Respiratory Drugs Flashcards
What are 7 categories of respiratory drugs?
- Bronchodilators and anti-inflammatory drugs
- Antitussives
- Mucokinetics
- Expectorants
- Decongestants
- Drugs for pulmonary edema
- Antifoaming agents
What are three categories of bronchodilators?
- Beta adrenergic agonists
- Methylxanthine derivatives
- Anticholinergics
What is the non-selective B-agonist that is the DOC for treating life-threatening bronchospasm?
Epinephrine!
What are some fun facts about Epinephrine?
- DOC for emergency treatment of life-threatening bronchospasm.
- Give IV or IM for a single treatment.
- Short acting (>1 hour)
- Not for long-term use
- Adverse effects are due to stimulation of alpha and beta adrenergic receptors.
What is another non-selective B-agonist (aside from Epinephrine) that is used as a bronchodilator?
Isoproterenol
How is Isoproterenol administered and what are its adverse effects?
Isoproterenol is administered by inhalation or injection. Adverse effects are due to stimulation of B1 and B2 receptors.
What are some fun facts about B2-Selective Agonists?
- More selective in stimulating B2 than B1.
- Stimulation of B2 causes bronchodilation and stabilization of mast cells and also increases mucociliary clearance.
- Continuous use can result in tolerance.
What are some effects that are caused by B2-selective agonists?
Can cause cardiac stimulation, vasodilation, uterine relaxation, hyperglycemia, and may cause moderate hypokalemia by stimulating Na/K ATPase.
What are the uses for B2-selective agonists?
Bronchodilators that are used to treat and prevent acute bronchoconstriction due to bronchial asthma in cats or COPD (chronic obstructive pulmonary disease) in horses.
What are the adverse effects of B2-selective agonists?
- Sinus tachycardia and premature ventricular contractions.
- CNS stimulation
- Tremors/muscle cramps
- Hyperglycemia
- Moderate hypokalemia
- Uterine relaxation
Clenbuterol, a B2-selective agonist, has what kind of effect?
It has anabolic effect and large doses cause muscle twitching and hyperthermia.
What are some fun facts about Terbutaline?
- Duration of action: 6-8 hrs
- Administered orally or by injection in small animals.
- Administered as an injection in horses; no oral absorption.
What are some fun facts about Metaproterenol?
- DOA: 4 hours
- Administered orally as tablets
What are some fun facts about Albuterol?
- Administered orally and by inhalation in cats and horses.
- Aerosol is approved for use in horses.
T/F: Clenbuterol is safe to use in food animals.
False! It is illegal to use Clenbuterol in food animals.
What two B2-selective agonists are not used in animals?
Salmeterol and Formoterol
What four drugs are classified as Methylxanthine Derivatives?
- Theophylline
- Aminophylline
- Caffeine
- Theobromine
What is the MOA for methylxanthine derivatives?
Antagonism of adenosine receptors, inhibition of phosphodiesterase, acting on intracellular calcium, inhibition of degranulation of mast cells and inhibition of prostaglandins.
How are methylxanthine derivatives administered, dosed and metabolized?
- They are administered orally and parenterally.
- Relatively large Vd in dogs, horses and cattle, but lower in cats.
- Metabolized by methylation in the liver.
How long do methylxanthine derivatives work?
Several hours
What are the pharmacological effects of methylxanthine derivatives?
- CNS stimulation
- Respiratory: bronchodilation, anti-inflammatory of microvascular leakage, stimulating mucociliary clearance and improved breathing.
- Cardiovascular: stimulation of myocardial contractility, increasing heart rate and systolic pressure, and vasodilation.
- Stimulation of skeletal muscles/
What are some therapeutic uses of methylxanthine derivatives?
Bronchoconstriction, bronchial asthma, COPD
Aminophylline is used in treatment of what?
Severe cases of congestive heart failure and anaphylaxis.
What are some adverse effects of methylxanthine derivatives?
- CNS stimulation
- Salivation, nausea, vomiting
- Diuresis
- Tachycardia, tachyarrhythmias, and hypotension.
What are three contraindications/precautions for methylxanthine derivatives?
- Cardiac disease
- Peptic ulcer disease
- Seizure disorder
What are two drug interactions of methylxanthine derivatives?
- Cardiac stimulants (tachycardia)
2. Inhalation anesthetics (hypotension)
What are three anticholinergic drugs?
- Ipratropium
- Atropine
- Glycopyrrolate
What do anticholinergics do to the PNS and SNS?
They block the PNS, so they will cause bronchodilation but also probably other SNS signs.
Name six categories of Anti-Inflammatory drugs.
- Cromolyn sodium
- Glucocorticoids
- Leukotriene Inhibitors
- NSAIDs
- B-adrenergic agonists
- Methylxanthines
What is the MOA of Cromolyn Sodium?
Inhibits release of histamine, leukotrienes, and other substances from sensitized mast cells. Does not cause bronchodilation.
What is cromolyn sodium used for?
- Occasionally used to stabilize mast cells in hypersensitive airways.
- Nebulized to horses prophylactically in treatment of COPD.
What drug is used as a leukotriene receptor antagonist?
Zafirlukast
What drug is used as a 5-Lioxgenase inhibitor?
Zileuton
What are leukotriene inhibitors used for?
Used orally for prophylaxis and chronic treatment of bronchial asthma.
Name two NSAID drugs.
- Flunixin
2. Aspirin
What is Flunixin used to treat?
Used in horses and dogs to treat pulmonary effects from endotoxin. Used in cattle to treat Bovine Respiratory Disease and inflammatory respiratory problems.
What is Aspirin used for?
Used as an anti platelet for treatment of pulmonary thromboembolism in small animals.
What is the MOA of antihistamines?
Competitive antagonists to H1-receptors.
What are antihistamines used for and when are they not clinically useful?
May be useful in animals with chronic respiratory disease due to effects of bronchia secretions. Generally not clinically useful in control of bronchial asthma.
What are antitussives?
Drugs that decrease the frequency and severity of non-productive coughs without impairing mucociliary defenses.
T/F: Antitussives are centrally acting.
True
How are opioids used as antitussives?
Opioids directly depress the cough center in the medulla by activating Mu or Kappa receptors.
What drug has no activity on opioid receptors and may act on NK receptors?
Dextromethorphan
What are five opioid antitussive drugs?
- Codeine
- Hydrocodone
- Tramadol
- Butorphanol
- Morphine
What are some fun facts about Codeine?
- Controlled drug
- Oral absorption is slow and inconsistent in dogs and has low systemic levels.
- Side effects are mainly sedation and constipation.
What is the DOC for symptomatic treatment of cough in dogs?
Hydrocodone
What are three fun facts about Hydrocodone?
- More potent than Codeine
- Hydrocodone + Homatropine is used in small animals.
- Some consider it the first drug of choice for symptomatic treatment of cough in dogs.
What are some fun facts about Tramadol?
- Inexpensive, orally administered, and not controlled.
- Effective in dogs.
- Has opioid, serotonin, and alpha-2 activity.
Which opioid antitussive is potent for use in dogs?
Butorphanol
Why is Butorphanol administered IV or SQ?
It has low oral bioavailability
What are some fun facts about Butorphanol?
- Opioid agonist-antagonist
- Potent antitussive in dogs
- Administered IV or SQ because it has low oral bioavailability.
- Duration of action is longer than Codeine (4-10 hours.)
What are some fun facts about Morphine?
- Controlled drug
- Antitussive effect
- Oral administration has poor bioavailability.
What makes Dextromethorphan a non-opioid antitussive?
It does not act on Mu or Kappa receptors.
What effects does Dextromethorphan have?
It causes mild analgesic effects by acting as a NMDA antagonist (glutamate receptor.)
What side effects does Dextromethorphan have in dogs?
Vomiting following oral administration and CNS effects following IV administration. Routine use is dogs is not recommended.
What are Mucokinetics?
Drugs that facilitate the removal of secretions from the respiratory tract.
Mucokinetic B-agonists and methylxanthines act by what?
Stimulating ciliary activity
T/F: Hydration with saline or sterile water, increasing pH with sodium bicarb or breaking disulfide bonds in the mucus all act by decreasing viscosity of bronchial secretions.
True
What are Expectorants?
Drugs which increase the volume and fluidity of respiratory secretions.
Potassium iodide and EDDI act reflexively by _____?
Irritations of gastric mucosa.
Expectorants ______ and _____ _____ cause direct stimulation.
Guaifenesin and volatile oils cause direct stimulation.
What are the four decongestant vasoconstrictors?
- Phenylephrine
- Ephedrine
- Pseudoephedrine
- Phenylpropanolamine
What are the seven decongestant H1-antagonists?
- Diphenhydramine
- Hydroxyzine
- Chlorpheniramine
- Promethazine
- Cyproheptadine
- Cromolyn sodium
- Glucocorticoids
What is Oxygen used for?
Treatment of hypoxemia or respiratory acidosis due to hypoventilation and accumulation on CO2.
How is Oxygen administered?
Via intubation, mask, nasal O2, etc.
What is an adverse effect of Oxygen and what is it contraindicated against?
High levels of oxygen (100%) for long periods of time can be toxic to the lungs (use
What is Doxapram used for and where does it act?
Doxapram is approved in dogs, cats, and horses as a respiratory analeptic. It is used for reversal of respiratory depression due to inhalation and barbiturate anesthesia and to stimulate respiration in the neonate when it is depressed. It acts directly on the respiratory center.
How is Doxapram administered?
IV, IM, SQ, sublingual or in umbilical veins.
Large doses of Doxapram cause what?
Seizures
What does Doxapram reverse?
Acepromazine, Xylazine or Droperidol-Fentanyl in dogs and Thiopental-Acepromazine in cats.
What are two classes of drugs that treat pulmonary edema?
- Diuretics
2. CHF drugs
What two drugs are used as antifoaming agents?
- Nebulization of ethyl alcohol
2. Silicone spray.
