Classes
DEA Class; Rx
Common Brand Names; Uroquid-Acid No. 2, Utac
- Antibiotics, Other
Description
Methenamine: Hydrolyzed in acidic urine to ammonia and formaldehyde, which are bactericidal agents; does not convert to formaldehyde in serum
Sodium acid phosphate: Urinary acidifier; elicits osmotic effect in GI tract
Indications
Use only after eradication of UTI by other appropriate antibiotic
Methenamine: Indicated for prophylaxis/suppression for chronic recurring UTIs when long-term therapy is required
Sodium salicylate: Analgesic
Benzoic acid: Elicits weak antifungal and antibacterial properties; also helps acidify urine
Contraindications
Methenamine
- Hypersensitivity to methenamine or tartrazine (FD&C Yellow No. 5)
- Renal or severe hepatic insufficiency
- Concurrent sulfonamides or acetazolamide may form insoluble precipitate in urine
Sodium acid phosphate
- Hypersensitivity
- Addison’s disease
- Hyperphosphatemia
- Acidification of urine in urinary stone disease
- Urolithiasis or struvite stone formation
- Severe renal impairment (ie, CrCl <30 mL/min)
Adverse Effects
Dysuria
Gastric upset
Nausea
Rash
Diarrhea
Nausea
Stomach pain
Vomiting
Warnings
Methenamine
- Large doses may cause bladder irritation, urinary frequency, albuminuria, and hematuria
- Maintain acidic pH of urine, especially when treating urea-splitting organisms (eg, Proteus, Pseudomonas)
- Monitor LFTs, especially with history of liver impairment
- Safe use not established during pregnancy, especially 1st and 2nd trimester
- May precipitate uric acid stones in patients with gout
Sodium acid phosphate
- History of gastrointestinal pain
- Sodium restriction
- History of kidney stones
- Risk of acute phosphate nephropathy
Pregnancy and Lactation
Pregnancy Category: C
Lactation: methenamine is excreted in human milk; caution advised, risk to infant cannot be ruled out
Maximum Dosage
Initial: 2 tablets PO q6hr with liberal fluid intake
Maintenance: 1-2 tablets PO q12hr
How supplied
Methenamine/sodium acid phosphate
tablet
- 500 mg/500 mg
