Prodrug hydrolyzed to formaldehyde in acidic urine (pH <5.5), which denatures bacterial proteins and nucleic acids. Only works in the bladder — requires acidic urine. Used for chronic UTI prevention, not acute treatment.
At a glance
Storage
Store at room temperature, protect from moisture
Dosing
Used for chronic/recurrent UTI prophylaxis — NOT for acute UTI treatment
Used for recurrent UTI prevention in cats
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet.
Find a vet near you →Safety
Urine pH (must be <6.5 for efficacy)Urine culture q1–3 monthsRenal function
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet.
Find a vet near you →Interactions
No documented interactions.
FAQs
Frequently asked questions
›What is Methenamine?
Methenamine is a urinary antiseptic used in pets. Prodrug hydrolyzed to formaldehyde in acidic urine (pH <5.5), which denatures bacterial proteins and nucleic acids. Only works in the bladder — requires acidic urine. Used for chronic UTI prevention, not acute treatment.
›What is Methenamine used for in pets?
Methenamine is used in veterinary medicine for: Used for chronic/recurrent UTI prophylaxis — NOT for acute UTI treatment; Used for recurrent UTI prevention in cats.
›What is the Methenamine dose for dogs?
For dogs, Methenamine is typically dosed as follows — Used for chronic/recurrent UTI prophylaxis — NOT for acute UTI treatment: 10–20 mg/kg PO q12h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What is the Methenamine dose for cats?
For cats, Methenamine is typically dosed as follows — Used for recurrent UTI prevention in cats: 250–500 mg/cat PO q12h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›Does Methenamine need a prescription?
Yes. Methenamine is a prescription medication and should only be administered under veterinary supervision.
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet.
Find a vet near you →References
References
The PetCare.AI drug reference is built from 13 authoritative sources cited across 580 drug monographs.
Textbooks & handbooks — 5
- Plumb's Veterinary Drug Handbook
- Withrow & MacEwen's Small Animal Clinical Oncology
- Merck Veterinary Manual
- NRC Nutrient Requirements of Dogs and Cats
- Veterinary Pharmacology and Therapeutics (Riviere & Papich)
Clinical guidelines & consensus — 4
- ASPCA Animal Poison Control Center Guidelines
- AAHA Diabetes Management Guidelines
- ASPCA Poison Control Guidelines
- RECOVER CPR Guidelines
Journals & peer-reviewed studies — 2
- EPIC Study (J Vet Intern Med 2016)
- JVIM FAT CAT Study
Regulatory & approvals — 1
- CDSCO Veterinary Drug Approval Registry (1969–2026)
Databases — 1
- Washington State University VCPL MDR1 Database