Methenamine + Hyoscyamine

Indications

Methenamine + Hyoscyamine is used for: Urinary Tract Irritative Voiding Symptoms

Adult Dose

Urinary Tract Irritative Voiding Symptoms 1 tablet/capsule PO q6hr with liberal fluid intake Use only after eradication of UTI by other appropriate antibiotic

Child Dose

Urinary Tract Infection Prophylaxis <16 years: Safety/efficacy not established >16 years: 1 tablet/capsule PO q6hr with liberal fluid intake Use only after eradication of UTI by other appropriate antibiotic

Renal Dose

Administration

Contra Indications

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

Precautions

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-Lactation

Pregnancy Category: C Lactation: hyoscyamine and methenamine excreted in human milk; caution in breastfeeding women

Interactions

Adverse Effects

Side effects of Methenamine + Hyoscyamine : >10% Hyoscyamine Dry skin 1-10% Methenamine Dysuria Discoloration of urine (blue) Gastric upset Nausea Rash Hyoscyamine Blurred vision Constipation Dysphagia Photosensitivity <1% Hyoscyamine Headache Orthostatic hypotension Tachycardia

Mechanism of Action

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)