Methenamine (By mouth)
meth-EN-a-meen
Treats bladder and kidney infections.
Drug classes
Antiseptic (About this – PubMed Health)
Uses
Uses of This Medicine
Methenamine belongs to the family of medicines called anti-infectives. It is used to help prevent and treat infections of the urinary tract. Methenamine is available only with your doctor’s prescription.
Other uses (PubMed Health)
How To Use
Tablet, Coated Tablet, Liquid, Granule
Your doctor will tell you how much medicine to use and how often. Do not use more medicine or use it more often than your doctor tells you to.
Drink plenty of water or cranberry juice every day while you are using this medicine.
Keep using this medicine for the full time treatment time. If you stop using this medicine too soon, your infection may come back.
Swallow the tablet or coated tablet whole with a full glass of water. Do not chew, crush, or break it.
Measure the oral liquid with a measuring spoon or dropper. Shake the bottle before using. Take with a full glass of water or with food.
Empty the granules into a full glass of water and let them dissolve before you drink the mixture.
If a dose is missed:
Take the missed dose as soon as possible.
If it is almost time for your next regular dose, wait until then to take the medicine and skip the missed dose.
You should not use two doses at the same time.
How to Store and Dispose of This Medicine:
Store in the original tightly closed, light-resistant container, away from moisture and direct light. Do not freeze.
Keep all medicine away from the reach of children.
Drugs and Foods to Avoid
Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.
Make sure your doctor knows if you are also using a sulfa drug (such as Bactrim® or Septra®).
It is best to avoid using antacids (such as Maalox® or Mylanta®) while taking methenamine.
This medicine works best in acidic urine. Drinking cranberry juice will help keep urine acidic. Avoid foods that lower the acid in your urine, such as nuts or milk and other dairy products.
When Not To Use
You should not use this medicine if you have ever had an allergic reaction to methenamine or tartrazine.
Warnings
Check with your doctor before using this medicine if you have liver or kidney problems, severe dehydration, or other medical problems.
If you are pregnant or breastfeeding, talk to your doctor before taking this medicine
Possible side effects
Summary More details
Call your doctor right away if you notice any of these side effects:
If you notice these less serious side effects, talk with your doctor:
Pain when going to the bathroom (urinating)
If you notice other side effects that you think are caused by this medicine, tell your doctor.
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
More side effects of this drug
Brand names include
Hiprex, Mandelamine, Urasal, Urex
There may be other brand names for this medicine.
