Coughing is one of the most recognizable symptoms of illness. It can also be one of the most annoying. Frequent coughing can irritate the throat, make the ribs sore and even be embarrassing. Coughing related to upper respiratory tract infections is one of the most frequent reasons for ambulatory visits to health-care providers.
Opiate antitussives are narcotic agents that act centrally to suppress the cough reflex. The exact mechanism of action in unknown. This medication requires evaluation by a physician or nurse-practitioner and it does require a prescription. Hydrocodone is a semi-synthetic opiate and is considered to have the strongest effect in blocking the cough reflex. Like all narcotics, it can cause drowsiness and decrease respiratory drive. In addition, chronic use can lead to addiction. It is commonly combined with medications such as acetaminophen and homatropine to discourage overuse.
Codeine is a naturally occurring opiate alkaloid, about 10 percent of the medication is converted into morphine. It is considerably less addictive than most other opiates.
Dextromethorphan is a non-opiate antitussive medication that has been available over the counter since 1958. It does not have the side effects of sedation or respiratory suppression. Its effectiveness has been debated, and it is generally not considered effective in children. Benzonatate is a relatively effective medication that is available only with a prescription. The chemical structure is similar to local anesthetics, and it is thought to numb the cough reflex to prevent frequent coughing.
Gauifenisen is an expectorant that is believed to lubricate the airways and change the quality of the mucous. Gauifenisen is thought to produce its effect by increasing the amount of water in the bronchial secretions, making them easier to cough up.
Source: Most Effective Cough Medicines