A variety of pharmaceutical preparations are used in the treatment of coughs. The mechanisms by which cough medicines work vary according to the type of medication used. It is prudent to select cough medicines carefully, ensuring that the medication is meant to address the type of cough that the patient is experiencing. Coughs can be non-productive, meaning they do not result in the expectoration of phlegm, or they can be productive. Some coughs are due to infections; others may be caused by allergies or environmental factors such as cigarette smoke.
Increased Expectoration
Some cough medications work by breaking up mucus that is lodged in the respiratory system, allowing it to be expelled through coughing. Such medications are referred to as expectorants. The active ingredient guaifenesin is used in many expectorant medications. This ingredient has properties that thin the mucus buildup, thus facilitating its removal.
These medications are only useful in treating productive coughs. Smokers, asthmatics and those suffering from emphysema or bronchitis may benefit from the use of expectorants.
Cough Suppression
Coughs are triggered by a reflex response that causes a reaction in the brain. Antitussive medications, also known as cough suppressants, function by suppressing this cough reflex, according to FamilyDoctor.org. Dextromethorphan is the active ingredient in many popular cough suppressants, and is present in a number of popular over-the-counter formulations.
Unlike expectorants, cough suppressants are not helpful in relieving smoker's cough, asthma or obstructive pulmonary diseases such as emphysema or chronic bronchitis.
Allergy Relief
Some coughs are associated with allergies, the immune system's misguided reaction to typically benign substances that it regards as potential threats to health. Upon sensing the presence of an allergen such as pollen, the immune system of an allergic person launches an attack on the foreign substance by releasing histamines.
These naturally occurring chemicals increase blood vessel permeability and allow fluids to flood the affected tissues, leading to the runny nose and watery eyes characteristic of allergies. When an allergy is accompanied by a cough, antihistamines can treat the preexisting condition by counteracting the effects of histamine, according to the University of Maryland Medical Center.
Decongestion
Decongestants relieve coughs by clearing clogged nasal passages and easing the symptoms of postnasal drip. They are sometimes combined with antihistamines and cough suppressants to create medications designed to address cold and cough symptoms, according to FamilyDoctor.org.
