Midterm 1 Flashcards
(84 cards)
1
Q
Reserpine
A
- sympatholytic
- acts on adrenergic presynaptic neurotransmitters
- fxn: prevents the reuptake and vesicular storage of norepi within the presynaptic terminal so norepi is degraded by MOA
- can cause sedation
2
Q
Botulinum toxin
A
- acts on cholinergic presynaptic neurotransmitters
- fxn: inhibits the release of ACh into the synaptic cleft
3
Q
Organophosphates (ex/ insecticides)**
A
- parasympathomimetic
- acts on cholinergic neurotransmitters in the synaptic cleft
- fxn: cholinesterase inhibitor that blocks the breakdown of ACh to make acetate and choline. This results in more ACh in synapse so increases the activity of cholinergic receptors –> parasympathetic signs predominate
- IRREVERSIBLE! so will be more potent and longer acting (more dangerous though)
- fxn: used for dewormers or insecticides
4
Q
Neostigmine
A
- parasympathomimetic
- acts on the cholinergic neurotransmitters in the synaptic cleft
- fxn: cholinesterase inhibitor that blocks the breakdown of ACh to make acetate and choline. This results in more ACh in the synaptic cleft so increases the activity of cholinergic receptors. –> parasympathetic signs will predominate
- REVERSIBLE - less potent than irreversible drugs
- used to reverse parasympatholytic overdose (ex atropine)
- use: myasthenia gravis (condition with a decreased amount of nicotinic receptors on post synaptic terminal) so the ACh staying in the synapse longer helps the receptor get stimulated so more muscular activity
5
Q
Physostigmine
A
- parasympathomimetic
- acts on the cholinergic neurotransmitters in the synaptic cleft
- fxn: cholinesterase inhibitor that blocks the breakdown of ACh to make acetate and choline. This results in more ACh in the synaptic cleft so increases the activity of cholinergic receptors. –> parasympathetic signs will predominate
- REVERSIBLE - less potent than irreversible drugs
6
Q
Edrophonium
A
- parasympathomimetic
- acts on the cholinergic neurotransmitters in the synaptic cleft
- fxn: cholinesterase inhibitor that blocks the breakdown of ACh to make acetate and choline. This results in more ACh in the synaptic cleft so increases the activity of cholinergic receptors. –> parasympathetic signs will predominate
- REVERSIBLE - less potent than irreversible drugs
- used to reverse parasympatholytic overdose (ex/ atropine)
- use: myasthenia gravis (condition with a decreased amount of nicotinic receptors on post synaptic terminal) so the ACh staying in the synapse longer helps the receptor get stimulated so more muscular activity
7
Q
Selegiline
A
- acts on adrenergic neurotransmitters within the synaptic cleft
- fxn: MAO inhibitor that blocks the breakdown of NE into its metabolites
8
Q
Amatraz
A
- acts on adrenergic neurotransmitters within the synaptic cleft
- fxn: MAO inhibitor that blocks the breakdown of NE into its metabolites
9
Q
Fluoxetine (Prozac)
A
- acts on the CNS in regards to neurotransmitter reuptake
- fxn: selective serotonin reuptake inhibitor so there is more serotonin staying in the synapse
10
Q
Domipramine (clomicalm)
A
- acts on the CNS in regards to neurotransmitter reuptake
- fxn: inhibits the reuptake of NE and serotonin so there is more serotonin in the synapse to react with the receptors
- is an antidepressant
11
Q
Bethanechol
A
- parasympathomimetic drug - cholinergic agonist
- direct acting agonist that responds more to muscarinic receptors than nicotinic
- not commonly used. can be used to stimulate the detrusor muscle of the bladder to contract if the dog or cat has a flaccid bladder. Need to make sure the urethra is open before you try this.
- may also cause salivation and defecation
12
Q
Pilocarpine
A
- parasympathomimetic drug - cholinergic agonist
- direct acting agonist that responds more to muscarinic receptors than nicotinic
- used to ophthalmology to either constrict the pupil (topically applied) or decrease intraocular pressure (glaucoma)
13
Q
Atropine **
A
- parasympatholytic drug - cholinergic antagonist (competes with ACh for cholinergic receptors)
- acts more strongly to muscarinic receptors than nicotinic receptors
- decreases vagal tone, causing increased heart rate (used preanesthetic protocol for sm animal)
- decrease salivation and sweating
- need higher doses to decrease GI motility or secretion
- pupillary dilation
- increase diameter of airway -counteracting bronchoconstriction
- not used much with asthma because of its other side effects
- can be used to counteract organophosphate poisoning
- used IV,SC, IM
- fasting acting so it can be used in emergencies or for routine use
- crosses BBB and placenta
14
Q
Glycopyrrolate
A
- parasympatholytic drug - cholinergic antagonist
- acts more strongly to muscarinic receptors than nicotinic receptors
- not as fast acting as atropine but not as potent either so it is used in preanesthetic protocol with a decreased risk of tachycardia
- IV,IM
- doesnt cross BBB or placenta and its action is peripheral not central
15
Q
Scopolamine
A
- parasympatholytic drug - cholinergic antagonist
- acts more strongly to muscarinic receptors than nicotinic receptors
- anti-spasmotic so it reduces intestinal pain in horses not going to Sx for colic.
- also increases heart rate, making it problematic with colic because increased heart rate is determining factor for going to Sx or not.
16
Q
Epinephrine
A
- sympathomimetic drug - adrenergic agonist
- a1 = a2, b1 = b2
- heart: b1 increase heart rate and contractility, therefore increasing cardiac output -less efficient cardiac cells so not for long term treatment
- blood pressure: a1 causes peripheral vasoconstriction and b1 causes increased CO so overall increases bp; b2 in skeletal muscle causes vasodilation
- blood is shunted to areas needed for fight or flight
- lungs: bronchodilation (b2)
- eyes: dilation of pupil
- GI: decreased gastric motility and secretion
- metabolism: increase blood glucose and decrease insulin release
- not an oral dose because degraded in GI tract and it is used for emergencies!!!
17
Q
Norepinephrine
A
- sympathomimetic drug - adrenergic agonist
- a1 = a2, b1 > b2 (so no skeletal muscle vasodilation or bronchodilation)
- heart: b1 increase heart rate and contractility, therefore increasing cardiac output. baroreceptor reflex decreases heart rate after it increases
- blood pressure: a1 causes peripheral vasoconstriction and b1 causes increased CO so overall increases bp
- blood is shunted to areas needed for fight or flight
- eyes: dilation of pupil
- GI: decreased gastric motility and secretion
- metabolism: increase blood glucose and decrease insulin release
- NOT USED IN VET MED
18
Q
Isopreterenol
A
- sympathomimetic drug - adrenergic agonist
- b1 = b2»_space; a (no impact on systemic bp)
- can be used as a bronchodilator
19
Q
Dobutamine
A
- sympathomimetic drug - adrenergic agonist
- b1 > b2 > a
- has lots of b1 activity - increasing myocardial contractility and CO
- positive inotrope at low doses and chronotrope at higher doses
- prolonged therapy may result in down regulation of b receptors
- use for acute treatment of severe heart failure
20
Q
Phenylephrine
A
- sympathomimetic drug - adrenergic agonist
- a1 > a2»_space; b (little effect on heart)
- less potent but longer lasting then norep and ep
- used in cold medicine as decongestant because less mucosal flow
- a1 agonist
21
Q
Ephedrine
A
- sympathomimetic drug - adrenergic agonist
- a1 > a2»_space; b
- releases endogenous norepi
- onset 5 minutes and lasts 10-15 min
- can give bolus injection
- stimulates a1 and b1 receptors
22
Q
Phenylproponolamine
A
- sympathomimetic drug - adrenergic agonist
- a1 > a2»_space; b
- used to treat urinary incontinence in female dogs by increasing the tone of urethral sphincter via a1 activity.
- slow acting and requires multiple doses per day
- a1 agonist
23
Q
Xylazine **
don’t know yet
A
- sympathomimetic drug - adrenergic agonist
- a2 > a1»_space; b
- large impact on bp
24
Q
Detomidine**
don’t know yet
A
- sympathomimetic drug - adrenergic agonist
- a2 > a1»_space; b
- large impact on bp
25
Medetomidine **
| don't know yet
- sympathomimetic drug - adrenergic agonist
- a2 > a1 >> b
- large impact on bp
26
dexmedetomidine **
| don't know yet
- sympathomimetic drug - adrenergic agonist
- a2 > a1 >> b
- large impact on bp
27
romifidine
| don't know yet
- sympathomimetic drug - adrenergic agonist
- a2 > a1 >> b
- large impact on bp
28
Albuterol
- sympathomimetic drug - adrenergic agonist
- b2 > b1 >> a -- b2 agonist
- aerosol route used for acute bronchoconstriction. --> bronchodilator!
- fast acting
- dont use chronically because it down regulates b receptors
29
Clebuterol **
- sympathomimetic drug - adrenergic agonist
- b2 > b1 >> a -- b2 agonist so good for bronchodilation and growth promotion
- can be oral or injectable for horses
- great bronchodilator (good for horses with heaves), inhibits uterine contractions (good for calving) and converts fat to muscle
- Banned for food producing animals because when in food it can cause toxicity in humans!
30
Ractopamine **
- sympathomimetic drug - adrenergic agonist
- b2 > b1 >> a --b2 agonist
- growth promotion put in food for swine and beef cattle.
- increases weight gain and fed efficiency with more muscle and less fat on carcass -- get this by breaking down fat and increasing blood flow so allowing muscle to grow
- not a major public safety concern
31
Zilpterol **
| don't know yet
- sympathomimetic drug - adrenergic agonist
| - b2 > b1 >> a
32
Prazosin
- sympatholytic drug -adrenergic antagonist
- a1 >>>>a2 --a1 antagonist
- little effect on heart rate
- decreases urethral sphincter tone (make sure there isn't a urethral blockage)
- decreases high blood pressure by causing peripheral vasodilation
- used when an animal has an adrenal medulla tumor causing over secretion of norepi and epi
33
Phenoxybenzamine
- sympatholytic drug -adrenergic antagonist
- a1 > a2 --a1 antagonist
- little effect on heart rate
- decreases urethral sphincter tone (make sure there isn't a urethral blockage)
- decreases high blood pressure by causing peripheral vasodilation
- used when animal has an adrenal medulla timor causing over secretion of norepi and epi
34
Tolazoline
- sympatholytic drug -adrenergic antagonist
- a2 >>a1 -- a2 antagonist
- used to reverse sedation or overdose of a2 agonist
35
Yohimbine
- sympatholytic drug -adrenergic antagonist
- a2 >>a1 --a2 antagonist
- used to reverse sedation or overdose of a2 agonist
36
Atipamezole
- sympatholytic drug -adrenergic antagonist
- a2 >>a1 --a2 antagonist
- used to reverse sedation or overdose of a2 agonist
37
Amlodipine
- direct arterial vasodilator (decreasing after load) because it blocks Ca channels in arterial smooth muscle so there is decreased amount of smooth muscle contraction
- used in cats with hypertension
38
Enalapril **
- indirect vasodilator with ACE inhibitors
- slower acting than nitrates so doesn't cause tachycardia
- inhibits ACE resulting in less angiotension II resulting in arterial vasodilation, decreased fluid retention through decreased ADH and aldosterone release
- may also result in hyperkalemia because decreased aldosterone causes increased Na loss and increased K retained.
- used for heart failure in dogs caused by mitral valve regurgitation or dilated cardiomyopathy
39
Benazepril **
- indirect vasodilator with ACE inhibitors
- slower acting than nitrates so doesn't cause tachycardia
- inhibits ACE resulting in less angiotension II resulting in arterial vasodilation, decreased fluid retention through decreased ADH and aldosterone release
- may also result in hyperkalemia because decreased aldosterone causes increased Na loss and increased K retained.
- used for heart failure in dogs caused by mitral valve regurgitation
- may also be helpful for chronic renal failure (with loss of proteins) because the decreased blood pressure will decrease the globular filtration pressure, causing less protein loss
40
Imidapril **
- indirect vasodilator with ACE inhibitors
- slower acting than nitrates so doesn't cause tachycardia
- inhibits ACE resulting in less angiotension II resulting in arterial vasodilation, decreased fluid retention through decreased ADH and aldosterone release
- may also result in hyperkalemia because decreased aldosterone causes increased Na loss and increased K retained.
- used for heart failure in dogs with mitral valve regurgitation
41
Telmisartan
- indirect vasodilator by blocking angiotension receptors.
- binds to AT-1 receptor, inhibiting the actions of angiotension II and therefore causing vasodilation, excreting Na in urine, reducing aldosterone release and inhibiting inappropriate cell growth
- causes dose dependent decrease in Mean arterial blood pressure
- used for heart failure and hypertension but licensed for chronic renal failure in cats
42
Digoxin
- positive inotropic drug and negative chorontropic
- blocks the Na/K pump so there is a build up of Na inside the cells and an increase of K outside of the cell. With the increased Na inside the cell, it is used for the Na/Ca pump, which results in more Ca inside the cell. This increased Ca causes increased strength of contraction.
- also acts as a negative chorotropic drug because it slows the electrical impulse through the AV node so it takes longer for the heart to depolarize and contract.
- net result: heart pumps slower but more efficiently, decreasing the workload
- note: all animals tend to metabolize this drug differently and there is a small therapeutic window. Also, many drugs and clinical interactions alter the drugs metabolism in the body, possibly making it ineffective or toxic.
- hypokalemia and hypercalcemia both increase the digoxin effect
- used with heart failure or atrial fibrillation
43
Pimobendan **
- positive inotrope because it causes myocardial cells to be more sensitive to Ca, causing an increased contraction with same amount of Ca and similar amount of 02 demand.
- also a vasodilator because it inhibits phosphodiesterase III and V (which are normally responsible for vasoconstriction). It affects both arterial and venous (therefore preload and after load) vasodilation
- very safe drug, which a large safety margin
44
Furosemide **
- acts on the loop of Henle by inhibiting Na/K/2Cl transporter in the thick ascending limb. Furosemide binds to Cl which inhibits the whole transporter
- decreases the amount of Na and Cl getting reabsorbed (therefore it stays in the tubule)
- Na can get reabsorbed in the distal tubule but it overwhelms the tubule so it is unable to absorb all of it...more water stays in the tubule because of the excess Na
- there is a risk of hypokalemia because in the collecting duct the Na/K transporter transports more Na into the blood and more K leaves the blood
- there can be a decrease in reabsorption of Mg and Ca because there is no Cl moving into the blood so Mg and Ca don't follow it from the tubule
- there is also an increased renal prostaglandin production, which causes vasodilation, increasing the amount of filtrate produced and further inhibiting Na/Cl reabsorption
- fxn: acute relief of severe edema because decreasing plasma volume. Can be used chronically but needs to be monitored
45
Spironolactone
- blocks the aldosterone receptors in the principle cell so there is decreased production of Na channels in the collecting duct...this causes less Na reabsorption and therefore more excretion of Na and water
- "potassium sparing" because less Na being reabsorbed so there is less K being secreted into the urine
- slow onset
- can be used with furosemide, but try using furosemide first and then if too much K loss then use this as well
- fxn: when aldosterone is a problem in heart failure because it is causing too high of blood pressure
46
Mannitol
- osmotic diuretic
- there is an increased osmolarity of the filtrate compared to the plasma causing water to move into the filtrate out of the plasma and consequently it is excreted.
- happens primarily in loop of hence
- more water is being excreted than Na
- IV administration only and typically for emergencies only
47
Nitrates
- direct vasodilator used for emergencies
- secondary messenger pathway with nitric oxide causing an increase in cGMP, which causes a decrease in smooth muscle contraction in both venous and arterial blood vessels --> vasodilation
- reduces both preload and after load (preload a little bit more)
- can develop a tolerance with chronic use
- used in heart failure!
48
Nitroglycerin
- topical nitrate used on ears
| - dont give orally because it will get metabolized before it is absorbed
49
Sodium nitroprusside
- longer lasting nitrate than nitroglycerin
- only used IV and only for emergencies
- watch out for hypotension
50
Hydralazine
- arterial vasodilator, therefore reduces after load
- thought to decrease Ca levels in smooth muscle, decreasing muscle contraction
- can cause significant hypotension or reflex tachycardia
- fxn: used for left AV valve insufficiency or hypertension
51
Dopamine
- positive inotrope
- used in emergencies
- activates a and b and dopamine receptors to increase contractility of heart
- administered IV and short half life
52
Bypyridines
- positive inotropes
- increases intracellular Ca by inhibiting the phosphdiesterase. Inhibiting the phosphodiesterase causes less cAMP being converted so there is more in the cell to active protein kinase, which results in the phosphorylation of Ca channel so it stays open longer and there is more Ca inside the call causing an increase in contraction
- used IV for emergencies
- also causes arterial and venous vasodilation
53
Quinidine - not used in dogs, still used in horses
| Procainamide
- class 1a anti-arrythmic drug
- decrease speed of heart rate and cardiac cell excitability
- prolonging the refractory period, the depolarizing phase and the repolarizing phase all by decreasing the amount of Na entering the cell
- used for tachycardia and for ventricular arrythmias
- in abnormal and normal tissue
54
Lidocaine (IV)
Tocainide -oral, longer duration
Phenytoin
- class 1b anti-arrythmic drugs
- there is a prolonged depolarization but the refractory period isn't as prolonged because the repolarization is accelerated
- used for tachycardia and ventricular arrythmias
- slows down heart rate and excitability
- in abnormal tissue
55
propranolol
- class 2 anti arrhythmic - b blocker but it is the least specific one used. the b2 antagonist component causes bronchoconstriction --> especially in cats
- with b1 component, it slows down heart rate by slowing down the speed of SA spontaneous depolarization
- used with tachycardias, especially when they are worsened by sympathetic stimulation
56
atenolol
| metoprolol
- class 2 anti arrhythmic - b blocker
- causes overall slowing of down heart rate because there is slower spontaneous depolarization in SA node
- used with tachycardias, especially when they are worsened by sympathetic stimulation
57
Carvedilol
- class 2 anti arrhythmic - b blocker
- both b1 and b2 and a1 antagonist so causes slowing down of heart rate and vasodilation
- used with tachycardias, especially when they are worsened by sympathetic stimulation
58
Amiodarone
Sotalol
Bretylium
- type 3 antiarrhythmics - K channel inhibitors
- decreased amount of K leaving the cells so it prolongs the refractory period and repolarization phase
- used for refractory ventricular tachycardias
59
Verapamil
- class 4 anti arrhythmic - ca channel inhibitor
| - has most of its effect on strength of contraction (negative inotrope) and moderate effects on heart rate
60
Diltiazam
- class 4 anti-arrhythmic - Ca channel inhibitor
- little inotrophic effect, more effective with supraventricular arrhythmias
- used for atrial tachycardias and hypertrophic cardiomyopathy in cats
61
Amlodipine
- class 4 anti-arrhythimic - Ca channel inhibitor
| - less chronotropic and inotrophic effect but more vasodilation
62
Hyrdochlorothiazide
| Chlorothiazide
- thiazide diuretic
- used for chronic diuretic therapy but isn't as potent as furosemide
- inhibits the Na/Cl channel on the distal tubule causing decreased Na reabsorption and therefore excretion...also increased water excretion
63
Acetazolamide
- carbonic anyhydraze inhibitors
- there is less H produced within the cell so there is less H available to exchange with Na in Na/H exchanger on the lumen side of the cell so Na stays in the tubule and joins with HCO3 causing water the move into the tubule and excreted
- used for glaucoma therapy
64
Acepromazine
- tranquilizer
- if used alone it is a mild sedative but also used for preanesthetic sedation
- not an analgesic, but it reduces anxiety so it will help the analgesics work
- slow to work, even when given IV (10-20 min)
- may have mild hypotension side effect
65
Butyrephones
- tranquilizer used for pigs
| - similar to acepromazine but has some unpredictable side effects
66
Benzodiazepines
- sedative, anxiolysis, anticovulsant, spinal-cord mediated muscle relaxation, anterograde amnesia
- not a reliable sedative when used alone - it may cause an excitatory phase when given IV
- used to treat seizures
67
Diazapam
- sedative
- highly lipid soluble, long duration of action
- stings when given IM so normally given IV
- can cross the placental barrier and will reach the young in higher concentrations higher than the mother so don't give during a C section
68
Midazolam
- sedative
- 2-3 times more potent than diazepam
- slow onset time (1-6 min)
- highly lipid soluble when injected
- can be given transmucosally and IM
69
Flumazenil
- reversal
- antagonist to all benzodiazepines
- helps general CNS arousal and increases muscle tone back to normal
- good to use with exotics or in a C section
- action lasts 30-6- min and can be given IV or IM
70
Phenobarbital
- barbiturate
- was used as long lasting anesthetic but was a poor analgesic and muscle relaxant and recoveries are long and unpleasant
- was used to control seizures but now propofol is used
- good sedative when it was given as an infusion
- now only available as an euthanasia solution
71
Thiopental
- barbiturate
- shelf life up to 6 weeks once the solution is mixed
- reliable anesthetic drug with one dose and a reasonable recovery time
- if give multiple doses then there could be an accumulation and a long recovery time
72
Propofol
- onset in 40-90 seconds and lasts 5-10 minutes
- good for infuse with only some accumulation
- little hang over effect so there is fast recovery
- not irritating if accidentally given into tissue
73
Alfazalone
- onset 15-45 seconds ad lasts 5-10 minutes
- reliable anesthetic
- longer shelf life than propofol
- rapid recovery through redistribution, rapid metabolism and litter hang over effect
- little accumulation with infusion or repeat bolus
74
Etomidate
- dissolved in propylene glycol -> can cause hemolysis
- enhances GABA action
- onset 15-45 seconds, lasts 3-12 min
- excitatory side effects
- no analgesia
- painful on injection
75
Ketamine
- used IM, SC, IV, IP
- onset 30-90 seconds and lasts 10-20 min
- recovery has 'emergence delirium' which is when auditory and visual stimuli are disturbed during recovery
- usually combined with other drugs because of muscle rigidity
- used for induction, maintenance and analgesia
- elimination half life for dogs is 60 min and for cats 80 min
76
Tiletamine
- longer acting then ketamine
- can cause convulsions in dogs at high doses
- Sx anesthesia for cats and dogs
- long hang over effect in cats and dogs
- used for zoo animals and wild life IM route
- not available in Canada
77
Guiaifenesin
- only used in large animals
- causes skeletal muscle relaxation
- some narcosis and little analgesia
- not complete anesthesia so don't use alone for Sx
- used as a premed in horses (so you can decrease dose of ketamine) or for casturation as a sole anesthetic
78
Isoflurane
- inhalant anesthetic
- rapid uptake and eliminator
- gold standard
79
Sevoflurance
- inhalant anesthetic
- less potent than isoflurane
- rapid uptake and eliminator
- potent bronchodilator
80
Desflurane
- anesthetic inhalant
- requires an expensive heated, pressurized vaporizer
- associated with tachycardia, hypertension
- unlikely to enter vetmed
81
Nitric Oxide (NO)
inhalation anesthetic
- not potent but very rapid uptake and elimination
- safe to give high concentrations of it but need to still give O2!
- used more for analgesic properties instead of anesthetic properties
- no effects on liver and kidney function but causes bone marrow suppression
82
Doxapram
- respiratory stimulant because it directy stimulates the respiratory centres without stimulating the other centres in the brain
- increases tidal volume and resp rate
- can be given IV,IM or buccal
- immediate onset and lasts 1-2 minutes
- also stimulates the vasomotor centre to increase blood pressure (sympathetic activity)
- increases plasma catecholamines
83
Succinyl Choline
- used to help place endotracheal tube
- fast onset and lasts 1-3 min
- can be used with euthanasia drugs to prevent paddling movements in horses
- completes with ACh keeping the channel open stimulating muscle contraction before flaccid paralysis
84
Atracurium
- not broken down by liver, instead it is metabolized by plamsa cholinesterase's
- onset 1-3 min and lasts 20 min
- competitive inhibition with ACh so the channels don't open so Na cannot enter, causing flaccid paralysis
