Me-NaPhos-MB-Hyo 1 Tablets

Manufacturer
Method Pharmaceuticals
Effective date
2025-10-21
Label type
HUMAN PRESCRIPTION DRUG LABEL
Version
8
Source
full-release
Hydrated at
2026-05-31 22:03:15

Label at a glance#

ProductMe NaPhos MB Hyo 1
Active ingredientMETHENAMINE, SODIUM PHOSPHATE, MONOBASIC, MONOHYDRATE, METHYLENE BLUE ANHYDROUS, HYOSCYAMINE SULFATE ANHYDROUS
Label structure19 sections

Dosage and administration

Adults One tablet orally 4 times per day followed by liberal fluid intake. Older Children Dosage must be individualized by physician. Not recommended for use in children up to 6 years of age.

Label contents#

Full prescribing information#

Description

DESCRIPTION SECTION

Each tablet contains:


Methenamine, USP ................................. 81.6 mg
Monobasic Sodium Phosphate, USP ......... 40.8 mg
Methylene Blue ....................................... 10.8 mg
Hyoscyamine Sulfate ............................... 0.12 mg

Inactive Ingredients include:

INACTIVE INGREDIENT SECTION

Microcrystalline
Cellulose, Mannitol, Croscarmellose Sodium, Magnesium
Stearate, FD&C Blue #1


HYOSCYAMINE SULFATE is an alkaloid of belladonna.
Exists as a white crystalline powder. Affected by light It
is very soluble in water; freely soluble in alcohol;
practically insoluble in ether.
METHENAMINE exists as colorless, lustrous crystals or
white crystalline powder. Its solutions are alkaline to
litmus. Freely soluble in water; soluble in alcohol and in
chloroform.


METHYLENE BLUE exists as dark green crystals. It is
soluble in water and in chloroform; sparingly soluble in
alcohol.


MONOBASIC SODIUM PHOSPHATE exists as a white
crystalline powder. Its solutions are acidic to litmus. It is
freely soluble in water and practically insoluble in
alcohol.


This product is not an Orange Book (OB) rated
product, therefore all prescriptions using this
product shall be pursuant to state statutes as
applicable. There are no claims of bioequivalence
or therapeutic equivalence.

CLINICAL PHARMACOLOGY

CLINICAL PHARMACOLOGY SECTION

HYOSCYAMINE is a parasympatholytic which relaxes
smooth muscles and thus produces an antispasmodic
effect. It is well absorbed from the gastrointestinal tract
and is rapidly distributed throughout body tissues. Most
is excreted in the urine within 12 hours, 13% to 50%
being unchanged.


Its biotransformation is hepatic. Its protein binding is
moderate.


METHENAMINE degrades in an acidic urine environment
releasing formaldehyde which provides bactericidal or
bacteriostatic action. It is well absorbed from the
gastrointestinal tract. 70% to 90% reaches the urine
unchanged at which point it is hydrolyzed if the urine is
acidic. Within 24 hours it is almost completely (90%)
excreted; of this amount at pH 5, approximately 20% is
formaldehyde. Protein binding: some formaldehyde is
bound to substances in the urine and surrounding
tissues. Methenamine is freely distributed to body tissue
and fluids but is not clinically significant as it does not
hydrolyze at pH greater than 6.8.


METHYLENE BLUE possesses weak antiseptic properties.
It is well absorbed in the gastrointestinal tract and is
rapidly reduced to leukomethylene blue which is
stabilized in some combination form in the urine. 75%
is excreted unchanged.


MONOBASIC SODIUM PHOSPHATE helps to maintain an
acid pH in the urine necessary for the degradation of
methenamine.

INDICATION AND USAGE

INDICATIONS & USAGE SECTION

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

WARNINGS SECTION

Do not exceed recommended dosage. If rapid pulse,
dizziness, or blurring of vision occurs discontinue use
immediately.

PRECAUTIONS

PRECAUTIONS SECTION

(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.

Breast-feeding

SPL UNCLASSIFIED SECTION

problems in humans have not been documented;
however, methenamine and traces of hyoscyamine are
excreted in breast milk.

Prolonged use

SPL UNCLASSIFIED SECTION

there have been no studies to establish the safety of
prolonged use in humans. No known long-term animal
studies have been performed to evaluate carcinogenic
potential.

Pediatric

PEDIATRIC USE SECTION

infants and young children are especially susceptible to
the toxic effect of the belladonna alkaloids.

Geriatric

GERIATRIC USE SECTION

use with caution in elderly patients as they may respond
to usual doses of hyoscyamine with excitement,
agitation, drowsiness, or confusion.

Drug Interactions

DRUG INTERACTIONS SECTION

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.

ADVERSE REACTIONS

ADVERSE REACTIONS SECTION

Cardiovascular – 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 ABUSE AND DEPENDENCE

DRUG ABUSE AND DEPENDENCE SECTION

A dependence on the use of ME/NaPhos/MB/Hyo 1
Tablets has not been reported and due to the nature of
its ingredients, abuse of ME/NaPhos/MB/Hyo 1
Tablets
is not expected.

OVERDOSAGE

OVERDOSAGE SECTION

Emesis or gastric lavage. Slow intravenous
administration of physostigmine in doses of 1 mg to
4 mg (0.5 mg to 1 mg in children), repeated as needed
in one to two hours to reverse severe antimuscarinic
symptoms. Administration of small doses of diazepam to
control excitement and seizures. Artificial respiration
with oxygen if needed for respiratory depression.
Adequate hydration. Symptomatic treatment as
necessary.

DOSAGE AND ADMINISTRATION

DOSAGE & ADMINISTRATION SECTION

Adults


One tablet orally 4 times per day followed by liberal
fluid intake.


Older Children


Dosage must be individualized by physician. Not
recommended for use in children up to 6 years of age.

HOW SUPPLIED

HOW SUPPLIED SECTION

ME/NaPhos/MB/Hyo 1 Tablets are light blue to
blue, oval, biconvex tablets debossed with
"M455" with scoreline on one side and plain on
the other side. Supplied in bottles of 100 tablets
(NDC 58657-454-01).

OTHER SAFETY INFORMATION

CAUTION


RX ONLY


STORAGE


Store at 25° C (77° F); excursions permitted to 15° C to
30° C (59° F to 86° F) [See USP Controlled
Room Temperature]. Keep container tightly closed.


Distributed By: Method Pharmaceuticals, LLC
Arlington, TX 76006


Rev. Date: 01/2016

GENERAL PRECAUTIONS SECTION

DIRECTIONS: 1 Tablet 4 times daily followed by liberal fluid intake, or
as directed by a physician.


FOR FULL PRODUCT INFORMATION SEE ATTACHED BOOKLET.
Store at 25° C (77° F); excursions permitted to 15° C to 30° C (59° F to
86° F) [See USP Controlled Room Temperature]. Protect from moisture or
direct sunlight.


NOTE: Patient should be advised that urine will be colored blue while
taking this medication.


PHARMACIST: Preserve and dispense in tight-light resistant container as
defined in the USP.

KEEP THIS AND ALL MEDICINES OUT OF THE REACH OF

CHILDREN.

Tamper evident by heat seal under cap. Do not use if there is
evidence of tampering.

To report an adverse event, please contact Method
Pharmaceuticals, LLC at (877) 250-3427.

PACKAGE LABEL.PRINCIPAL DISPLAY PANEL

Distributed by: Method Pharmaceuticals, LLC
Arlington, TX 76006 Rev. Date: 01/2016

Pinciple Display Panel

lablab

Booklet

bookletbooklet

DailyMed RxNorm Mappings#

RxCUI, RxNorm string, TTY table
RxCUIRxNorm stringTTYSPL version
1050325methenamine 81.6 MG / sodium phosphate, monobasic 40.8 MG / methylene blue 10.8 MG / hyoscyamine sulfate 0.12 MG Oral TabletPSN8
1050325hyoscyamine sulfate 0.12 MG / methenamine 81.6 MG / methylene blue 10.8 MG / sodium phosphate, monobasic 40.8 MG Oral TabletSCD8

DailyMed Pharmacologic Classes#

Class, Version, Type table
ClassVersionTypeEffective
METHYLENE BLUE CATION Pharmacologic Class Indexing2Indexing - Pharmacologic Class20180813

DailyMed Product Concepts#

Product concept, Relation, Version table
Product conceptRelationVersionEffective
260b0da6-d3d7-262f-a60f-d4b36d5f1b4dProduct name620251210
c39b72c3-7732-4ed2-a995-e6aa3a665a54Product name320250819
efd58dcf-540a-4531-8766-e713129ca6f2Product name120250307
4b7700e3-6e0e-45e5-9d22-6f754d61386eProduct name220250304
726062af-1135-4707-a1d7-57256991bbf9Product name220250226
7cda52fc-125f-421c-8fea-bc1974370c49Product name220180703
0ca1d589-929b-4b33-bc5b-1d84abdafa6aProduct name120150324
fc363c46-397b-4476-ac0f-70e43e8e4592Product name120150324
19c71a3d-ed9c-166b-a7e5-38c250c35631Product name120140508

DailyMed Package Descriptions#

Package NDC, Product, Description table
Package NDCProductDescriptionFormQuantityStrengthSPL version
58657-454-01Me NaPhos MB Hyo 1100 in 1 BOTTLETABLET1008

DailyMed Billing Units#

Package NDC, Billing unit, Product NDC table
Package NDCBilling unitProduct NDCDailyMed indexing SPLSPL versionEffective
58657-454-01EA - Each58657-4547dd0001b-b6ff-4b89-bc43-ecccda4e624712016-03-04

Products#

Every source-derived product name is available through these pages.

DailyMed product names page 1 of 1 · 13 matching rows.

NDC Codes#

Product NDC, Package NDC table
Product NDCPackage NDC
58657-45458657-454-01

Ingredients#

Every source-derived ingredient row is available through these pages.

DailyMed ingredient rows page 1 of 1 · 8 matching rows.

Source Document#

Source XML

Older Hydrated Versions#

Version, Effective date, Source table
VersionEffective dateSourceHydrated
72024-11-20full-release2026-05-31 21:18:02

openFDA label cross-check#

OpenFDA label data provides additional search and identifier links. DailyMed’s Structured Product Label is the canonical label on FDA.report. Matching records are deduplicated before they are shown below.

Matched openFDA labels page 1 of 1 · 1 matching rows.

Brand, Generic, Manufacturer table
BrandGenericManufacturerSPL set IDEffective dateAvailable safety fieldsJoin
Me NaPhos MB Hyo 1URINARY ANTISEPTIC ANTISPASMODICMethod Pharmaceuticals2ae628e7-3b33-6a9a-e054-00144ff8d46c2025-10-21Warnings, Adverse reactionsExact identifier
ndc (package): 58657-454-01
ndc (product): 58657-454
ndc11 (package): 58657045401
spl id: 41b576a1-2a59-9f3c-e063-6394a90aec7d
spl set id: 2ae628e7-3b33-6a9a-e054-00144ff8d46c

Reported adverse events (FAERS/openFDA)#

Adverse event summaries are temporarily unavailable. Other product information remains available.