Methenamine

Overview

It's an option for people who want to avoid long-term antibiotics. It doesn't treat an active infection.

What it's used for

• Preventing frequent UTIs

How to take it

• Take it twice a day (hippurate form).
• Avoid large amounts of antacids and citrus juices that make urine less acidic.

Your dose depends on your health and other medicines. Always follow your prescription label, and ask your pharmacist if anything is unclear.

Side effects

Common side effects

• Nausea
• Upset stomach
• Rash

Warnings

• Not for people with severe kidney or liver disease or dehydration.

Other medicines, foods, and alcohol

• Sulfa antibiotics shouldn't be taken with it.
• Antacids and bicarbonate make it less effective.

Tell your provider and pharmacist about every medicine, vitamin, and supplement you take.

Pregnancy and breastfeeding

Ask your provider.

Missed doses, overdose, and storage

If you miss a dose

Take it as soon as you remember. If it's almost time for the next dose, skip the missed one. Don't double up, and still finish the full course.

If someone takes too much

Call Poison Control at 1-800-222-1222 or get help online at poison.org. Call 911 if the person collapses, has a seizure, has trouble breathing, or can't be woken.

Storing it

Store at room temperature, away from heat and moisture (not in the bathroom), and out of reach of children and pets.

Conditions it's used for

• Urinary tract infection (UTI)