Urinary Antiseptic Antispasmodic is a prescription medicine. The sections below reproduce one FDA label for it, named under "Label". Products in other forms, strengths or from other makers have their own labels, which can differ.
- Type
- Prescription only (Rx)
- Brand names
- Me NaPhos MB Hyo 1
- Taken
- Oral
- Label
- Method Pharmaceuticals, revised October 21, 2025 · full label on DailyMed
- Generic
- No · details
What it is used for
ME/NaPhos/MB/Hyo 1 Tablets is indicated for the treatment of symptoms of irritative voiding. Indicated for the relief of local symptoms, such as hypermotility which accompany lower urinary tract infections and as antispasmodic. Indicated for the relief of urinary tract symptoms caused by diagnostic procedures.
Warnings
Do not exceed recommended dosage. If rapid pulse, dizziness, or blurring of vision occurs discontinue use immediately.
Precautions
(Pregnancy Category C) hyoscyamine and methenamine cross the placenta. Studies have not been done in animals or humans. It is not known whether ME/NaPhos/MB/Hyo 1 Tablets cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. ME/NaPhos/MB/Hyo 1 Tablets should be given to a pregnant woman only if clearly needed.
Side effects (adverse reactions)
Cardiovascula r – rapid pulse, flushing Central Nervous System – blurred vision, dizziness Respiratory – shortness of breath or troubled breathing Genitourinary – difficulty micturition, acute urinary retention Gastrointestinal – dry mouth, nausea/vomiting
Drug interactions
because of this product's effect on gastrointestinal motility and gastric emptying, it may decrease the absorption of other oral medications during concurrent use such as: urinary alkalizers; thiazide diuretics (may cause the urine to become alkaline reducing the effectiveness of methenamine by inhibiting its conversion to formaldehyde); antimuscarinics (concurrent use may intensify antimuscarinic effects of hyoscyamine because of secondary antimuscarinic activities of these medications); antacids/antidiarrheals (may reduce absorption of hyoscyamine, concurrent use with antacids may cause urine to become alkaline reducing effectiveness of methenamine by inhibiting its conversion to formaldehyde) doses of these medications should be spaced 1 hour apart from doses of hyoscyamine; antimyasthenics (concurrent use with hyoscyamine may further reduce intestinal motility); ketoconazole (patients should be advised to take this combination at least 2 hours after ketoconazole); monoamine oxidase (MAO) Inhibitors (concurrent use may intensify antimuscarinic side effects, opioid (narcotic) analgesics may result in increased risk of severe constipation); sulfonamides (these drugs may precipitate with formaldehyde in the urine, increasing the danger of crystalluria). Patients should be advised that the urine may become blue to blue green and the feces may be discolored as a result of the excretion of methylene blue.
Use in children
Pediatric infants and young children are especially susceptible to the toxic effect of the belladonna alkaloids.
Use in older adults
with caution in elderly patients as they may respond to usual doses of hyoscyamine with excitement, agitation, drowsiness, or confusion.
Is there a generic Urinary Antiseptic Antispasmodic?
No. The FDA has not approved a generic version yet.
Source: Drugs@FDA (via openFDA), checked October 29, 2026. Marketing status is what companies report to the FDA; whether a pharmacy stocks a product, and what your insurance covers, can differ.
Dosage:
we do not reproduce dosing instructions. The right dose depends on the person and the condition and is set by the prescriber or pharmacist. Dosage section of the full label.
Urinary antiseptic antispasmodic in the news
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Recalls
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Source: FDA structured product labeling, retrieved through openFDA. Label text is shown as published by the FDA, without editing; long sections are shortened, marked […]. openFDA data are not validated for clinical use — always check the current label and ask a doctor or pharmacist about your own treatment. Set ID 2ae628e7-3b33-6a9a-e054-00144ff8d46c.