methenamine/hyoscyamine (Discontinued)

Brand and Other Names:Prosed DS, Darpaz, more...Urogesic Blue
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Dosing & Uses

AdultPediatricGeriatric

Dosage Forms & Strengths

methenamine/hyoscyamine

tablet

  • 81mg/0.12mg

tablet, capsule

  • 120mg/0.12mg

Urinary Tract Irritative Voiding Symptoms

1 tablet/capsule PO q6hr with liberal fluid intake

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

Dosage Forms & Strengths

tablet

  • 81 mg/0.12mg

tablet, capsule

  • 120 mg/0.12mg

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

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

Avoid hyoscyamine except in short-term situations to decrease secretions; high incidence of anticholinergic effects (Beers criteria)

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Interactions

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and methenamine/hyoscyamine

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            Adverse Effects

            >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
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            Warnings

            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

            Cautions

            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
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            Pregnancy & Lactation

            Pregnancy Category: C

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

            Pregnancy Categories

            A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA: Information not available.

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            Pharmacology

            Mechanism of Action

            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)

            Absorption

            Well absorbed; 10-30% hydrolyzed by gastric acid unless enteric coated tablet

            Peak Urine Time: (formaldehyde) 2 hr for hippurate salt, 3-8 hr for mandelate salt

            Metabolism

            Liver (10-25%)

            Elimination

            Half-Life: 3-6 hr

            Excretion: urine (90%)

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            Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.