9. respriatrory system drugs

Chapter 9

Respiratory System Drugs

Copyright © 2011 Delmar, Cengage Learning

Basic Anatomy and Physiology

• The respiratory system is the body system that brings oxygen from the air into the body for delivery via the blood to cells

• Respiration is the exchange of gases between the atmosphere and the cells of the body

• Ventilation is the bringing in of fresh air


Basic Anatomy and Physiology


Respiratory Conditions

• Respiratory conditions are categorized into upper and lower respiratory conditions– Upper respiratory conditions in animals are mainly

caused by infectious agents that produce clinical signs such as congestion and coughs

– Lower respiratory conditions in animals include asthma, bronchitis, pneumonia, and chronic obstructive pulmonary disease (COPD)

• COPD in horses is commonly called “heaves”


Respiratory Drugs

• Expectorants– Increase the flow of respiratory secretions to

allow material to be coughed up from the lungs

– Increase the fluidity of mucus– An example is guaifenesin


Respiratory Drugs

• Mucolytics– Decrease the viscosity or thickness of

respiratory secretions– An example is acetylcysteine

(also used to treat acetaminophen toxicity)


Respiratory Drugs

• Antitussives– Suppress coughs– May be centrally acting or locally acting– Centrally acting antitussives include

butorphanol, hydrocodone, codeine, dextromethorphan, and trimeprazine (in a combination product)


Respiratory Drugs

• Decongestants– Decrease the congestion of nasal passages

by reducing swelling– Examples include phenylephrine and

pseudoephedrine


Respiratory Drugs

• Bronchodilators– Widen the lumen of the bronchi and counteract

bronchoconstriction– Examples include cholinergic blocking agents

(anticholinergics such as aminopentamide, atropine, and glycopyrrolate), beta-2-adrenergic agonists (such as epinephrine, isoproterenol, terbutaline, and albuterol), and methylxanthines (such as aminophylline and theophylline)


Respiratory Drugs

• Antihistamines– Block the effects of histamine– Antihistamine drug names usually end with –

amine– Side effects include CNS depression and

anticholinergic effects such as dry mouth– Examples include diphenhydramine and

chlorpheniramine


Respiratory Drugs

• Respiratory stimulants– Stimulate the animal to increase its

respirations– Examples include naloxone (usually used to

stimulate respiration following narcotic overdose) and yohimbine (used to reverse xylazine administration or overdose)


Asthma Drugs

• Glucocorticoids:– anti-inflammatory drugs administered orally or by inhalation– Orally used to treat feline asthma– Inhaled used to decrease swollen and narrowed airways by

decreasing inflammation– There are fewer side effects with inhaled glucocorticoids than

with oral ones

• Bronchodilators:– Used in addition to glucocorticoids in the treatment of feline

asthma– Side effects include tracheal or bronchial irritation


Asthma Drugs

• Methylxanthines:– Another group of bronchodilators used in the

treatment of feline asthma– Have a narrow therapeutic index

• Cyclosporin: – A fungal derived protein useful in the allergic

response in feline asthma– Side effects include nephrotoxicity and vomiting


Chronic Obstructive Pulmonary Disease (COPD) Drugs

• Is treated by using some forms of medication and keeping good management practices:– Keeping horses outside as much as possible– Reducing dust– Storing hay in a dry place– Improving ventilation in horse stables


Chronic Obstructive Pulmonary Disease (COPD) Drugs

• Glucocorticoids help decrease smooth muscle contraction, suppress inflammation, and reduce mucus production

• Inhaled glucocorticoids are used to decrease swollen and narrow airways

• Bronchodilators relax the smooth muscles of the airways– Can also be combined with other anti-inflammatory

drugs


9. respriatrory system drugs

Health & Medicine

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