Dyphylline and Guaifenesin Tablets

Dyphylline is a xanthine derivative with pharmacologic actions similar to theophylline and other members of this class of drugs. Its primary action is that of bronchodilation, but it also exhibits peripheral vasodilatory and other smooth muscle relaxant activity to a lesser degree. The bronchodilatory action of dyphylline, as with other xanthines, is thought to be mediated through competitive inhibition of phosphodiesterase with a resulting increase in cyclic AMP producing relaxation of bronchial smooth muscle.

Dyphylline is well tolerated and produces less nausea than aminophylline and other alkaline theophylline compounds when administered orally. Unlike the hydrolyzable salts of theophylline, dyphylline is not converted to free theophylline in vivo. It is absorbed rapidly in therapeutically active form and in healthy volunteers reaches a mean peak plasma concentration of 17.1 mcg/mL in approximately 45 minutes following a single oral dose of 1000 mg of dyphylline.

Dyphylline exerts its bronchodilatory effects directly and, unlike theophylline, is excreted unchanged by the kidneys without being metabolized by the liver. Because of this, dyphylline pharmacokinetics and plasma levels are not influenced by various factors that affect liver function and hepatic enzyme activity, such as smoking, age, or concomitant use of drugs which affect liver function.

The elimination half-life of dyphylline is approximately two hours (1.8-2.1 hr.) and approximately 88% of a single oral dose can be recovered from the urine unchanged. The renal clearance would be correspondingly reduced in patients with impaired renal function. In anuric patients, the half-life may be increased 3 to 4 times normal.

Dyphylline plasma levels are dose-related and generally predictable. The therapeutic range of plasma levels within which dyphylline can be expected to produce effective bronchodilation has not been determined.

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 rapidly 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.

Hypersensitivity to any of the ingredients or related compounds.

This product is not indicated in the management of status asthmaticus, which is a serious medical emergency. Although the relationship between plasma levels of dyphylline and appearance of toxicity is unknown, excessive doses may be expected to be associated with an increased risk of adverse effects.

Do not use this product unless a diagnosis of asthma has been made by a doctor. Do not use this product if you have heart disease, high blood pressure, thyroid disease, diabetes, or difficulty in urination due to enlargement of the prostate gland unless directed by a doctor. Do not use this product if you have ever been hospitalized for asthma or if you are taking any prescription drug for asthma unless directed by a doctor.

General

Use Dyphylline and Guaifenesin with caution in patients with severe cardiac disease, hypertension, hyperthyroidism, acute myocardial injury or peptic ulcer. Before prescribing medication to suppress or modify cough, it is important to ascertain that the underlying cause of the cough is identified, that modification of the cough does not increase the risk of clinical or physiological complications, and that appropriate therapy for the primary disease is instituted.

Drug/Laboratory Test Interactions

Synergism between xanthine bronchodilators (e.g., theophylline), ephedrine, and other sympathomimetic bronchodilators has been reported. This should be considered whenever these agents are prescribed concomitantly. Concurrent administration of dyphylline and probenecid, which competes for tubular secretion, has been shown to increase the plasma half-life of dyphylline. Guaifenesin may increase renal clearance for urate and thereby lower serum uric acid levels. Guaifenesin may produce an increase in urinary 5- hydroxyindoleacetic acid and may therefore interfere with the interpretation of this test for the diagnosis of carcinoid syndrome. It may also falsely elevate the VMA test for catechols. Administration of this drug should be discontinued 48 hours prior to the collection of urine specimens for such tests.

Carcinogenesis, Mutagenesis, Impairment of Fertility

No long-term animal studies have been performed with this product.

Pregnancy

Animal reproduction studies have not been conducted with this formulation. It is also not known whether this product can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. This medication should be given to a pregnant woman only if clearly needed.

Nursing Mothers

Dyphylline is present in human milk at approximately twice the maternal plasma concentration. Caution should be exercised when this product is administered to a nursing woman.

Pediatric Use

This product is not indicated for use in the pediatric population.

There have been no reports, in the literature, of overdosage with this product. However, the following information based on reports of theophylline overdosage is considered typical of the xanthine class of drugs and should be kept in mind.

SIGNS AND SYMPTOMS

Restlessness, anorexia, nausea, vomiting, diarrhea, insomnia, irritability, and headache. Marked overdosage with resulting severe toxicity has produced agitation, severe vomiting, dehydration, excessive thirst, tinnitus, cardiac arrhythmias, hyperthermia, diaphoresis, and generalized clonic and tonic convulsions. Cardiovascular collapse has also occurred, with some fatalities. Seizures have occurred in some cases associated with very high theophylline plasma concentrations, without any premonitory symptoms of toxicity.

TREATMENT

There is no specific antidote for overdosage with drugs of the xanthine class. Symptomatic treatment and general supportive measures should be instituted with careful monitoring and maintenance of vital signs, fluids and electrolytes. The stomach should be emptied by inducing emesis if the patient is conscious and responsive, or by gastric lavage, taking care to protect against aspiration, especially in stuporous, or comatose patients. Maintenance of an adequate airway is essential in case oxygen or assisted respiration is needed. Sympathomimetic agents should be avoided but sedatives such as short-acting barbiturates may be useful.

Dyphylline is dialyzable and, although not recommended as routine procedure in overdosage cases, hemodialysis may be of some benefit when severe intoxication is present or when the patient has not responded to general supportive and symptomatic treatment.

Dyphylline and Guaifenesin are round, white, compressed tablets, debossed B 375. They are packaged in bottles of 100, NDC # 51991-375-01.

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.

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

STORAGE

Store at 25°C (77°F); excursions permitted to 15°-30°C (59°-86°F). See USP Controlled Room Temperature.

All prescription substitutions using this product shall be pursuant to state statutes as applicable. This is not an Orange Book product.

Distributed by: Breckenridge Pharmaceutical, Inc., Boca Raton, FL 33487

Manufactured by: Contract Pharmacal Corp., Hauppauge, NY 11788

Iss.10/03
Rev. 11/08

Made in USA