Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
97 Cards in this Set
- Front
- Back
|
What are the classifications of drugs acting in the ANS?
|
drugs acting on the parasympathetic
drugs acting on sympathetic all by stimulation or inhibition |
|
|
What are the two catagories under parasympathomimetics?
|
direct-acting
indirect acting (only by one mechanism by inhibiting choline esterases) |
|
|
What are drug examples of parasympathomimetics?
|
Choline esters like Carbachol and Bethanechol
Cholinominetic alkaloids Muscarine and pilocarpine |
|
|
What are the effects of Ach?
|
vasoconstriction of bronchi
vasodilation decrease cardiac output (M2) increased GI motility constriction of pupil increase micturition contractility of skeletal muscle |
|
|
What is carbachol?
|
Direct acting
Classification: synthetic ester Mechanism: Muscarinic and nicotinic agonist Clinical uses: open angle glaucoma Problems: systemic vasodilation Pharmacokinetics - give IV, not very lipid soluble |
|
|
What is Bethanechol?
|
Direct acting
Classification: Synthetic parasympathomometic Mechanism: Muscarinic agonist Clinical uses: Postoperative nonobstructive urinary retention Problems: severe systemic cardiac affects Pharmacokinetics: give orally or SC not IM or IV Acetylcholinesterase does not inactivate bethanechol A quaternary ammonium compound Ionize non lipid soluble |
|
|
What is Pilocarpine?
|
Direct acting
Classification:Tertiary alkaloid Mechanism: muscarinic agonist Clinical uses: Open-angle glaucoma and to increase tear secretion. Which counter acts the mydriatic effect of sympathomimetic drugs Problems: systemic effects Pharmacokinetics: use locally Used with atropine to break the adhesion between the iris and the lens |
|
|
What drugs are indirect acting reversible parasympathomimetics?
|
Physostigmine
Neostigmine Edrophonium Pyridostigmine Demecarium |
|
|
What is Physostigmine?
|
indirect acting reversible parasympathomimetic
Classification: a tertiary amine Mechanism: counter acts central and peripheral effects of anticholinergic drugs like atropine Clinical uses: used as an opthamnic agent for open angle glaucoma Problems: use caustion with patients with seizure disorders Pharmacokinetics: administered parenterally IV or IM and topically on the eye crosses the BBB |
|
|
What is Neostigmine?
|
Classification: A quaternary amine
Mechanism: to antagonize the effects of nondepolarizing muscle Clinical uses: used to treat and diagnose myasthenia gravis, can stimulate GI motility and treat postoperative nononstructive urinary retention Problems: Pharmacokinetics: given orally and parenterally (IV or IM) Has a longer duration than edrophonium |
|
|
What is Edrophonium?
|
Classification: a quaternary amine
Mechanism: Indirect acting parasympathomimetic Clinical uses: used for diagnosing myasthenia gravis Problems: less adverse side effects because of short duration of action Pharmacokinetics: admimistered IM or IV |
|
|
What is Pyridomstigmine?
|
Classification: a quaternary amine
Mechanism: Indirect acting parasympathomimetic Clinical uses: used for treating myasthenia gravis Problems: Pharmacokinetics: admimistered IM or IV Atropine is used to treat toxicity of cholinesterase |
|
|
What is Demecarium?
|
Classification: a carbamate reversible cholinesterase inhibitor
Mechanism: Indirect acting parasympathomimetic Clinical uses: used for open angle glaucoma, topical ophthalmic miotic agent Problems: long duration of action organophosphates (12-48hrs) Pharmacokinetics: used topically |
|
|
What are drugs that are opthamic organophosphates?
|
Echthiophate
Isoflurophate Uses:They causes miosis and contraction of the ciliary muscle Decrease interocular pressure Clinical: Used in open angle glaucoma Problems: Has more topical adverse effects than any other antiglacoma drugs Large doses may cause systemic toxicity |
|
|
What are the characterizes of organophosphate poisoning?
|
Mechanism: muscarinic effects, nicotinic and CNS stimulations
Nicotinic blockade and CNS depression Clinical signs: nausea, vomiting, diarrhea, coilic, salivation, miosis, urintation, muscle fasciculation, temors, repiratory failure Treat with atropine 2-PAM (cholinesterase reactivator) |
|
|
What is Atropine?
|
Classification:parasymathetolytic, antichoninergics, cholinoceptor-blocking drug) atropine is a tertiary antimuscarinic
Mechanism: competitive antagonist to Ach on muscarinic receptors Clinical uses: Eye: mydriasis increase IOP decreased lacrimation Resp: bronchodilation and reducing secretion from the nose, decreases mucociliary clearance Cardio: tachcardia vasconstriction Urinary bladder: relaxation of wall of the gall bladder and contraction of the sphincter GI: decrease GI motility CNS: weak stimulation, blurred vision, mydriasis and cycloplegia (eye muscle paralysis) Problems: causes tachycardia Pharmacokinetics: admimistered PO, IV, IM and SC, readily absorbed wide distribution Metabolized in the liver and excreted in urine and milk USE IN INCOMPLETE AV BLOCK |
|
|
What is Scopolamine?
|
A tertiary antimuscarinic that produces CNS depression
Used in motion sickness Used as an ophthalmic agents to induce cycloplegia and for iritus and uveitis |
|
|
What is Dicyclomine?
|
A tertiary antimuscarinic that has less systemic side effects tha atropine and is an antispasmodic
|
|
|
What is Aminopentamide?
|
A tertiary antimuscarinic that is approved as an antispasmodic and to treat GT spasm in dogs and cats
Available PO,IM and SC |
|
|
What is Oxybutynin?
|
A tertiary antimuscarinic that is approved as adjunctive therapy for detrusor hyperreflexia in dogs and cats
|
|
|
What is Glycopyrroate?
|
A tertiary antimuscarinic that is more potent than atropine and antispasmodic, inhibits secretions
Less potent than atropine on cardio Used as preanesthetic, bronchodilator and GI antispasmodic Longer duration than atropine |
|
|
What is propantheline?
|
A tertiary antimuscarinic that also blocks nicotinic receptors
Used as a GU antispasmodic agent and for urinary incintinence (neurogenic bladder) Should not be used in patients with myasthenia gravis |
|
|
What is Ipratropium?
|
A tertiary antimuscarinic that is more potent than atropine as a bronchodilator and less potent than a beta 2 agonist
Does not alter mucociliary clearance Causes much less decrease in salivary secretion than atropine Can be used with albuterol as a bronchodilatory and used intranasally for rhinitis |
|
|
What are examples of catecholamine sympathomimetics?
|
Epinephrine
Norepinephrine Isoproterenol Dopamine Dobutamine |
|
|
What is Epinephine?
|
Classification: catecholamine sympathomimetics
Mechanism: a potent agonist of alpha 1 and 2 and beta 1 and 2 receptors Stimulation of Beta receptors increases cAMP while stimulation of alpha decreases cAMP Clinical uses: used for acute anaphylatic shock, bronchospasm, cardiac arrest, vasoconstrictor in surgical bleeding and combined with local anesthetics Problems: can't used in closed angle glaucoma, hypertension, DM, phenothiazine overdose Can causes sinus tachycardia, angina, hpertension, metabolic acidosis CNS stimulation Pharmacokinetics: administered topically, inhalation, IM, SC, IV USE IN COMPLETE AV BLOCK |
|
|
What are the pharmacological effects of epinephrine on the eye?
|
Mydriasis alpha 1
Cycloplegia beta 2 Lowers interocular pressure in patients with open angle glaucoma |
|
|
What are the pharmacological effects of epinephrine on the respiratory tract?
|
Bronchodilation and stabilization of mast cells (beta 2)
Increased mucociliary clearance Decrease in bronchial secretion and decongestant effect |
|
|
What are the pharmacological effects of epinephrine on the cardiovascular system?
|
Increase cardiac automaticity
Increased systolic pressure Arteriolar vasconstriction a1 and a2 in blood vessels in the skin, subcutaneous and viscera and arteriolar vasodilation (b2) in blood vessles in skeletal muscles and coronaries Low doses diastolic pressure decreases while at higher doses diastolic pressure increases |
|
|
What are the pharmological effects of epinephrine on metabolism?
|
Hyperglycemia due to increased glycogenolysis (b2)
Hyperglycemia die to gluconeogenesis and inhibition of insulin release (a2) Lipolysis of TG increase free fatty acids |
|
|
What is norepinephrine?
|
catecholamine sympathomimetic that acts as an alpha and beta 1 adrenergic agonist
Increase both systolic and diastolic pressure Causes less increase in myocardial O2 consumption than epinephrine Increase peripheral resistance can cause reflex bradycardia Used in intravenous infusion for septic and cardiogenic shock and hypotension |
|
|
What is isoproterenol?
|
A synthetic sympathomimetic amine
A potent beta 1 and 2 agonist Used by inhalation for brochial asthma and parenterally as a cardiac stimulant and bronchodilator |
|
|
What is Dopamine?
|
Acts as an agonist of dopaminergic receptors and beta 1 and alpha adrenergic receptors and indirectly stimulating the release of norephinephrine
Dopaminergic receptors are the most senestive, than B1 and last are alpha receptors Causes vasodilation and increase GFR is the most useful effect in conditions with decrease renal perfusion Used by IV for: Cardiogenic and septic shock Congestive heart failure Oliguric renal failure To correct hypotenstion due to inhalation anesthetics |
|
|
What is Epherdrine?
|
Alkaloid from Ephedra plant
A noncatecholamine that directly acts as adrenergic agonist on alpha and beta receptors and indirectly by releasing norepinephrine Generally, it has similar pharmacological effects as epinephine and also stimulates the CNS Has a slower onset and longer duration of action than epinephrine Used topically Continuous use causes tachyphylaxis |
|
|
What is Amphetamine?
|
Indirect acting sympathomimetic
Acts by stimulating release of norepinephrine |
|
|
What is Cocaine?
|
Indirect acting sympathomimetic
Acts by interfering with the reuptake or norepinephrine has CNS stimulation local anesthetic by blocking NA channels CNS stimulation by inhibiting norepi |
|
|
What are monamine oxidase inhibitors?
|
Used as anti depresssants that interfere
MAOI |
|
|
What are alpha 1 selective agonists?
|
Phenylephrine
Methoxamine Direct active non catecholamines |
|
|
What is Phenylephrine?
|
Alpha one agonist
Used as decongestant for nasal and eye congestion Used parenterally to increase BP and treat paroxysmal superventricular tachycardia |
|
|
What are beta 2 selective agonists?
|
More selective in stimulating b2 than b1
B2 causes bronchodilation and stabilization of mast cells and increase mucociliary clearance Increase cardiac stimulation, vasolation, uterine relaxation and hyperglycemia Causes moderate hypokalemia by stimulating Na/k Salmeterol Albuterol Terbutaline Metaproterenol Clenbuterol Isoxuprine- not used as broncho dilation know this order of drugs |
|
|
What are sympatholytic (adrenoceptor antagonists)?
|
Direct acting (can be selective and non selective)
Alpha blockers Beta blockers Beta and alpha one blockers |
|
|
What are alpha blockers?
|
Sympatholytic, can be nonselective and selective
Nonselective = phentoamine and phenoxybenzamine Used for detrusor areflexia in dogs and cats Hypertension due to pheochromocytoma in dogs Prazosin = alpha 1 selective blockers |
|
|
What are Beta blockers?
|
Sympatholytic
Nonselective = propranolol, timolol, sotalol Beta 1 selective blockers Atenolol |
|
|
What are beta and alpha one blockers?
|
Sympatholytic
Carvedilol (drug example) Antioxidant Inhibits endothelin (ET) release |
|
|
What is the mechanism of action and pharmacological effects of nonselective beta blockers?
|
Act as competetive beta 1 and 2 antagoinsts
Decreases heart rate and cardiac output and decreases in systolic pressure and myocardial O2 demand Eye lower IOP by reducing the volume Respiratory bronchoconstriction in bronchial asthma Metabolic - hypoglycemia by inhibiting glycogenolysis (b2) Urinary system decreased renal blood flow and GFR |
|
|
What are the pharmacokinetics of nonselective beta blockers?
|
Administered as opthalmic agents, orally and parenterally
High lipid soluble Readlily absorbed orally and cross the BBB Duration of action is several hours Metabolized in the liver and excreted in the urine |
|
|
What are the therapeutic uses of nonselective beta blockers?
|
Glaucoma
Supraventricular and ventricular tacharrythmias Myocardial hypertrophy Hyperthyroidism Hypertension Congestive heart failure due to dilated cardiomyopathy |
|
|
What are the adverse effects of non selective beta blockers?
|
Sudden withdrawal causes tachycardia (up regulation of b1)
Sinus bradycardia (AV block and can be treated with atropine, epinephrine, isoproterenol or glucagon) Hypotention Bronchospasm Hypoglycemia Hyperkalemia Hypertriglyceridemia sedation |
|
|
What are beta 1 selective blockers used for?
|
Preferred in patients with bronchial asthma
Peripheral vascular occlusive disease Diabetes mellitus Effective in decreasing peripheral resistance than nonselecive beta blockers |
|
|
What are muscle relaxants?
|
drugs that cause muscle relaxation centrally or peripherally and have an unknown mechanism of actions
drugs such as: Guafenesin Methocarbamol |
|
|
What are the clinical uses for muscle relaxants (Guanfensin)
|
approved in horses but also used in cattle
as part of an anesthetic protocol what facilitates intubation, smooth induction and recovery and anesthetic sparing affect possible expectorant in horses |
|
|
What are the drug interactions with muscle relaxants (guafenesin)?
|
triple dipe
guafenesin + xylazine or detomindine + ketamine thiopental Physotigmine |
|
|
What are precautions to take when using muscle relaxants (guafensin)?
|
Thombophlebitis with 10% soln
hemolysis with less than 10% in cattle give at 5% precipitates out of solution at 22C or cooler extralabel use in food animals (3days in meat, 48 hours in milk) |
|
|
What is Methocarbamol?
|
muscle relaxant approved for dogs, cats and horses
Given IV and PO in dogs and cats and IV in horses Carbamate of guafenesin not metabolized to guafenesin Unknown mechanism of action |
|
|
What are the clinical uses of Methocarbamol?
|
adjunct for treating acute inflammatory and traumatic conditions of the skeletal muscle
to reduce muscular spasms In intervertebral disk disease Urethral onstruction Urinary retention Strychnine, metadehyde, tetanus, permethrin toxicosis |
|
|
What are the precautions/contradictions of Methocarbamol?
|
Sedation
Salivation Emesis Dark urine |
|
|
What are examples of peripheral sites of action?
|
Motor neuron
NMJ Muscle cell |
|
|
What is Dantrolene?
|
A muscle relaxant
Ryanodine receptor antagonist Inhibits Ca2 release from the sarcoplasmic reticulum Used in the treatment of malignant hyperthermia, functional urethral obstruction, post anesthetic mitosytis, exertional rhabdomyolysis |
|
|
What are neuromuscular blockers?
|
Drugs that causes paralysis in skeletal muscle. Must be used only when animals are unconscious before used, they must be ventilated.
NMB are used to perform tracheal intubation and institute artificial respiration. Drug not to be used for beginners |
|
|
What are the different types of neuromuscular blockers?
|
Depolarizing (noncompetitive) blockers
Nondepolarizing (competitive) blockers |
|
|
What is Succinylcholine?
|
A depolarizing blocker
|
|
|
What is a phase I block?
|
Activation of nicotinic Ach receptors induces prolonged depolarization of the motor end plate
No complete repolarization prevents stimulation by Ach (depolarizing block) |
|
|
What is phase II block
|
Nicotinic Ach receptors in inactivated state are unable to respond to Ach
|
|
|
What are the pharmacokinetics of depolarizing blockers?
|
Given IV and rarely IM
Hydrolization by plasma pseudocholinersterases Succinylcholine-succinlmonocholine-succinic and choline Acts in one circulation time duration of action 2-3min (20 min in dogs and ruminants) Causes transient asynchronous muscle twitching followed by flaccid paralysis Causes nicotinic Ach receptors at autonomic ganglia are less sensitive than those at the NMJ Ganglionic stimulation - hypertension Cardiovascular Transient bradycardia Hypertension (in unanesthetized animals) Increased arrhythmogenicity to epinephine in halothane-anesthetized patients Increased susceptibility of the heart to the action of digitalis preparations Ocular - increased intraocural pressure due to contraction of ocular muscles Serum potassium -hyperkalemia due to K release from skeletal muscles |
|
|
,What are the uses of depolarizing blockers?
|
Facilitation of endotracheal intubation
Crash induction technique in dogs and cats Prevenents laryngeal spam is cagt To intubate pig and rabbits Muscle relatation during surgery (rarely) C-section in dogs Adjunct to general anesthetics No longer used (thiopental and succinylcholine in horses) |
|
|
What are the adverse effects of depolarizing neuromuscular blockers?
|
Apnea - artificial respiration
Muscle fiber damage - increased creatine kinase, postop muscle pain Hyperkalemia Bradycardia Increased arrhymogenicity to catecholamines Malignant hyperthermia in susceptible animal |
|
|
How do you reverse neuromuscular blockers?
|
Reversal is usually not needed, especially in dogs but you can provide artificial respiration
|
|
|
What are the precautions and contraindications of neuromuscular blockers?
|
Keep refrigerated to avoid spontaneous hydrolysis
Cholineresterase inhibitors Glaucoma Cardiac disease |
|
|
What are the drug interactions for neuromuscular blockers?
|
Aminoglycosides
Magnesium salts Local anesthetics Cholinesterase inhibitors Centrally-acting muscle relaxants Digitalis preparations |
|
|
What are some examples of Competitive neuromuscular blockers?
|
Pancurorium
Atracurium Vecuronium Mivacurium Rocuronium |
|
|
What is the mechanism of action of competitive neuromuscular blockers?
|
Competitive antagonism with Ach for nicotinic receptors at the motor end plate
|
|
|
What are the pharmacokinetic of competitive neuromuscular blockers?
|
Given IV (rarely IM)
Poor penetrators of membranes Inactivated by plasma esterases Metabolized in the liver Excreted in bile Excreted by the kidneys |
|
|
What are the pharmacological effects of competitive neuromuscular blockers?
|
Skeletal muscle - flaccid paralysis
Autonomic- nicotinic Ach receptors at autonomic ganglia and less sensitive that those at the NMJ Ganglionic blockade = hypotension Cardiovascular- transient tachycardia (in anesthetized animals) Weak hypotension Histamine release - only with tubocurarine (increases increased respiratory tract secretions, bronchospasm hypotension) |
|
|
What are the clinical uses of competitive neuromuscular blockers?
|
Facilitation of endotracheal intubation
Thoracic/upper abdominal surgery Facilitate orthopedic manipulation |
|
|
What are the adverse effects of competitive neuromuscular blockers?
|
Apnea
Histamine release hypotension |
|
|
How do you reverse competitive neuromuscular blockers?
|
Artificial respiration
Cholinesterase inhibitors (atropine or glycopyrrolate) |
|
|
What are the precautions of competitive neuromuscular blockers?
|
Brochospasm
Hypotension Liver or kidney disease |
|
|
What are the drug interactions of competitive neuromuscular blockers?
|
Inhalation anesthetics
Aminoglycosides Magnesium salts Local anesthetics Centrally acting muscle relaxants Cholinesterase inhibitors |
|
|
What is pulmonary edema
|
Fluid in the lungs and causes hypoxia, cyanosis, unconsciousness and death
|
|
|
What do you do to treat pulmonary edema?
|
Furosemide
Oxygen (give air breaks) Inotropic agents - L ventricular failure Colloids - correct hypoalbuminemia Morphine - decrease RR and anxiety Bronchodilators Antibiotics corticosteroids |
|
|
What are the problems seen with upper respiratory tract infections?
|
Inflammed mucus membranes
Excessive mucus production Thick mucus coughing |
|
|
What do you see with Bronchitis?
|
Inflammed mucus membranes
Excessive mucus production Thick mucus coughing Cilia not working Airway hyperreactivity |
|
|
What do you see in patients with pneumonia?
|
hypoxia
|
|
|
How do you treat respiratory problems?
|
Treat primary problem
Many respiratory infections caused by viruses Symptomatic treatment of secondary problem |
|
|
What are expectorants?
|
Mucokinetics that:
Increase amounts of mucus Decrease viscosity of mucus Increase ciliary action Cough up mucus |
|
|
What are examples of mucolytic expectorants?
|
Not used much in vet med
Acetylcysteine Carbocysteine Bromhexine |
|
|
What are cilia augmentors?
|
Increase beat frequency of airway cilia - functional mucociliary escalator system
Expectorants Expectorants = KI AlCl B2 agonists = Turbutaline, clenbuterol, albuterol Methylxanthines = theophylline, aminophylline |
|
|
What are antitussives?
|
drugs that reduce coughing
use in unproductive coughing local anesthetic = lidocaine, benzonatate opiods = butorphanol, hydrocodone, tramadol bronchodilators |
|
|
What are bronchodilators?
|
Reverse bronchoconstriction in cats and horses (used most often)
Used to help in asthma |
|
|
What are examples of bronchodilators?
|
Sympathomimetics
A1 agonists - pseudoephedrine B2 agonist tubutaline, clenbuterol, albuterol Methylxantines = theophylline, animophylline Anticolinergics = atropine, glycopyrrolate, ipratropium Glucocorticoids= betamethasome, dexmethasone |
|
|
What are methylxanthines?
|
a type of bronchodilator medication that act by nonselective inhibition of adenosine receptors
A1 decreases HR A2a coronary artery vasocilation A2b bronchonstriction A3 inhibition of neutrophil degranulation |
|
|
What are the pharmocological effects of Methylxanthines?
|
mild positive ionotropic
vasodilations see tachycardia mild diruetic activity CNS stimulation |
|
|
What are the pharmacokinetics of methylxanthines?
|
given orally
metabolized in the liver metabolites excreted in the urine |
|
|
What is Theophylline?
|
a methylxanthine
a bronchodilator used in dogs and cats not useful in horese (toxic) or cattle (no effect) |
|
|
What is pentoxifylline?
|
a methylxanthine but has no effect on respiratory pharmacology
used in horses for laminitis and navicular disease |
|
|
What are the side effects of Methyxanthines?
|
vomiting
tachycardia Diuresis CNS stimulation at high doses |
|
|
What do you see in Methylxanthine toxicity?
|
Acute onset short duration
Clinical signs the same as side effects Bloodwork is non specific Need to gastric lavage, induce vomiting or give activated charcoal Antoconvulsants, antiarrhythimics, fluids, oxygen Good prognosis if no major complications |
|
|
What is Doxapram?
|
A respiratory stimulant
stimulates the CNS Increases minute volume |
