Indications
- Methenamine is used to prevent or control recurring urinary tract infections caused by specific bacteria.
- It is not intended for treating active infections; antibiotics should be used first for infection treatment and cure.
- Methenamine inhibits bacteria growth in urine and includes an ingredient to acidify urine.
- Acidic urine causes methenamine to convert into formaldehyde, which eliminates bacteria.
- The drug is effective solely against bacterial infections in the urinary tract.
- It does not work for other bacterial infections (e.g., in the blood) or viral infections (e.g., common cold or flu).
- Misuse of antibacterial drugs, including methenamine, can reduce their effectiveness.
Dosage and administration
- Take the medication orally as directed by your doctor.
- Dosage depends on the prescribed brand of methenamine, your medical condition, and your treatment response.
- For children, dosage is determined by age and weight.
- Methenamine is more effective with acidic urine; your doctor may test and recommend ways to increase urine acidity.
- Methods to boost urine acidity may include taking vitamin C, drinking cranberry juice, and limiting certain foods/medications.
- Follow your doctor’s instructions and refer to the Drug Interactions section.
- Take the drug at regular intervals for optimal effectiveness; establish a consistent daily schedule.
- Inform your doctor if urinary tract infection symptoms reoccur (e.g., burning/painful/frequent urination).
Side effects
- Possible side effects of methenamine include nausea, vomiting, diarrhea, abdominal cramps, and loss of appetite.
- If these effects persist or worsen, notify your doctor or pharmacist promptly.
- Painful or difficult urination may occur less frequently; report such side effects to your doctor.
- Your doctor may adjust your methenamine dose or alter treatment if urinary issues arise.
- The prescribed medication is based on the doctor’s assessment of benefits outweighing potential side effects.
- Many users experience this medication without serious side effects.
- Exceeding recommended doses may lead to bladder irritation, painful/frequent urination, and bloody/pink urine; inform your doctor immediately if such symptoms occur.
- Report promptly any serious side effects, such as mouth sores, unusual headache, ringing in the ears, muscle cramps, or swelling of the arms/legs.
- Although rare, a severe allergic reaction may occur; seek medical help if symptoms like rash, itching/swelling, severe dizziness, or trouble breathing arise.
- The provided information does not cover all potential side effects; contact your doctor or pharmacist if you observe other effects not mentioned.
Precautions
- Inform your doctor or pharmacist about any allergies to methenamine, formaldehyde, or other substances before taking the medication.
- Check with your pharmacist for information on potential allergic reactions due to inactive ingredients in the product.
- Prior to using methenamine, disclose your medical history to your doctor or pharmacist, especially if you have kidney problems, liver problems, or a history of dehydration.
- Before undergoing surgery, inform your doctor or dentist about all the products you are using, including prescription drugs, nonprescription drugs, and herbal products.
- Use this medication during pregnancy only if necessary; discuss potential risks and benefits with your doctor.
- Methenamine passes into breast milk, and its impact on nursing infants is unknown; consult your doctor before breastfeeding.