Coughing is a protective reflex that is induced automatically by the human body when it detects some form of irritant in the lower and upper airways. Coughs usually fall into two categories: The dry, irritating kind and those that produce a lot of phlegm and mucus.
The two different types of coughs
A dry cough is usually experienced after a person has recovered from an infection and the irritation and inflammation remain, or it can be caused by an allergy. It is generally not a productive, or wet cough, where phlegm and mucus is produced. The use of a cough suppressant, or antitussive, is usually indicated in the presence of a dry cough.
Cough suppressants should not be used for a wet cough. In this situation, it is best that the mucus and phlegm are loosened so that they are more easily coughed up and cleared from the lungs. Cough mixtures, called expectorants, are usually prescribed for this sort of cough.
How a cough suppressant works
Whilst it is a necessary defense mechanism to protect the airways, constant coughing can become exhausting and painful. The abdominal and chest muscles contract continually to expel air from the lungs and the throat is irritated by the constant, harsh expulsion of air. An untreated cough will also cause constant irritation, which leads to increased inflammation which causes further irritation. The result is a vicious circle of inflammation-induced irritation which produces an ongoing cough. In order to stop this cycle and allow the airways to recover, it is necessary to suppress or dampen the cough reflex.
Codeine, a derivative of opium, is a pain-relieving drug that is usually used to treat moderate pain or diarrhea. However, it is also useful in the suppression of the cough reflex, as it acts on the area of the brain which controls the cough mechanism. It dulls the neural pathways that stimulate the contraction of muscles in the abdomen and chest.
The composition of a prescription cough medicine
Prescription cough medicine used for the suppression of coughs contains codeine in the form of hydrocodone. It is combined with other drugs in the formulation of the cough medicine, depending on the particular effect required. The two most common combinations are hydrocodone with homatropine and hydrocodone with chlorpheniramine.
Cough medicines containing the hydrocodone/homatropine combination include Hycodan, Hydromet, Tussigon and Mycodone. Homatropine belongs to a class of drugs known as anticholinergics which help to dry up mucus secretions.
Tussionex Penkinnetic and Tussigon contain hydrocodone in combination with chlorpheniramine. Chlorpheniramine is an antihistamine which helps to alleviate inflammation and irritation in coughs that are caused by allergies.
Prescription cough medicine vs. over-the-counter (OTC) medicine
Most pharmacies stock a number of OTC cough medications which are available without a prescription, but these tend to be less effective for more serious coughs. A persistent cough should also not be left untreated for too long a period of time, as antibiotics may also be required to get rid of any infection that might be present. If a cough persists for more than 10 days, it is advisable to visit a doctor so that a proper diagnosis can be made and a more suitable prescription cough medicine provided.