Classes
DEA Class; Rx
Common Brand Names; Prosed DS, Darpaz, Urogesic Blue
- Antibiotics, Other
Description
Methenamine: Hydrolyzed in acidic urine to ammonia and formaldehyde, which are bactericidal agents; does not convert to formaldehyde in serum
Hyoscyamine: Elicits anticholinergic activity; decreases urinary spasms with cystitis
Additional ingredients in some products: Methylene blue (weak antiseptic properties); sodium phosphate monobasic (acidifier); phenyl salicylate (mild analgesic)
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
Hyoscyamine: Adjunctive treatment for lower urinary tract hypermotility and spasm
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
Hyoscyamine
Hypersensitivity to hyoscyamine or related compounds
Closed-angle glaucoma, myasthenia gravis, hemorrhage w/ cardiovascular instability, paralytic ileus, intestinal atony of elderly/debilitated pt, obstructive uropathy, toxic megacolon, GI obstruction, tachycardia secondary to cardiac insufficiency or thyrotoxicosis
Breastfeeding
Adverse Effects
- Dry skin
- Dysuria
- Discoloration of urine (blue)
- Gastric upset
- Nausea
- Rash
- Blurred vision
- Constipation
- Dysphagia
- Photosensitivity
Warnings
Methenamine
Large doses may cause bladder irritation, urinary frequency, albuminuria, and hematuria
Maintain acidic pH of urine, esp. 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
Hyoscyamine
Renal/hepatic impairment, BPH, CHF, CAD, HTN, COPD, hiatal hernia, reflux esophagitis, mitral stenosis, brain damage or spastic paralysis in children, salivary secretion disorder, Down syndrome, autonomic neuropathy, hyperthyroidism, tachyarrythmia, toxin-mediated diarrhea
Elderly
Pregnancy and Lactation
Pregnancy Category: C
Lactation: hyoscyamine and methenamine excreted in human milk; caution in breastfeeding women
Maximum Dosage
Adult
1 tablet/capsule PO q6hr with liberal fluid intake
Pediatric
<16 years: Safety/efficacy not established
≥16 years: 1 tablet/capsule PO q6hr with liberal fluid intake
Geriatric
Avoid hyoscyamine except in short-term situations to decrease secretions; high incidence of anticholinergic effects (Beers criteria)