What cough medications are available?
Antitussives are drugs that suppress a cough. Narcotics--primarily codeine--are used as antitussives and work by depressing the cough center in the brain. However, they can cause such side effects as drowsiness, nausea, and constipation. Dextromethorphan, the primary ingredient in many over-the-counter cough remedies, also depresses the brain's cough center, but without the side effects associated with narcotics. Demulcents relieve coughing by coating irritated
passageways. Dextromethorphan, a congener of the narcotic analgesic levorphanol, has no significant analgesic or sedative properties, does not depress respiration in usual doses, and is nonaddictive. Codeine, which has antitussive, analgesic, and slight sedative effects, is especially useful in relieving painful cough. Demulcents are useful for coughs originating above the larynx. They form a protective coating over the irritated pharyngeal mucosa. Local anesthetics (eg, lidocaine, benzocaine, hexylcaine hydrochloride, and tetracaine) are used to inhibit the cough reflex under special circumstances (eg, before bronchoscopy or bronchography). Humidifying aerosols and steam inhalations exert an antitussive effect by acting as a demulcent and by decreasing the viscosity of bronchial secretions.
Expectorants are drugs that make mucus easier to cough up by thinning it. Guaifenesin and terpin hydrate are the primary ingredients in most over-the-counter expectorants. These drugs are intended to help expel bronchial secretions from the respiratory tract by decreasing their viscosity, thus facilitating removal, and by increasing the amount of respiratory tract fluid, thus exerting a demulcent action on the mucosal lining.
Cough suppressants like dextromethorphan (Vicks 44, Robitussin DM) may lessen your cough. Although coughing can be a troubling symptom, it is usually your body's way of healing the underlying condition. Therefore, you may not want to supress a cough unless it is interfering with sleep or other factors important for healing. Centrally acting suppressants include DXM (dextromethorphan), noscapine, ethyl morphine, and codeine. Peripherally acting substances include local anaesthetics that reduce sensation of the nerves of the throat, and demulcents that coat the back of the throat.
Decongestants, like pseudoephedrine and phenylephrine, can be used to clear a runny nose and postnasal drip. These should not be used if you have high blood pressure or for a child under 6 years old unless prescribed by doctor. |
