Methenamine Hippurate (Hiprex) Uses

Methenamine is used for long-term suppressive treatment and prevention of recurrent urinary tract infections. It is prescribed after an active infection has been cleared with other antibiotic treatment. 

Note: Methenamine and other antibiotics are not effective against viral infections such as the common cold and flu. Taking antibiotics when they are not needed can lead to antibiotic resistance and make bacterial infections harder to treat in the future. The increasing prevalence of antibiotic resistance in the general population is a public health concern worldwide.

There may be other uses of methenamine drug therapy—your doctor or health system pharmacists can give you further information.

Methenamine Hippurate (Hiprex) Mechanism of Action

Methenamine works by killing the bacteria that cause a urinary tract infection, such as E. coli, staphylococci, enterococci, Proteus, and Pseudomonas. It is also used for preventing urinary tract infections that keep coming back. 

Methenamine antibiotic works best when the urine is acidic. The drug is rapidly absorbed from the gastrointestinal tract and excreted into the urine, where it breaks down into formaldehyde and ammonia in an acid urine.

Methenamine Hippurate (Hiprex) Doses

Methenamine hippurate comes in the form of an enteric-coated tablet, liquid, and dry granules to take by mouth.

The recommended doses of methenamine hippurate for the treatment and prevention of recurrent UTI are:

• 1 gram every 12 hours (morning and night) for adults and children over 12 years of age. 
• 500 mg to 1 gram every 12 hours (morning and night) for children between 6 and 12 years of age.