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Unformatted text preview: Treatment of Cough and Cold Symptoms For symptomatic relief of cough and cold symptoms the following types of drugs are used: antitussives, antihistamines, decongestants and expectorants. List of Available Antitussives Used in Respiratory Conditions diphenhydramine (Benadryl) benzonatate (Tessalon Perles) guaifenesin (Robitussin) dextromethorphan (DM) (Delsym) codeine (Codeine) hydrocodone (many combinations) Pharmacodynamics of the Individual Antitussive Drugs DIPHENHYDRAMINE - As an antihistamine, diphenhydramine blocks H-1 receptors in the brain stem, the center of the cough reflex. By blocking these receptors, the normal nervous system reflex that detects intrabronchial irritants and actuates the cough reflex is blocked. In addition to blocking histamine receptors, all antihistamines also have antagonist activity on cholinergic receptors (i.e., have anticholinergic effects). BENZONATATE - Benzonatate is a local anesthetic. It blocks the propagation of nerve impulses from the sensory nerve endings in the bronchial mucosa. By blocking the impulses at their source, the cough reflex center in the brain stem does not receive the irritant signal and the cough reflex is blocked. GUAIFENESIN - Guaifenesin stimulates the respiratory mucosa to increase the output of watery secretions. The increased water then coats the mucosa and, by wetting the surface, the irritation of the mucosa is diminished. By decreasing the irritation in the lung, the cough reflex is reduced. DEXTROMETHORPHAN - Dextromethorphan is an opiate drug. As such, it blocks opiate receptors in the brain stem and blocks the cough reflex by blocking nerve transmission in the cough 1 Treatment of Cough and Cold Symptoms center. [Note: Dextromethorphan is unique among the opiate drugs in that it does not block opiate receptors in the remainder of the brain to any significant degree and does not have analgesic effects or the other adverse effects associated with the other opiates.] CODEINE AND HYDROCODONE - Codeine and hydrocodone are true opiate drugs. As such, they block opiate receptors in the brain stem and block the transmission of irritant nerve impulse sensations through the cough center. Being true opiates, however, they have the potential to have all of the pharmacologic and adverse effects of the typical opiate analgesic drugs. Pharmacokinetics of the Individual Antitussive Drugs All of the cough suppressants (when used as such) are administered orally. They undergo either full or partial metabolism by the liver and are excreted in the urine either as parent drug or as metabolite. Advantages of the Individual Antitussive Drugs DIPHENHYDRAMINE - Available as a capsule or as a syrup; this may be an advantage in patients who have sore throat and may not be able to swallow easily - Rapid onset of action (15 min.) - Good duration of action (4-6 hrs) - Inexpensive - Available over-the-counter - May be useful to treat other histamine problems that may be associated with the cough (i.e., allergic rhinitis) cough (i....
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This note was uploaded on 05/19/2011 for the course NURSING 517/617 taught by Professor Lipstate during the Spring '11 term at University of Louisiana at Lafayette.
- Spring '11