Expectorants

Expectorants

Definition

Expectorants are drugs that loosen and clear mucus and phlegm from the respiratory tract.

Description

There are two drugs that are routinely used to clear mucus from the respiratory tract: guaifenesin and acetylcysteine. Guaifenesin may be taken by mouth and is an ingredient in many over-the-counter cough and cold remedies. Although acetylcysteine is by far the more reliable of the two, it must be administered with special inhalation equipment or instilled directly into the trachea.

Other drugs have been used as expectorants, but lack evidence of either efficacy or safety or both:

• ammonium chloride
• bromhexine
• ipecacuanha
• potassium iodide
• wild cherry syrup

KEY TERMS

Asthma —A disease in which the air passages of the lungs become inflamed and narrowed, causing wheezing, coughing, and shortness of breath.

Bronchitis —Inflammation of the air passages of the lungs.

Chronic —Refers to a disease or condition that progresses slowly but persists or recurs over time.

Cough suppressant —A medication that stops or prevents coughing.

Emphysema —A chronic respiratory disease that involves the destruction of air sac walls to form abnormally large air sacs that have reduced gas exchange ability and that tend to retain air within the lungs. Symptoms include labored breathing, the inability to forcefully blow air out of the lungs, and an increased susceptibility to respiratory tract infections. Emphysema is usually caused by smoking.

Mucus —The thick fluid produced by the mucous membranes that line many body cavities and structures. It contains mucin, white blood cells, water, inorganic salts, and shed cells, and it serve to lubricate body parts and to trap particles of dirt or other contaminants.

Phlegm —Thick mucus produced in the air passages.

Respiratory system —The organs that are involved in breathing: the nose, the throat, the larynx, the trachea, the bronchi and the lungs. Also called the respiratory tract.

Secretion —A substance, such as saliva or mucus, that is produced and given off by a cell or a gland.

Trachea —The windpipe. A tube composed of cartilage and membrane that extends from below the voice box into the chest where it splits into two branches, the bronchi, that lead to each lung.

These drugs, and others, are not in common use, although wild cherry syrup may be used as a flavoring agent in some liquid cough preparations. Some home remedies, including chicken soup and hot tea, may also be useful in breaking up mucus.

General use

Guaifenesin, the only medicinal product in common use as an expectorant, is an ingredient in many cough medicines, such as Anti-Tuss, Dristan Cold & Cough, Guaifed, GuaiCough, and some Robitussin products. Some products that contain guaifenesin are available only with a physician's prescription; others can be bought without a prescription. They come in several forms: capsules, tablets, and liquids. There is some dispute, even among experts, about whether guaifenesin is an effective expectorant. In some studies, it has been useful, while in others it has not shown any value. Guaifenesin should not be given to children under the age of two years unless directed by a physician.

Precautions

Guaifenesin is not meant to be used for coughs associated with asthma , emphysema, chronic bronchitis , or smoking . It also should not be used for coughs that are producing a large amount of mucus. A lingering cough could be a sign of a serious medical condition. Coughs that last more than seven days or are associated with fever , rash, sore throat , or lasting headache should have medical attention. Parents should call a physician as soon as possible.

Side effects

Side effects are rare but may include vomiting , diarrhea , stomach upset, headache, skin rash, and hives .

Interactions

Guaifenesin is not known to interact with any foods or other drugs. However, cough medicines that contain guaifenesin may contain other ingredients that do interact with foods or drugs. Parents should check with a physician or pharmacist for details about specific products.

Because the value of guaifenesin is uncertain, while the adverse effects have been documented, parents should consider using alternatives to guaifenesin-containing cough remedies for children.

Parental concerns

There is no good evidence either for or against the use of over-the-counter products for treatment of coughs. Parents may wish to avoid using cough remedies for children unless instructed to do so by a physician. Expectorants are for use only in coughs with mucus production, sometimes called productive coughs. They are of no value in coughs without mucus, sometimes called dry coughs or non-productive coughs. The recommended dosage on the product label should not be exceeded. A calibrated medicinal teaspoon, not a household teaspoon, should be used to measure any medication.

See also Cough supressants; Decongestants.

Resources

BOOKS

Mcevoy, Gerald K., et al. AHFS Drug Information 2004. Bethesda, MD: American Society of Healthsystems Pharmacists, 2004.

Siberry, George, and Robert Iannone, eds. The Harriet Lane Handbook, 15th ed. Philadelphia: Mosby, 2000.

PERIODICALS

Hopkins, Alan B. "Chicken soup cure may not be a myth." Nurse Practitioner 28, no. 6 (June 2003): 16–18.

WEB SITES

"Cough Expectorant." Family Practice Notebook. Available online at <www.fpnotebook.com/LUN116.htm> (accessed September 29, 2004).

"What's the difference between an expectorant and a cough suppressant?" Parent Center. Available online at <http://parentcenter.babycenter.com/expert/71851.html> (accessed September 29, 2004).

Nancy Ross-Flanigan Samuel Uretsky, PharmD