Prescription Required 
Formulation : 
Description
Indications
Methenamine is employed to prevent or manage recurrent urinary tract infections caused by specific bacteria. It is not intended for treating an active infection. Methenamine functions by inhibiting the growth of bacteria in the urine.
Additionally, this medication contains an ingredient that helps acidify the urine. When the urine becomes acidic, methenamine undergoes a transformation into formaldehyde, which acts to eliminate bacteria.
Uses and Dosage
Take this medication orally following your doctor’s instructions. The dosage depends on the specific brand of methenamine prescribed, your medical condition, and your response to treatment. For children, the dosage is also determined by age and weight.
Methenamine is more effective when the urine is more acidic. Your doctor may assess the acidity of your urine (urine pH).
If necessary, your doctor might suggest ways to increase urine acidity, such as taking vitamin C, drinking cranberry juice, limiting foods that decrease acidity or increase alkalinity (such as milk products or most fruits), and adjusting alkalinizing medications. Refer to the Drug Interactions section and adhere to your doctor’s guidance.
To optimize its effectiveness, take this medication at evenly spaced intervals. To aid in remembering, take it at the same time(s) every day.
Continue taking the medication for the entire prescribed duration, even if you start feeling well. Skipping doses or prematurely discontinuing the medication may allow bacteria to persist and grow, leading to a recurrence of the infection and potentially making the bacteria more resistant to treatment.
Adhere to the prescribed dosage, and avoid taking more than directed, as it may increase the risk of side effects.
Inform your doctor if symptoms of a urinary tract infection reoccur, such as burning, painful, or frequent urination.
Regular communication with your healthcare provider is essential for proper monitoring and management of your condition.
Side Effects
Some side effects may occur that usually do not need medical attention:
- nausea
- vomiting
Inform your healthcare provider immediately if you experience any serious side effects:
- mouth sores
- unusual headache
- ringing in the ears
- muscle cramps
- swelling of the arms/legs
- rash
- itching/swelling (especially of the face/tongue/throat)
- severe dizziness
- trouble breathing
Caution
- Before taking methenamine, tell your doctor or pharmacist if you are allergic to it; or to formaldehyde; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems.
- Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney problems, liver problems, dehydration.
- During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.
- This drug passes into breast milk and the effect on a nursing infant is unknown. Consult your doctor before breast-feeding.
Form and Strength
Mandelamine is available in the following forms and strengths:
- Mandelamine tablet:
- 500 mg
FAQ
Is Mandelamine an antibiotic?
Yes, Mandelamine is an antibiotic, but not the type that treats active infections. Instead, Mandelamine helps prevent and control chronic UTIs in people who need long-term treatment.
Does Mandelamine make you urinate more?
No, Mandelamine shouldn’t make you urinate more if you take it as directed. But there have been reports of people experiencing frequent urination after taking higher doses.
Resources
- https://www.goodrx.com/methenamine-hippurate/what-is#faqs
- https://www.mayoclinic.org/drugs-supplements/methenamine-oral-route/side-effects/drg-20064676
- https://www.webmd.com/drugs/2/drug-5658/mandelamine-oral/details
- https://www.healthlinkbc.ca/medications/methenamine-oral
- https://www.drugs.com/cons/mandelamine.html
