Are blood insoluble or blood soluble drugs more quickly distributed in tissues?
Blood insoluble drugs have a more rapid increase in partial pressure. Partially blood-soluble drugs have a slower increase in partial pressure.
What is the affect of blood solubility on induction and recovery?
The more soluble the drug is in the blood, the longer induction/recovery will take
Rate the following drugs in order of blood solubility and induction/recovery time: methoxyflurane, isoflurane, and nitrous oxide.
methoxyflurane (long recovery time, high solubility), isoflurane (medium recovery time, medium solubility), and nitrous oxide (short recovery time, low blood solubility)
What is the fraction of delivered drug PP?
the alveolar concentration
What is the role of lipid solubility in anesthetic pharmacologic potency?
Lipid solubility determines how well a drug can get across cell membranes, including the blood-brain barrier. The more lipid soluble, the more potent the anesthetic is.
Rank the lipid solubility and MAC value (minimum alveolar concentration, pharmacologic potency) of the following drugs: methoxyflurane, isoflurane, and nitrous oxide.
Methoxyflurane (high lipid solubility, low MAC, more potent), isoflurane (medium lipid solubility, medium MAC, medium potency), nitrous oxide (low lipid solubility, high MAC, low potency)
What is the Minimum Alveolar Concentration?
The anesthetic dose that produces anesthesia (immobility to a noxious stimulus) in 50% of a patient populations.
What is the effect of acetylcholine on the bronchi?
Acetylcholine acts on the muscarinic acetylcholine receptors, increasing Ca++ concentrations, resulting in bronchoconstriction.
What is the effect of norepinephrine on the bronchi?
Norepi acts on alpha adrenergic receptors to decrease cAMP resulting in bronchoconstriction
What is the effect of epinephrine on the bronchi?
Epinephrine acts on beta2-AR to increase cAMP, resulting in bronchodilation
What are the treatments for bronchoconstrictive airway disease?
Address causes (antibiotics), anti-inflammatory drug therapy, and symptomatic treatment (bronchodilators)
What is the effect of acetylcholine on the mucus of the airway?
thick mucus
What is the effect of epinephrine on the mucus of the airway?
Decreased mediators, watery mucus
Albuterol
Beta2-AR agonist, increased cAMP which leads to bronchodilation, Aerosolized use in dogs and cats, most effective bronchodilator class, increase diameter of small/large airways, increase mucociliary clearance, decrease release of inflammatory mediators
Clenbuterol
Beta2-AR agonist, which increases cAMP and leads to bronchodilation, use in horses in Canada and Europe, in small animal has low bioavailability in first-pass metabolism, side effects of cardiac arrythmias, mydriasis, excitement, etc.
Theophylline
a type of methyxanthine (bronchodilator) that inhibits phosphodiesterase activity and decreases cAMP breakdown, also a competitive agonist at adenosine receptors (bronchoconstrictive effects). Results in dilation of large and small airways and mucociliary clearance and anti-inflammatory effects. Has high oral bioavailability, lots goes through hepatic phase 1 metabolism, low therapeutic index, serious side effects.
What are examples of bronchodilators that target muscarinic receptors? (3)
Atropine, glycopyrrolate, ipratropium
What can bronchodilators that target muscarinic receptors be used for?
severe asthmatic states unresponsive to other durgs, acute dyspnea, and bronchoconstriction produced by anti-choliesterase agents
What are the differences between atropine and glycopyrrolate and ipatropium?
Glycopyrrolate and ipatrpium do not cross the BB barrier, ipatropium is more effective than atropine as a bronchodilator, glycopyrrolate has a longer duration of action than atropine but also slower onset
What are the side effects of muscarinic receptor blockers?
tachycardia and decreased intestinal motility
What are the goals of antitussive therapy?
Decrease the frequency and severity of coughing without compromising effective evacuation of bronchopulmonary secretions. Usually given for non-productive coughs
What are the treatment strategies for cough in animals?
No treatment, remove causative stimulus, symptomatic treatment of non-productive cough
What drugs can be given to the site of irritation (airways)?
Mucosal anesthetics, demulcents, mucokinetic agents, bronchodilators
What drugs can be given to target the cough center (medulla)?
Opiates
What are examples of opiate antitussive drugs?
Codine, butorphanol, dextromethorphan
What is the mechanism of action of opiate antitussive drugs?
Decrease the sensitivity of the cough center to afferent stimuli, therefore decreasing the awareness of airway irritation
What is the action of codine?
It depresses the respiration by blunting CO2 sensitivity of brain respiratory centers, has human abuse potential
What types of drugs are butorphanol and dextromethorphan?
Opiate antitussive drugs
Dextromethorphan
Isomer of a codine derivative, no action at opiod receptors, unsure of antitussive mechanism, effective if used in combination with a bronchodilator. No abuse potential
Butorphanol
Agonist at opiod receptors (naloxone reverses), antitussive agent for use in non-productive coughs in dogs and horses. Some abuse liability
