GENERIC NAME: METHENAMINE - ORAL (meth-EN-a-meen)
BRAND NAME(S): Hiprex, Mandelamine, Urex
USES: Methenamine is used to prevent or control returning urinary tract infections caused by certain bacteria. It is not used to treat an active infection. Other antibiotics must be used first to treat and cure the infection. Methenamine is an antibiotic that stops the growth of bacteria in urine. This medication also contains an ingredient that helps to make the urine acidic. When the urine is acidic, methenamine turns into formaldehyde to kill the bacteria.This antibiotic is effective only against bacterial infections in the urinary tract. It will not work for other types of bacterial infections (such as in the blood) or for viral infections (such as the common cold or flu). Unnecessary use or misuse of any antibiotic can lead to its decreased effectiveness.
HOW TO USE: Take this medication by mouth as directed by your doctor. Dosage is based on the brand of methenamine you are prescribed, your medical condition, and your response to treatment. For children, dosage is also based on age and weight.Methenamine works better if your urine is more acidic. Your doctor may test the acidity of your urine (urine pH). If necessary, your doctor may recommend ways to increase urine acidity (such as by taking vitamin C/drinking cranberry juice, limiting foods that decrease acidity/increase alkalinity such as milk products/most fruits, adjusting alkalinizing medications). See also Drug Interactions section. Follow your doctor's instructions.Antibiotics work best when the amount of medicine in your body is kept at a constant level. Therefore, take this drug at evenly spaced intervals. To help you remember, take it at the same times each day.Continue to take this medication for the full time prescribed, even if you feel well. Skipping doses or stopping the medication too early may allow bacteria to continue to grow, which may result in a return of the infection and make the bacteria more difficult to treat (resistant). Do not take more of this drug than directed because it may increase your chance of side effects.Tell your doctor if symptoms of a urinary tract infection return (such as burning/painful/frequent urination).
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You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
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