通用名：盐酸伪麻黄碱，愈创木酚甘油醚
剂型：片剂
每片含：
伪麻黄碱盐酸........................ 60毫克
愈创甘油醚....................................... 400毫克
Exefen IR片的剂量和给药方法
成人和12岁以上儿童：1片口，每4-6小时，在24小时内不得超过4片。儿童6〜12岁：1/2片口，每4-6小时不超过2片，在24小时内。

Exefen IR Tablets
Generic Name: pseudoephedrine hydrochloride and guaifenesin
Dosage Form: tablet

Tablets
Rx Only

Exefen IR Tablets Description
Each immediate-release tablet for oral administration contains:

Pseudoephedrine HCl    60 mg
Guaifenesin    400 mg

Inactive ingredients
Croscarmellose Sodium, Magnesium Stearate, Maltodextrin, Microcrystalline Cellulose, Polyvinylpyrrolidone, Silica and Stearic Acid.

Pseudoephedrine hydrochloride is an adrenergic (vasoconstrictor) which occurs as fine, white to off white crystals or powder, having a faint characteristic odor. It is very soluble in water, freely soluble in alcohol and sparingly soluble in chloroform. The chemical name is benzenemethanol, α - [1-(methylamino) ethyl]-, [S-(R*,R*)]-, hydrochloride. The structural formula is:

Guaifenesin is an expectorant and occurs as a white to slightly gray, crystalline powder, having a bitter taste. It may have a slight characteristic odor. It is soluble in water, in alcohol, in chloroform, in glycerin and in propylene glycol. The chemical name is: 1,2 propanediol, 3-(2-methoxyphenoxy)-. Chemically, Guaifenesin is 1,2-Propanediol, 3-(2-methoxyphenoxy)-,(+) and has the following structural formula:

Exefen IR Tablets - Clinical Pharmacology
Pseudoephedrine
Pseudoephedrine acts as an indirect sympathomimetic agent by stimulating sympathetic (adrenergic) nerve endings to release norepinephrine. Norepinephrine in turn stimulates alpha and beta receptors throughout the body. The action of pseudoephedrine is apparently more specific for the blood vessels of the upper respiratory tract and less specific for the blood vessels of the systemic circulation.The vasoconstriction elicited at these sites results in the shrinkage of swollen tissues in the sinuses and nasal passages. Pseudoephedrine is rapidly and almost completely absorbed from the gastrointestinal tract. Considerable variation in half-life has been observed ( from about 4 1/2 to 10 hours), which is attributed to individual differences in absorption and excretion. Excretion rates are also altered by urine pH, increasing with acidification and decreasing with alkalinization. As a result, mean half-life falls to about 4 hours at pH 5 and increases to 12 to 13 hours at pH 8.

After administration of a 60 mg tablet, 87 to 96% of the Pseudoephedrine is cleared from the body within 24 hours. The drug is distributed to body tissues and fluids, including fetal tissue, breast milk, and the central nervous system (CNS). About 55 to 75% of an administered dose is excreted unchanged in the urine; the remainder is apparently metabolized in the liver to inactive compounds by Ndemethylation, parahydroxylation and oxidative deamination.

Guaifenesin
Guaifenesin is an expectorant which increases respiratory tract fluid secretions and helps to loosen phlegm and bronchial secretions. By reducing the viscosity of secretions, Guaifenesin increases the efficiency of the cough reflex and of ciliary action in removing accumulated secretions from the trachea and bronchi. Guaifenesin is readily absorbed from the gastrointestinal tract and is readily metabolized and excreted in the urine. Guaifenesin has a plasma half-life of one hour. The major urinary metabolite is β -(2-methoxyphenoxy) lactic acid.

Overdosage
Overdosage with pseudoephedrine can cause excessive CNS stimulation resulting in excitement, nervousness, anxiety, tremor, restlessness, and insomnia. Other effects include tachycardia, hypertension, pallor, mydriasis, hyperglycemia and urinary retention. Severe overdosage may cause tachypnea or hyperpnea, hallucinations, convulsions or delirium, but in some individuals there may be CNS depression with somnolence, stupor or respiratory depression. Arrhythmias (including ventricular fibrillation) may lead to hypotension and circulatory collapse. Severe hypokalemia can occur, probably due to compartmental shift rather than depletion of potassium. No organ damage or significant metabolic derangement is associated with Pseudoephedrine overdosage.

The LD50 (single, oral dose) of Pseudoephedrine is 726 mg/kg in the mouse, 2206 mg/kg in the rat and 1177 mg/kg in the rabbit. The toxic and lethal concentrations in human biologic fluids are not known. Excretion rates increase with urine acidification and decrease with alkalinization. Few reports of toxicity due to pseudoephedrine have been published and no case of fatal overdosage is known.

Treatment
The patient should be induced to vomit, even if emesis has occurred spontaneously; however, vomiting should not be induced in patients with impaired consciousness. Precautions against aspiration should be taken, especially in infants and children.

Ipecac syrup is the preferred method for inducing vomiting. The action of ipecac syrup is facilitated by physical activity and the administration of eight to twelve fluid ounces of water. If emesis does not occur in fifteen minutes, the dose of ipecac should be repeated. Following emesis, any drug remaining in the stomach may be absorbed by activated charcoal administered as a slurry with water.

If vomiting is unsuccessful or contraindicated, gastric lavage should be performed. Isotonic and one-half isotonic saline are the lavage solutions of choice. Saline cathartics, such as milk of magnesia, draw water into the bowel by osmosis and, therefore, may be valuable for their action of rapid dilution of bowel content.

Treatment of the signs and symptoms of overdosage is symptomatic and supportive. Vasopressors maybe used to treat hypotension. Short- acting barbiturates, diazepam or paraldehyde maybe administered to control seizures. Hyperpyrexia, especially in children, may require treatment with tepid water sponge baths or a hypothermic blanket. Apnea is treated with ventilatory support. Stimulants (analeptic agents) should not be used.

Guaifenesin
Overdosage with Guaifenesin is unlikely to produce toxic effects since its toxicity is low. Guaifenesin, when administered by stomach tube to test animals in doses up to 5 grams/kg, produced no signs of toxicity. In severe cases of overdosage, treatment should be aimed at reducing further absorption of the drug. Gastric emptying (Syrup of Ipecac) and/or lavage is recommended as soon as possible after ingestion.

Exefen IR Tablets Dosage and Administration
Adults and Children over 12 years of age: 1 tablet by mouth every 4-6 hours not to exceed 4 tablets in 24 hours. Children 6 to under 12 years: 1/2 tablet by mouth every 4-6 hours not to exceed 2 tablets in 24 hours.

How is Exefen IR Tablets Supplied
EXEFEN-IR Tablets are supplied as white, oval- shaped tablets, debossed "LL 154"; in bottles of 100 Tablets. NDC 68047-154-01

Dispense in a tight, light-resistant container with a child-resistant closure as defined in the USP/NF.

Protect from light and moisture. Store at room temperature, USP.

WARNING: KEEP THIS AND ALL MEDICATIONS OUT OF THE REACH OF CHILDREN. IN CASE OF ACCIDENTAL OVERDOSE, SEEK PROFESSIONAL ASSISTANCE OR CONTACT A POISON CONTROL CENTER IMMEDIATELY.

Rx Only

Report Adverse Reactions to:
Distributed by:

LARKEN
LABORATORIES

Manufactured by:

Contract Pharmacal Corp.
PRINCIPAL DISPLAY PANEL - 100 Tablet Bottle Label

EXEFEN - IR

DECONGESTANT - EXPECTORANT

IMMEDIATE- RELEASE TABLETS

Each Tablet Contains:
Pseudoephedrine HCl ........................60mg
Guaifenesin .......................................400mg

Rx Only
100 Tablets