Generic
Methenamine Hippurate
3 brands available in the market
At a glance
Methenamine Hippurate is used for the prophylaxis and treatment of urinary tract infections. It acts by converting to formaldehyde in acidic urine, exhibiting bactericidal activity.
Description
Methenamine is a heterocyclic organic compound with a cage-like structure similar to adamantane. In salt form, it is used for the treatment of urinary tract infections (e.g., methenamine hippurate, the hippuric acid salt of methenamine). Its antibacterial activity is greater in acidic urine.
Indications
- Prophylaxis and treatment of urinary tract infections
- Maintenance therapy after successful initial treatment of acute infections with antibiotics
- Long-term therapy for prevention of recurrent cystitis
- Suppression of urinary infection in patients with indwelling catheters
- Prophylaxis against introduction of infection during instrumental procedures
- Asymptomatic bacteriuria
Therapeutic class
Other Genito-urinary Preparations
Pharmacological class
Urinary Antibacterial Agent
Pharmacology
Methenamine converts to formaldehyde in acidic urine, which acts as a nonspecific bactericidal agent against both gram-positive and gram-negative bacteria.
Mechanism of action
Kills bacteria by converting to formaldehyde in acidic urine.
Dosage
Adults and Children over 12 years: 1 g (1 tablet) twice daily
Children 6-12 years: 0.5-1 g (half or 1 tablet) twice daily
Administration
- Take oral tablets with water
- Restrict alkalinizing foods and medications to maintain acidic urine
- Supplemental acidification if needed
- Monitor efficacy with repeated urine cultures
Missed dose
Not generally applicable (regular use); consult doctor if needed.
Side effects
Common Side Effects (<3.5%):
- Nausea
- Vomiting
- Pruritus (rare)
- Rash (rare)
- Dysuria (rare)
Precautions & warnings
- Do not prescribe in the absence of proven or strongly suspected bacterial infection or prophylactic indication
- Maintain acidic urine when treating infections due to urea-splitting organisms (Proteus, Pseudomonas)
- Perform liver function studies periodically (especially in patients with liver dysfunction)
Contraindications
- Renal insufficiency
- Severe hepatic insufficiency
- Severe dehydration
- Do not use as sole therapeutic agent in acute parenchymal infections causing systemic symptoms
Drug interactions
No significant drug interactions known.
Food interactions
Restrict alkalinizing foods to maintain acidic urine.
Use in pregnancy
Use in Pregnancy: Methenamine may be unsafe during pregnancy (Category C); slight increase in stillborn rate and impaired weight gain in offspring observed; use only if benefits outweigh risks.
Pregnancy Category: C — always consult a doctor before taking during pregnancy.
Use in lactation
Use in Lactation: Methenamine is excreted in human milk; decide whether to discontinue nursing or the drug.
Pediatric use
Dose established for children 6-12 years (0.5-1 g twice daily).
Geriatric use
Elderly may require dose adjustment (based on renal function).
Renal / hepatic impairment
Renal Impairment: Contraindicated in renal insufficiency.
Hepatic Impairment: Contraindicated in severe hepatic insufficiency; periodic liver function studies recommended in patients with liver dysfunction.
Overdose effects
Overdose: induce vomiting or gastric lavage, activated charcoal; increase fluid intake.
Storage conditions
Store below 30°C, away from light and moisture; keep out of reach of children.
Chemical structure
Methenamine Hippurate