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Me NaPhos MB Hyo 1 Package Insert

Updated:
Facts
Status:
Prescription (Rx)
Strength:
81.6 mg, 40.8 mg, 10.8 mg, 0.12 mg

Prescribing information (package insert) - Me NaPhos MB Hyo 1

Description

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:

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

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

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.

Breast-feeding

problems in humans have not been documented;

however, methenamine and traces of hyoscyamine are

excreted in breast milk.

Prolonged use

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

infants and young children are especially susceptible to

the toxic effect of the belladonna alkaloids.

Geriatric

use with caution in elderly patients as they may respond

to usual doses of hyoscyamine with excitement,

agitation, drowsiness, or confusion.

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.

ADVERSE REACTIONS

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

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

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

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

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).

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

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.

About this document

Source: FDA drug labeling via NLM DailyMed · View the label on DailyMed

Revision date stated in the text: January 2016

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The information on this site does not replace the advice of a doctor or pharmacist.

Drug information for Me NaPhos MB Hyo 1

Rx or OTC
Prescription (Rx)?
  • This drug is available only with a prescription from a licensed healthcare provider.
  • Rx
Drug class Oxidation-Reduction Agent
Active ingredients Methenamine 81.6 mg, Sodium phosphate, monobasic, monohydrate 40.8 mg, Methylene blue anhydrous 10.8 mg, Hyoscyamine sulfate anhydrous 0.12 mg
Dosage form Tablet
Route Oral
Marketing status listed in the FDA NDC Directory
Company (applicant) Method Pharmaceuticals
FDA approval UNAPPROVED DRUG OTHERUnapproved drug
Manufacturers 1 labelers list this drug on DailyMed
Packages (NDC)
Package
81.6 mg, 40.8 mg, 10.8 mg, 0.12 mg – 100 in 1 bottle NDC 58657-454-01

Source: FDA drug labeling via NLM DailyMed, data as of October 31, 2026. FDA data (DailyMed, Orange Book, Drug Shortages, enforcement reports). Not a substitute for the advice of a doctor or pharmacist.