers or bleeding problems • take a blood thinning (anticoagulant) or steroid drug • are age 60 or older • take more or for a longer time than directed Do not use: • if you are on a sodium restricted diet • if you are allergic to salicylates (including aspirin) unless directed by a doctor • if you have stomach problems (such as heartburn, upset stomach, or stomach pain) that persist or recur, or if you have ulcers or bleeding problems unless directed by a doctor Ask a doctor before use if you have • frequent, burning urination for the first time • the stomach bleeding warning applying to you • history of stomach problems, such as heartburn • high blood pressure • heart disease • liver cirrhosis • bleeding problems • diuretic use • ulcers • kidney disease • reached age 60 or older Ask a doctor or pharmacist before use if you are • taking any other drug containing an NSAID (prescription or nonprescription) • taking a blood thinning (anticoagulant), steroid, diabetes, gou…

• Jul 5, 1967NDANDA016151Quagen
• Sep 9, 1976NDANDA017681Esjay Pharma
• Jul 5, 2016ANDAANDA205661Aurobindo Pharma Ltd
• Aug 1, 2019ANDAANDA212172Micro Labs
• Nov 27, 2020ANDAANDA210068Ingenus Pharms Llc
• Dec 1, 2023ANDAANDA217675Jubilant Cadista
• Mar 10, 2025ANDAANDA219661Zydus Lifesciences

1. 1Urinary Tract Infection2029.5%
2. 2Fatigue1466.9%
3. 3Nausea1446.8%
4. 4Diarrhoea1366.4%
5. 5Headache1286.0%
6. 6Drug Ineffective1205.7%
7. 7Pain1105.2%
8. 8Fall1085.1%
9. 9Dizziness1065.0%
10. 10Off Label Use924.3%
11. 11Asthenia884.2%
12. 12Malaise844.0%
13. 13Arthralgia823.9%
14. 14Product Dose Omission Issue823.9%
15. 15Vomiting793.7%

Recent PubMed references pinned to Methenamine as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

• Implications for methenamine hippurate use in recurrent urinary tract infection management: Formaldehyde resistance and altered urinary composition.
  PLoS pathogens · 2026 · Hodgkinson NC, Al-Rubaye T, Reed TCP, et al.
  PMID 41875198DOI 10.1371/journal.ppat.1014081
• Urinary pH, Methenamine, and Formaldehyde Levels in the Management of Postmenopausal Women With Recurrent Urinary Tract Infections: A 1-Year Prospective Pilot Study With Extended Follow-up.
  Urology · 2026 · Zimmern P, Kusin S, Fan E, et al.
  PMID 41565162DOI 10.1016/j.urology.2026.01.007
• Development and Validation of an LC-MS/MS Method for the Quantification of Methenamine in Raw Milk and Bovine Muscle and Its Application to Incurred Samples.
  Molecules (Basel, Switzerland) · 2025 · Park S, Hong CO, Kim SH, et al.
  PMID 41471829DOI 10.3390/molecules30244807
• Preservation of tophi in the modified Gomori methenamine silver procedure for urates.
  Journal of histotechnology · 2026 · Van Aken L, Bielli A, Esposito JA, et al.
  PMID 40899472DOI 10.1080/01478885.2025.2550125
• Methenamine hippurate as prophylaxis for recurrent urinary tract infections in older women-a triple-blind, randomised, placebo-controlled, phase IV trial (ImpresU).
  Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases · 2025 · Heltveit-Olsen SR, Arnljots ES, Sundvall PD, et al.
  PMID 40669691DOI 10.1016/j.cmi.2025.07.006
• Green synthesis of a urea-melamine-hexamethylenetetramine resin for efficient extraction and determination of berberine hydrochloride in Pudilan antiphlogistic oral liquid.
  Journal of chromatography. A · 2025 · Wang H, Wang M, Zhang J, et al.
  PMID 40652811DOI 10.1016/j.chroma.2025.466196
• Methenamine hippurate for the management and prophylaxis of recurrent urinary tract infections: a scoping review protocol.
  BMJ open · 2025 · Chatterjee A, Ali I, Wong F, et al.
  PMID 40306981DOI 10.1136/bmjopen-2025-100458
• Effectiveness of methenamine hippurate in preventing urinary tract infections: an updated systematic review, meta-analysis and trial sequential analysis of randomized controlled trials.
  BMC urology · 2025 · Hobaica NC, De Oliveira GC, Porto BC, et al.
  PMID 39955521DOI 10.1186/s12894-025-01708-8

The 10 most recently updated of 23 ClinicalTrials.gov registrations naming Methenamine as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• A Clinical Trial of Extended (High) Treatment Dose Antibiotics in Combination With Methenamine Hippurate Compared to the Standard of Care (Either Prophylactic (Low) Dose Antibiotic Treatment or Methenamine Hippurate) in Females With Chronic Urinary Tract Infection
  Recruiting · Phase 2 · Interventional · 192 enrolled · University College, London
  NCT07202949updated 2026-04-23
• A Multidisciplinary, Multimodal Bundled Care Approach to Chronic Pelvic Pain
  Terminated · Phase 3 · Interventional · 26 enrolled · Jocelyn Fitzgerald
  NCT05658874updated 2026-04-01
• Efficacy and Mechanism of Action of Methenamine Hippurate (Hiprex™) in Women With Recurring Urinary Tract Infections.
  Terminated · Phase 4 · Interventional · 14 enrolled · University of Texas Southwestern Medical Center
  NCT04709601updated 2026-02-24
• Vitamin C and Hiprex in rUTI
  Not yet recruiting · Early phase 1 · Interventional · 20 enrolled · University Hospitals of North Midlands NHS Trust
  NCT06710899updated 2026-02-11
• Methenamine Hippurate Following Intradetrusor OnabotulinumtoxinA Injection
  Not yet recruiting · Phase 4 · Interventional · 164 enrolled · Women and Infants Hospital of Rhode Island
  NCT06953271updated 2025-05-01
• Is Methenamine Prophylaxis for Urinary Tract Infection After Midurethral Sling as Effective as Antibiotic Prophylaxis?
  Recruiting · Interventional · 190 enrolled · Atlantic Health System
  NCT06810687updated 2025-02-07
• The Effect of Methenamine Hippurate to Reduce Antibiotic Prescribing in Elderly Women With Recurrent UTI
  Completed · Phase 4 · Interventional · 289 enrolled · University of Oslo
  NCT04077580updated 2024-09-03
• Oral Probiotic Supplementation in Pregnancy to Reduce Group B Streptococcus Colonization
  Unknown · Phase 3 · Interventional · 168 enrolled · University of British Columbia
  NCT03407157updated 2023-09-13
• Renal Biopsy Unexplained Elevated Serum Creatinine
  Completed · Observational · 210 enrolled · Assiut University
  NCT03586531updated 2023-07-19
• Urinary Track Infection Prevention After Urogynecological Surgery
  Completed · Phase 2 · Interventional · 185 enrolled · TriHealth Inc.
  NCT03818321updated 2022-11-14

Frequently asked questions

What is Methenamine used for?

According to FDA labeling, Methenamine carries indications including: Uses Temporarily relieves: pain & burning • frequency and urgency of urination. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Methenamine?

Methenamine is classified as Other antibacterials, Cellular Activity Alteration.

What are the brand names for Methenamine?

Methenamine is marketed under brand names including Azo Urinary Tract Defense, Cystex, Hiprex, Hyophen, Phosphasal, Prosed DS, Urelle, Uretron DS.