Urex

DRUG DESCRIPTION

UREX (methenamine hippurate) is a urinary tract antiseptic drug. Each white, scored UREX tablet contains methenamine hippurate 1 g (see HOW SUPPLIED). UREX (methenamine hippurate) tablets also contain: magnesium stearate, povidone and saccharin sodium. Chemically, methenamine hippurate is the hippuric acid salt of methenamine (hexamethylenetetramine).

Structural formula:

C15H21N5O3
Molecular Weight 319.37

What are the possible side effects of methenamine (Hiprex, Mandelamine, Urex)?

If you experience any of the following serious side effects, stop taking methenamine and seek emergency medical attention or contact your doctor immediately:

  • an allergic reaction (shortness of breath; closing of the throat; swelling of the lips, face, or tongue; or hives;
  • lower back or side pain;
  • blood in urine; or
  • increasingly painful or difficult urination.

Other, less serious side effects may be more likely to occur. Continue to take methenamine and talk to your...

Read All Potential Side Effects and See Pictures of Urex

What are the precautions when taking methenamine hippurate (Urex)?

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. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney problems, liver problems, dehydration.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

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...

Read All Potential Precautions of Urex


Urex Consumer (continued)

SIDE EFFECTS: Nausea, vomiting, diarrhea, abdominal cramps, and loss of appetite may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Painful or difficult urination may occur with methenamine, although less often. Report these side effects to your doctor, who may need to lower your dose of methenamine or change your treatment to make your urine less acidic.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Taking higher than recommended doses of methenamine may cause bladder irritation, painful/frequent urination, and bloody/pink urine. Tell your doctor immediately if you have any of these symptoms.

Tell your doctor immediately if any of these unlikely but serious side effects occur: mouth sores, unusual headache, ringing in the ears, muscle cramps, swelling of the arms/legs.

A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: 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. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney problems, liver problems, dehydration.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

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.


Urex Patient Information Including Side Effects

Brand Names: Hiprex, Mandelamine, Urex

Generic Name: methenamine (Pronunciation: meh THEH na meen)

  • What is methenamine (Urex)?
  • What are the possible side effects of methenamine (Urex)?
  • What is the most important information I should know about methenamine (Urex)?
  • What should I discuss with my healthcare provider before taking methenamine (Urex)?
  • How should I take methenamine (Urex)?
  • What happens if I miss a dose (Urex)?
  • What happens if I overdose (Urex)?
  • What should I avoid while taking methenamine (Urex)?
  • What other drugs will affect methenamine (Urex)?
  • Where can I get more information?

What is methenamine (Urex)?

Methenamine is a urinary antiinfective medicine. Methenamine fights bacteria in the urine and bladder.

Methenamine may be used to treat and prevent urinary tract infections.

Methenamine may also be used for purposes other than those listed here.

What are the possible side effects of methenamine (Urex)?

If you experience any of the following serious side effects, stop taking methenamine and seek emergency medical attention or contact your doctor immediately:

  • an allergic reaction (shortness of breath; closing of the throat; swelling of the lips, face, or tongue; or hives;
  • lower back or side pain;
  • blood in urine; or
  • increasingly painful or difficult urination.

Other, less serious side effects may be more likely to occur. Continue to take methenamine and talk to your doctor if you experience

  • nausea or upset stomach;
  • decreased appetite; or
  • skin rash.

Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome. You may report side effects to FDA at 1-800-FDA-1088.

What is the most important information I should know about methenamine (Urex)?

Take all of the methenamine that has been prescribed for you even if you begin to feel better. Symptoms may start to improve before the infection is completely treated.

Take each dose with a full glass of water. Plenty of fluid should be consumed while taking methenamine.

Your healthcare provider may recommend drinking additional water and/or certain fruit juices (e.g., cranberry, plum, prune) and increased protein in the diet while taking methenamine to ensure adequate hydration and acidity of the urine. It may also be recommended to avoid citrus fruits and juices (e.g., orange, grapefruit, lemon), milk and dairy products, and antacids during treatment with methenamine. These products may decrease the effectiveness of methenamine. Follow your healthcare provider's instructions.

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