Details About Generic Salt ::  Methenam

Main Medicine Class:: Urinary anti-infective   

(meh-THEN-uh-meen and meh-THEN-uh-meen salts)
Methenamine Hippurate
Hiprex, Urex
Mandameth, Mandelamine
Class: Urinary anti-infective


Drugs Class ::

 Action In acidic urine, methenamine is hydrolyzed to ammonia and formaldehyde, which is bactericidal to certain bacteria in urine. Acid salts (methenamine mandelate and hippurate) have some nonspecific bacteriostatic activity and help to maintain low urine pH.

Indications for Drugs ::

 Indications Suppression or elimination of bacteriuria associated with pyelonephritis, cystitis and other chronic urinary tract infections; treatment of infected residual urine, sometimes accompanying neurologic disease or diabetes.

Drug Dose ::


Methenamine Hippurate

ADULTS & CHILDREN > 12 YR: PO 1 g bid. CHILDREN 6–12 YR: PO 500 mg-1 g bid.

Methenamine Mandelate

ADULTS: PO 1 g qid after meals and at bedtime. CHILDREN 6–12 YR: PO 500 mg qid. CHILDREN < 6 YR: PO 250 mg for q 30 lb body weight qid (18.4 mg/kg qid).

Contraindication ::

 Contraindications Renal insufficiency; severe dehydration; severe hepatic insufficiency with hyperammonemia; acute urinary tract infections involving renal parenchyma.

Drug Precautions ::


Pregnancy: Category C. Lactation: Undetermined. Debilitated patients and patients with swallowing difficulty: Use with caution to avoid inducing lipoid pneumonia. Acid urine: If acidification of urine cannot be obtained or is contraindicated, drug is not recommended. Gout: May cause precipitation of urate crystals in urine. Lipoid pneumonia: Methenamine mandelate oral suspension is vegetable oil–based; spiration could result in lipoid pneumonitis. Tartrazine sensitivity: Some products contain tartrazine, which may cause rash or bronchial asthma in susceptible patients.


Drug Side Effects ::

 Adverse Reactions

CNS: Headache. DERM: Pruritus; urticaria; erythematous eruptions; rash. GI: Nausea; vomiting; cramps; diarrhea; stomatitis; anorexia. GU: Bladder irritation; dysuria; proteinuria; hematuria; frequency; urgency; rystalluria. HEMA: Serum transaminase elevation. RESP: Dyspnea. OTHER: Generalized edema.

Drug Mode of Action ::  

 Action In acidic urine, methenamine is hydrolyzed to ammonia and formaldehyde, which is bactericidal to certain bacteria in urine. Acid salts (methenamine mandelate and hippurate) have some nonspecific bacteriostatic activity and help to maintain low urine pH.

Drug Interactions ::


Sulfonamides: May increase chance of crystalluria. Urine alkalizers (acetazolamide, sodium bicarbonate or carbonate): Prevents hydrolysis of methenamine to formaldehyde with possible decrease in antimicrobial action.

Drug Assesment ::


  • Obtain patient history, including drug history and any known allergies.
  • Obtain clean-catch urine specimen for culture and sensitivity before beginning therapy.
  • Monitor I&O, and watch for bladder irritation (painful/frequent urination, proteinuria, hematuria); dose may need to be decreased if these symptoms occur. Fluid intake should be maintained at 1500–2000 ml/day (if medically acceptable).
  • Monitor liver function test results for transient increase in enzymes.
  • Avoid concurrent use of sulfonamides (may cause precipitates), or any drugs that will alkalize urine.

Drug Storage/Management ::


  • Administer after meals and at bedtime to minimize GI distress.
  • Reconstitute granules by dissolving 1 packet (500 mg-1 g) in 60–120 ml of water immediately before use. Solution may be cloudy.
  • Urinary acidification using ascorbic acid to maintain low pH may be necessary.
  • Store at room temperature in tightly closed container. Protect from excessive heat.

Drug Notes ::

 Patient/Family Education

  • Explain significance of adequate hydration.
  • Tell patient to report these symptoms to physician: painful urination, skin rash, headache, swelling or severe stomach upset.
  • Instruct patient to avoid use of milk products and antacids while taking drug to help keep urine acidic and allow drug to work better. Instruct patient to take vitamin C and drink cranberry or prune juice to acidify urine.
  • Caution patient not to self-medicate with otc medications containing sodium bicarbonate or sodium carbonate.
  • Teach patient how to read dipstick tests for urine pH and specific gravity and to report to physician if required values are not attained.

Disclaimer ::

The Information available on this site is for only Informational Purpose , before any use of this information please consult your Doctor .Price of the drugs indicated above may not match to real price due to many possible reasons may , including local taxes etc.. These are only approximate indicative prices of the drug.


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