Each Entex LA orange, scored, long-acting tablet for oral administration contains

phenylpropanolamine hydrochloride ...................... 75 mg

guaifenesin ......................................................... 400 mg

in a special base to provide a prolonged therapeutic effect.

This product contains ingredients of the following therapeutic classes: decongestant and expectorant.

Phenylpropanolamine hydrochloride is a decongestant having the chemical name, benzenemethanol, (alpha)-(1-aminoethyl)-, hydrochloride (R*, S*), (±), with the following structure:


Guaifenesin is an expectorant having the chemical name, 1,2-propanediol, 3-(2-methoxyphenoxy)-, with the following structure:


Inactive Ingredients: Each tablet contains carbomer 934 P, compressible sugar, docusate sodium, FD&C Yellow No. 6 Aluminum Lake, hydroxypropyl cellulose, hydroxypropyl methylcellulose, polyethylene glycol, silicon dioxide, stearic acid, titanium dioxide, and zinc stearate.

Phenylpropanolamine hydrochloride is an (alpha)-adrenergic receptor agonist (sympathomimetic) which produces vasoconstriction by stimulating (alpha)-receptors within the mucosa of the respiratory tract. Clinically, phenylpropanolamine shrinks swollen mucous membranes, reduces tissue hyperemia, edema, and nasal congestion, and increases nasal airway patency. Guaifenesin promotes lower respiratory tract drainage by thinning bronchial secretions, lubricates irritated respiratory tract membranes through increased mucous flow, and facilitates removal of viscous, inspissated mucus. As a result of these drugs, sinus and bronchial drainage is improved, and dry, nonproductive coughs become more productive and less frequent.

Entex LA is indicated for the symptomatic relief of sinusitis, bronchitis, pharyngitis, and coryza when these conditions are associated with nasal congestion and viscous mucus in the lower respiratory tract.


Entex LA is contraindicated in individuals with known hypersensitivity to sympathomimetics, severe hypertension, or in patients receiving monoamine oxidase inhibitors.

Sympathomimetic amines should be used with caution in patients with hypertension, diabetes mellitus, heart disease, peripheral vascular disease, increased intraocular pressure, hyperthyroidism, or prostatic hypertrophy.


Information for Patients: Do not crush or chew Entex LA tablets prior to swallowing.

Drug Interactions:   Entex LA should not be used in patients taking monoamine oxidase inhibitors or other sympathomimetics.

Drug/Laboratory Test Interactions:   Guaifenesin has been reported to interfere with clinical laboratory determinations of urinary 5-hydroxyindoleacetic acid (5-HIAA) and urinary vanillylmandelic acid (VMA).

Pregnancy    Pregnancy Category C. Animal reproduction studies have not been conducted with Entex LA . It is also not known whether Entex LA can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Entex LA should be given to a pregnant woman only if clearly needed.

Nursing Mothers:   It is not known whether the drugs in Entex LA are excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants, a decision should be made whether to discontinue nursing or to discontinue the product, taking into account the importance of the drug to the mother.

Pediatric Use:   Safety and effectiveness of Entex LA tablets in pediatric patients below the age of 6 have not been established.


Possible adverse reactions include nervousness, insomnia, restlessness, headache, nausea, or gastric irritation. These reactions seldom, if ever, require discontinuation of therapy. Urinary retention may occur in patients with prostatic hypertrophy.


The treatment of overdosage should provide symptomatic and supportive care. If the amount ingested is considered dangerous or excessive, induce vomiting with ipecac syrup unless the patient is convulsing, comatose, or has lost the gag reflex, in which case perform gastric lavage using a large-bore tube. If indicated, follow with activated charcoal and a saline cathartic. Since the effects of Entex LA may last up to 12 hours, treatment should be continued for at least that length of time.


Adults and adolescents 12 years of age and older: one tablet twice daily (every 12 hours).

Children 6 to under 12 years: one-half ( 1 / 2 ) tablet twice daily (every 12 hours). Entex LA is not recommended for pediatric patients under 6 years of age.

Tablets may be broken in half for ease of administration without affecting release of medication but should not be crushed or chewed prior to swallowing.


Entex LA is available as an orange, scored tablet coded with "ENTEX LA" on one side and "033 033" on the scored side.

NDC 51479-033-01 bottles of 100

NDC 51479-033-05 bottles of 500

Dispense in tight, light-resistant containers as defined in USP.

Store below 77°F (25°C).

Rx only.

Manufactured by

WelPharm, Inc.

Irvine, CA 92614

Manufactured for

DURA Pharmaceuticals, Inc.

San Diego, CA 92121

REVISED June, 1998                                 ELA 004C98