Methenamine Hippurate

Generic Details

Generic Name

Methenamine Hippurate

Other Names

  • Hiprex
  • Urex

Drug Class

  • Urinary Anti-Infectives

Chemical Formula

C13H16N4O5.C9H8O3

Molecular Weight

438.42 g/mol

Mechanism of Action

  • Converts to formaldehyde in an acidic environment, which has antibacterial properties.

Indications

  • Urinary tract infections (UTIs) caused by susceptible bacteria.

Common Dosage Forms

  • Tablet

Typical Dosage

  • 1 g twice daily

Pediatric Dosage

  • Not established for all indications

Geriatric Dosage

  • May require dosage adjustment based on renal function

Side Effects

  • Gastrointestinal upset
  • Skin rash
  • Photosensitivity

Contraindications

  • Severe renal impairment
  • Hepatic dysfunction
  • Hypersensitivity to the drug

Pregnancy Category

  • Category B - Animal reproduction studies have failed to demonstrate a risk to the fetus.

Lactation Safety

  • Compatible with breastfeeding

Drug Interactions

  • Avoid concurrent use with sulfa-containing medications.

Overdose Symptoms

  • Severe abdominal pain
  • Nausea
  • Vomiting

Antidote for Overdose

  • Treatment is symptomatic and supportive.

Storage Conditions

  • Store at room temperature away from moisture and heat.

Pharmacokinetics

  • Absorption: Well-absorbed from the gastrointestinal tract
  • Distribution: Distributed widely in body tissues
  • Metabolism: Metabolized in the liver to formaldehyde and hippuric acid
  • Excretion: Excreted primarily in the urine

Precautions

  • Monitor renal function during therapy
  • Use with caution in patients with hepatic impairment.

Warnings

  • May cause crystalluria, adequate fluid intake is recommended to prevent this.

Others

  • May be used for long-term prophylaxis of recurrent UTIs.