Lecture 2.2 10/14/24 Flashcards
What are the options for delivering oxygen to a patient?
-flow-by
-mask
-oxygen chamber
-nasal cannula
-endotracheal tube
What are the characteristics of the receptors involved in coughing?
-stretch and C fibers
-mechanoreceptors and chemoreceptors
-numerous in larynx and airways
-respond to bronchoconstriction and bronchospasm
What is the cough reflex arc?
-stimulus in airway sends signal to brain via vagal airway sensory nerve
-brain sends signal via respiratory motor nerve to the respiratory muscles to initiate coughing
What are the characteristics of narcotics for antitussive therapy?
-central binding
-bind opioid receptors in cough center and depress sensitivity to afferent stimuli
-controlled substances; makes at home therapy more difficult
What are the characteristics of hydrocodone?
-contains homatropine, which exerts significant effects such as vomiting
-homatropine is meant to prevent abuse but also limits dosing
What are the characteristics of dextromethorphan?
-not a true opiate since it does not bind to mu or kappa receptors
-ineffective in dogs as an antitussive
What are the characteristics of maropitant/cerenia?
-NK1 receptor antagonist
-may be an antitussive useful for chronic cough
What are the bronchodilator classes and the species they are used in?
-anticholinergics: horses
-beta-receptor agonists: small animal and horses
-methylxanthines: small animal
Why is atropine not used as an antitussive?
too many side effects
What are the characteristics of ipratropium bromide/atrovet?
-aerosol quaternary amine
-topical form of atropine
Why should an antitussive therapy NOT activate alpha receptors in the sympathetic response?
-increases cGMP
-increases mucus production
-increases bronchiolar constriction
Why should an antitussive therapy activate beta receptors in the sympathetic response?
-increases cAMP
-causes bronchodilation
-decreases mucus production
What is the mechanism of action for adrenergic agents?
-stimulate beta receptors to ultimately increase cAMP and cause bronchodilation
-stabilize mast cells to decrease inflammatory response
-beta2 receptors are selective for bronchodilation, so direct cardiac effects are unlikely
What are the characteristics of terbutaline sulfate?
-selective beta2 adrenergic agonist
-used in dogs, cats, and horses
-administered SQ, IM, IV, PO, or elixir
What are the characteristics of clenbuterol sulfate?
-selective beta2 adrenergic agonist
-used in horses
-administered PO
What are the characteristics of albuterol sulfate?
-selective beta2 adrenergic agonist
-used in horses
-emergency drug in dogs and cats
-administered parenteral, oral, or inhalation
What are the methylxanthine drugs?
-caffeine
-theobromine
-aminophylline/theophylline
What is the mechanism of action for methylxanthines?
-inhibit PDE related breakdown of cAMP
-increased cAMP leads to greater relaxation
-antagonizes adenosine receptors that stimulate contraction
-less potent than beta2 agonists
-cause bronchodilation with risk of CNS and cardiac stimulation
How does aminophylline differ from theophylline?
-aminophylline contains ethylenediamine and water molecules
-aminophylline can be injected while theophylline can only be administered orally
Why is it important that aminophylline and theophylline have a low therapeutic index?
-there are lots of side effects
-dose adjustment is needed during drug monitoring
What are the glucocorticoids used in antitussive therapy?
-prednisone
-prednisolone
-dexamethasone
Why is the NSAID flunixin not commonly used in small animal antitussive therapy?
damaging to the kidneys
What is the mechanism of action of glucocorticoids?
-interacts with DNA
-suppresses multiple inflammatory genes that are typically activated in asthmatic airway
-stimulates production of lipocortin, which decreases prostaglandin production by suppressing phospholipase A
What are the outcomes of glucocorticoid therapy?
-decreased airway inflammation
-increased sensitivity and receptor density of beta2 receptors
-potential side effects including PU/PD and appetite changes
How are glucocorticoids administered?
-oral
-inhaled nebulization/aerosol
What are the characteristics of fluticasone?
-glucocorticoid
-local action
-less side effects
-used for asthma maintenance
What are the characteristics of NSAID use for antitussive therapy?
-inhibits cyclooxygenase to decrease prostaglandin production
-used in large animal for some lung diseases
-rarely used in small animal
