Methenamine is an anti-infective medication that is used to
help prevent infections of the urinary tract. It is usually
prescribed on a long-term basis for individuals with a history
of repeated or chronic
urinary tract infections.
Proper Usage
Before you start taking this medication, check your urine
with phenaphthazine paper or another test to see if it is
acidic. Your urine must be acidic (pH 5.5 or below) for this
medicine to work properly. Consult your health care
professional about possible changes in your diet if necessary
to increase the acidity of your urine (e.g., avoiding citrus
fruits and juices, milk and other dairy products, antacids;
eating more protein and foods such as cranberries and
cranberry juice with added vitamin C, prunes, or plums).
Precautions
The effects of methenamine in pregnancy have not been
studied in either humans or animals. Individual case reports
have not shown that this medication causes birth defects or
other problems in humans.
Methenamine passes into breast milk but has not been
reported to cause problems in nursing infants.
Possible Side Effects
Side effects that typically go away as your body adjusts to
the medication and do not require medical attention unless
they continue or are bothersome: nausea; vomiting.
Unusual side effects that should be reported immediately to
your physician: skin rash.
