Methenamine is a medication that is utilized to prevent or manage recurrent urinary tract infections that are caused by specific bacteria. It should not be used to treat an active infection, as antibiotics must be administered initially to cure the infection.
Methenamine operates by preventing the growth of bacteria in the urine, and it contains an element that helps to render the urine acidic. This acidic environment causes the methenamine to convert into formaldehyde, which kills the bacteria.
Uses and Dosage
Follow your doctor’s instructions and take this medication orally as directed. The dosage prescribed depends on the brand of methenamine you have been given, your medical condition, and your response to treatment. In children, the dosage also takes into account their age and weight.
To achieve optimal results, maintain a certain level of acidity in your urine. Your doctor may assess the pH level of your urine and advise you on ways to increase acidity, such as taking vitamin C or drinking cranberry juice, avoiding foods that reduce acidity or increase alkalinity, and adjusting alkalinizing medications. To help you remember, take the drug at the same time(s) every day.
Even if you feel better, continue taking the medication for the full duration prescribed. Skipping doses or discontinuing the medication prematurely may allow the bacteria to thrive, resulting in a recurrence of the infection and making the bacteria more difficult to treat. Do not take more than the recommended dosage as this may increase the likelihood of side effects.
If you experience symptoms of a urinary tract infection, such as painful or frequent urination or a burning sensation, notify your doctor immediately.
Some side effects may occur that usually do not need medical attention:
- upset stomach
- stomach cramps
- loss of appetite
Inform your healthcare provider immediately if you experience any serious side effects:
- skin rash
Prior to taking methenamine, inform your healthcare provider or pharmacist if you have any allergies, including allergies to formaldehyde, or if you have any other allergies. This product may contain inactive ingredients that could result in allergic reactions or other complications.
Before using this medication, be sure to disclose your medical history, particularly if you have kidney or liver problems or if you are dehydrated.
If you are pregnant, you should only use this medication if it is absolutely necessary. Discuss the potential risks and benefits with your doctor.
It is unclear how this drug may affect a nursing infant. Consult with your doctor before breastfeeding while taking this medication.
Form and Strength
Hiprex is available in the following forms and strengths:
How long does it take Hiprex to reach the bladder?
Within 30 minutes after ingestion of a single 1-gram dose of Hiprex, antibacterial activity is demonstrable in the urine.
Does Hiprex increase urination?
Large doses of Hiprex (higher than recommended) can cause bladder irritation, frequent and painful urination, protein in your urine, and blood in your urine.