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Pharmacology 1 choefsho > Drugs acting on the sympathetic NS > Flashcards

Drugs acting on the sympathetic NS Flashcards

1
Q

This alpha-1 antagonist (sympatholytic) is available as oral capsules for humans, but is commonly used to treat small animals. It dilates arterioles and veins and is used to treat urinary retention due to urethral hypertonicity (adjunctive treatment of congestive heart failure or systemic or pulmonary hypertension)

  1. Phenoxybenzamine (Dibenzyline)
  2. Propanolol (Inderal)
  3. Atenolol (Tenormin)
  4. Metoprolol (Lopressor)
  5. Prazosin (Minipress)
A
  1. Prazosin (Minipress)

(less reflex tachycardia and activation of RAA system than hydralazine; compared to phenoxybenzamine, it may have a slightly greater effect (faster onset of action) to treat urinary retention)

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2
Q

This indirect acting sympatholytic is used in human medicine to treat hypertension by blocking the release of NE.

  1. Guanethidine (Ismelin)
  2. Reserpine (Serpalan)
  3. Alpha-methyl dopa
A
  1. Guanethidine (Esmelin)
    * (available in the UK, but not the US)*
    * (img: bottom arrow)*
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3
Q

This mixed sypmathomimetic causes an indirect increase in NE release (mainly) and also direct alpha-1 and beta activation. It increases blood pressure (vasoconstriction and cardiac stimulation), bronchodilates, contracts the urinary sphincter, and causes mydriasis.

  1. Phenylpropanolamine (PPA, Proin)
  2. Ephedrine/Pseudoephedrine (Ephedra)
A
  1. Ephedrine/Pseudoephedrine (Ephedra)

(less specific in what it does compared to PPA; products with ephedrine/pseudoephedrine has been OTC in the USA since 2005; people used to use it for weight loss)

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4
Q

T or F. Epinephrine can be given IV, IM, SQ, inhaled, and orally.

A

False, not orally! (mainly IV)

(remember, catecholamines are poorly absorbed after oral administration > high first-pass effect)

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4
Q

This mixed sympathomimetic causes an indirect increase in NE in the neck of the bladder/urethera (mainly) and also works as a direct alpha-1 agonist. It is availabe for humans (tabs, ER, oral solution), but used in small animals (mainly dogs) to treat urinary incontinence due to urethral sphincter hypotonus.

  1. Phenylpropanolamine (PPA, Proin)
  2. Ephedrine/Pseudoephedrine
A
  1. Phenylpropanolamine (PPA, Proin)
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4
Q

________________ is a legal herb that causes increased blood pressure, bronchodilation, and urinary sphincter contraction (like ephedrine); however, in the USA it cannot be marketed as a diet aid supplement

A

Ma huang

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4
Q

This alpha antagonist (sympatholytic) is available as oral capsules for humans (10mg), but is used in small animal medicine for urinary retention due to urethral hypertonicity and pheochromacytoma.

  1. Phenoxybenzamine (Dibenzyline)
  2. Propanolol (Inderal)
  3. Atenolol (Tenormin)
  4. Metoprolol (Lopressor)
  5. Prazosin (Minipress)
A
  1. Phenoxybenzamine (Dibenzyline)
  • Non-specific alpha antagonist: binds irreversibly to the receptors and lasts for the lifetime of the receptors (3-4 days)
  • Takes days to see the effect
  • Treats urinary retention due to urethral hypertonicity by relaxing the internal sphincter (may be combined with other agents [muscle relaxants], such as Diazepam)
  • Treats Pheochromocytoma (tumor of the adrenal medulla); prior to surgery to treat associated hypertension
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5
Q

T or F. Epinephrine (catecholamine) activates all adrenergic receptors (alpha-1, alpha-2, beta-1, beta-2).

A

True

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5
Q

What is the range of dilution for epinephrine?

  1. 1 : 10 to 1 : 100
  2. 1 : 100 to 1 : 1,000
  3. 1 : 1,000 to 1 : 10,000
  4. 1 : 10,000 to 1 : 100,000
A
  1. 1 : 1,000 to 1 : 10,000 (dilute)

Remember the math, 1 : 1,000 = 1/1,000 = 0.001 = 0.1% = 0.1g/100mL = 100mg/100mL = 1mg/mL

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5
Q

This sympatholytic is used orally (injectable available too) to treat tachyarrhythmias (supraventricular), feline hyperthyroidism, and methylxanthine (chocolate) toxicosis.

  1. Cavedilol
  2. Propanolol (Inderal)
  3. Atenolol (Tenormin)
  4. Metoprolol (Lopressor)
  5. Bisoprolol
A
  1. Propanolol (Inderal)
  • Nonspecific beta-antagonist (may be inverse agonist)
  • Decrease SA firing (bradycardia) and AV conduction, decreases cardiac output and myocardial oxygen demand, increases airway resistance
  • Also has membrane stabilizing effect (neurons and muscles)
  • Thyroxine increases chronotropy and inotropy, so we get a hypertrophic heart with hyperthyroidism
  • Methylxanthine toxicosis > increases cardiovascular status > less perfusion
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6
Q

What effects does Phenylephrine (Neo-synephrine) have (choose all that apply)?

  1. Vasopressor immediately IV, lasts
  2. Reflex bradycardia
  3. Tachycardia
  4. Used in dogs and cats to treat hypotension
  5. Used in dogs and cats to treat hypertension
A
  1. Vasopressor immediately IV, lasts 2. Reflex bradycardia
  2. Used in dogs and cats to treat hypotension
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7
Q

What are the 2 different types of sympatholytics?

A
  • Direct acting (alpha and beta antagonists)
  • Indirect acting
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7
Q

Since NE does not act on beta-2 receptors (bronchodilation and vasodilation), what effects, will you mainly see for NE? (choose all that apply)

  1. More vasoconstriction
  2. Increased afterload
  3. Bronchodilation
  4. No vasodilatory effects counteracting the alpha-1 mediated vasoconstriction (strong baroreceptor response and decrease heart rate/contractility in spite of beta-1 effects)
A
  1. More vasoconstriction
  2. Increased afterload
  3. No vasodilatory effects counteracting the alpha-1 mediated vasoconstriction (strong baroreceptor response and decreased heart rate/contractility in spite of beta-1 effects)
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7
Q

Which is not a non-selective beta agonist?

  1. Salmeterol
  2. Ractopamine
  3. Zilpaterol
A
  1. Salmeterol is a selective beta-2 agonist

(non-selective means that they are not selective for beta-1 or beta-2; sometimes called a beta-3 agonist)

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7
Q

Non-selective beta agonists Ractopamine (Paylean) and Zilpaterol (Zilmax) are “partitioning agents”, which mean they (choose all that apply):

  1. Increase the rate of weight gain
  2. Increase feed efficiency
  3. Increase carcass leanness in food animals (increase deposition of muscle rather than fat in late finishing animals)
  4. All of the above
  5. False, they are not partitioning agents!
A
  1. All of the above!
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7
Q

What type of sympatholytics are there?

A
  • Direct-acting
    • Alpha antagonist
    • Beta antagonist
      • Non-selective
      • Selective
  • Indirect-acting
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9
Q

__________ is a co-transmitter that may be responsible for some of the fast sympathetic responses with NE acting a bit later; it is common in vesicles containing NE).

A

ATP

Other co-transmitters include:

  • Neuropeptide Y
  • VIP (vasoactive intestinal polypeptide)
  • GnRH (gonadotrophin releasing hormone)
  • GABA (Gamma-Aminobutyric Acid)
  • Serotonin (5-HT)
  • Dopamine
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11
Q

This sympatholytic readily crosses the BBB, has a significant first-pass effect (oral bioavailability in dogs 2.27%) with a short half life of 1-2 hours. It will mainly be excreted in the urine as metabolites.

  1. Cavedilol
  2. Propanolol (Inderal)
  3. Atenolol (Tenormin)
  4. Metoprolol (Lopressor)
  5. Bisoprolol
A
  1. Propanolol (Inderal)
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12
Q

This beta-2 agonist causes vasodilation in skeletal muscles, uterine relaxation, and increases distal limb perfusion. It can also be used in cattle as a tocolytic for cesarean operations, fetal manipulation in dystocia, or embryo transplants.

  1. Clenbuterol (Ventipulmin)
  2. Terbutaline (Brethine)
  3. Albuterol/Salbutamol (Ventolin, Torpex)
  4. Isoxsuprine (Vasodilan)
A
  1. Isoxsuprine (Vasodilan)

(previously used in horses for navicular disease; not used much in VetMed)

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13
Q

T or F. Methyldopa is a false substrate drug that produces a different product than norepinephrine to prevent the production of that neurotransmitter.

A

True

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14
Q

T or F. Dopamine can cause necrosis if given extravascularly.

A

True

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16
Q

Adrenergic agonists are generally used for which of the following? (choose all that apply)

  1. To slow the heart
  2. Heart disease
  3. Anaphylactic reactions
  4. Obstructive airway disease (asthma)
  5. Reversal of alpha-2 sedation
  6. Sedation and analgesia
A
  1. Heart disease (epinephrine, beta-1 agonist)
  2. Anaphylactic reactions (epinephrine)
  3. Obstructive airway disease (beta-2 agonists)
  4. Sedation and analgesia (alpha-2 agonists)
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16
Q

This selective beta-2 agonist is veterinary approved and is available as an oral syrup to treat chronic pulomonary diseases in horses. It can sometimes be used outside the US as an adjunct for treatment of equine dystocia (uterine relaxation from vasodilation to muscles).

  1. Clenbuterol (Ventipulmin)
  2. Terbutaline (Brethine)
  3. Albuterol/Salbutamol (Ventolin, Torpex)
  4. Isoxsuprine (Vasodilan)
A
  1. Clenbuterol (Ventipulmin)

(it is not permitted in food animals; it is also not approved for humans, has been used as a performance enhancer by athletes [vasodilation to skeletal muscles])

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18
Q

This indirect acting sympatholytic is used to calm equines by blocking the uptake of NE into vesicles which reduces the storage of NE and leads to mediator depletion.

  1. Guanethidine (Ismelin)
  2. Reserpine (Serpalan)
  3. Alpha-methyl dopa
A
  1. Reserpine (Serpalan)

  • (used for long-term stall rest)*
  • (img: middle arrow)*
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19
Q

Sympathetic drugs bind to and activate or block _____________ receptors (usually on the post-synaptic membrane).

  1. Adrenergic
  2. Nicotinic
  3. Muscarinic
A
  1. Adrenergic (Alpha-1, Alpha-2, Beta-1, Beta-2 Beta-3)

(Alpha-2 receptors may be presynaptic and inhibitory)

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20
Q

If you inject a drug that you do not want to get absorbed, you can also administer a:

  1. Local vasoconstrictor
  2. Local vasodilator
  3. False, you do not want mix drugs
A
  1. Local vasoconstrictor (e.g. Lidocaine)
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21
Q

T or F. Epinephrine (catecholamine) can be used systemically and locally.

A

True

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21
Q

This sympatholytic is a selective beta-1 antagonist that is similar to Propanolol, but is less lipid soluble, does not cross the BBB as readily, and has a longer half-life (3.2-3.7 hours). It also has less effect on beta-2 receptors in the lungs because it is selective.

  1. Cavedilol
  2. Esmolol (Brevibloc)
  3. Sotalol (Betapace)
  4. Atenolol (Tenormin)
  5. Metoprolol (Lopressor)
  6. Bisoprolol
A
  1. Atenolol (Tenormin)
  • Available as oral tablets for humans
  • Minimal liver metabolism so half will be excreted unchanged in urine, and the rest will be in the feces (better for patients with liver disease than propanolol)
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23
Q

Which of the following is not a selective beta-1 antagonist?

  1. Bisoprolol
  2. Sotalol
  3. Esmolol
  4. Metoprolol
  5. Atenolol
A
  1. Sotalol is a non-selective beta antagonist
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24
Q

This indirect acting sympatholytic reduces the synthesis of NE by blocking DOPA decarboxylase in the NE production pathway (false substrate).

  1. Guanethidine (Ismelin)
  2. Reserpine (Serpalan)
  3. Alpha-methyl dopa
A
  1. Alpha-methyl dopa

  • (sometimes used for hypertension in humans, not typically used in VetMed)*
  • (img: top arrow)*
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26
Q

This sympatholytic is a selective beta-1 blocker available as an injectable and lasts only for 20 minutes so it can be used to test response to beta-blocker.

  1. Cavedilol
  2. Esmolol (Brevibloc)
  3. Sotalol (Betapace)
  4. Atenolol (Tenormin)
  5. Metoprolol (Lopressor)
  6. Bisoprolol
A
  1. Esmolol (Brevibloc)

(it does not cross the BBB; lacks membrane-stabilizing effect)

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27
Q

T or F. Norepinephrine activates all adrenergic receptors (alpha-1, alpha-2, beta-1, beta-2).

A

False! It only activates alpha-1, alpha-2, beta-1

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28
Q

Indirect acting sympathomimetics are generally used for what kind of effects?

A

CNS effects

  • Behavior modification (antidepressants in humans), but have to beware of peripheral side effects!
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29
Q

Match the dopamine dose to its effect:

A. Low dose

B. Medium-low dose

C. Medium-high dose

D. High dose

  1. Beta-1 agonist: positive chronotrope and increased cardiac automaticity
  2. Alpha-1 agonist: vasoconstriction
  3. Dopamine agonist: renal, mesenteric and coronary arteriolar vasodilation
  4. Beta-1 agonist: Positive inotrope
A

A. Low dose - 3. Dopamine agonist: renal, mesenteric and coronary arteriolar vasodilation

B. Medium-low dose - 4. Beta-1 agonist: Positive inotrope (contractility)

C. Medium-high dose - 1. Beta-1 agonist: positive chronotrope (heart rate) and increased cardiac automaticity

D. High dose - 2. Alpha-1 agonist: vasoconstriction

30
Q

Epinephrine is used systemically for (choose all the apply):

  1. Glaucoma
  2. Cardiac arrest
  3. Anaphylaxis/anaphylactoid reaction
  4. Vasopressor (vasoconstriction)
  5. Inotropic infusion
A
  1. Cardiac arrest
  2. Anaphylaxis/anaphylactoid reaction
  3. Vasopressor (vasoconstriction)
  4. Inotropic infusion (positive inotrope increases contractility of the heart)
30
Q

Which of the following are non-adrenergic and non-cholinergic (NANC) transmitters?

  1. Dopamine
  2. Dobutamine
  3. Epinephrine
  4. Serotonin (5-HT)
  5. GABA (gamma-aminobutyric acid)
  6. NO (nitric oxide)
  7. 4, 5, 6 only
  8. 1, 4, 5, 6 only
  9. 1, 2, 4, 5, 6 only
  10. All of the above
A
  1. 1, 4, 5, 6 only
    * (Epinephrine and dobutamine are adrenergic catecholamines)*
  • Dopamine
  • Serotonin (5-HT)- 5- hydroxytrypamine
  • GABA (gamma-aminobutyric acid)- the main inhibitory neurotransmitter in the CNS
  • NO (nitric oxide)- potent vasodilator

(Hey sexy, do you want to lay on my cholinergic or adrenergic receptors? No sir, your garbage ain’t doper than me)

32
Q

Adrenergic antagonists are generally used for which of the following? (choose all that apply)

  1. To slow the heart
  2. Heart disease
  3. Anaphylactic reactions
  4. Obstructive airway disease (asthma)
  5. Vasodilation
  6. Reversal of alpha-2 sedation
  7. Sedation and analgesia
A
  1. To slow the heart (beta-1 blockers)
  2. Vasodilation (alpha-1 blockers)
  3. Reversal of alpha-2 sedation (alpha-2 blockers)
34
Q

CAUTION! Dobutamine can cause:

  1. Similar effects to dopamine
  2. Acute heart failure
  3. Bradycardia
  4. Severe bronchoconstriction
A
  1. Similar effects to dopamine
  2. Acute heart failure
35
Q

In the sympathetic nervous system, the pre-ganglionic neuron releases _______________ onto the ______________ receptor, while the post-ganglionic neuron releases __________________ onto the __________________ receptor.

  1. Norepinephrine, adrenergic, actetylcholine, nicotinic
  2. Norepinephrine, nicotinic, acetylcholine, adrenergic
  3. Acetylcholine, adrenergic, norepinephrine, nicotinic
  4. Acetylcholine, nicotinic, norepinephrine, adrenergic
A
  1. Acetylcholine, nicotinic, norepinephrine, adrenergic

In the sympathetic nervous system, the pre-ganglionic neuron releases ACh onto the nicotinic receptor, while the post-ganglionic neuron releases NE onto the adrenergic receptor.

36
Q

Epinephrine is used locally for (choose all that apply):

  1. Used with local anesthetics (Lidocaine) to vasoconstrict and delay absorption
  2. Treat local hemorrhage
  3. Glaucoma
  4. Inotropic infusion
A
  1. Used with local anesthetics (Lidocaine) to vasoconstrict and delay absorption
  2. Treat local hemorrhage (epistaxis)
  3. Glaucoma
38
Q

All of the following are negative effects of catecholamines, except:

  1. Arrhythmias/tachycardia
  2. Bradycardia
  3. Anxiety, restlessness, tremors
  4. Cerebral hemorrhage
  5. Altered perfusion of kidneys (esp. NE)
  6. Extravasation of NE/Dopamine can cause tissue damage and slough
A
  1. Bradycardia
39
Q

T or F. Ractopamine (Paylean) and Zilpaterol (Zilmax) are non-selective beta agonists that activate beta-1, beta-2 and beta-3 receptors.

A

True, especially beta-3

40
Q

_____________ is a drug that blocks the uptake of norepinephrine into vesicles for storage and causes NE depletion.

  1. Methyldopa
  2. Reserpine
  3. Bretylium
  4. Imipramine
A
  1. Reserpine (causes NE to run out; it is also sometimes used as a sedative in equines)
41
Q

This selective beta-2 agonist is available as tablets or injections (mainly oral) for humans, but is used commonly in small animal practice. It has minimal beta-1 effects and virtually has no alpha effects at typical doses.

  1. Clenbuterol (Ventipulmin)
  2. Terbutaline (Brethine)
  3. Albuterol/Salbutamol (Ventolin, Torpex)
  4. Isoxsuprine (Vasodilan)
A
  1. Terbutaline (Brethine)

(have to be cautious of cardiac patients; the oral bioavailability in equines is <1%

42
Q

T or F. Generally, the more selective a drug is, the fewer adverse effects you will see.

A

True

43
Q

_____________ is a drug that alters uptake of norepinephrine back up by the presynaptic neuron and prevents its break down by Monoamine Oxidase (MAO).

  1. Methyldopa
  2. Reserpine
  3. Bretylium
  4. Imipramine
A
  1. Imipramine
44
Q

Phenylephrine (Neo-synephrine) is a ___________________.

  1. Alpha-1 agonist
  2. Alpha-2 agonist
  3. Beta-1 agonist
  4. Beta-2 agonist
A
  1. Alpha-1 agonist, not used much
45
Q

Dobutamine IV has effects such as (choose all that apply):

  1. Increase coronary, skeletal, renal and mesenteric flow
  2. Mild positive chronotropic effects
  3. Positive inotropic effect
  4. Bronchdilation
  5. Vasodilation
A
  1. Increase coronary, skeletal, renal and mesenteric flow
  2. Mild positive chronotropic effects
  3. Positive inotropic effect

(Bronchodilation and vasodilation are beta-2 effects!)

47
Q

T or F. The effects of dopamine are dose-dependant.

A

True

48
Q

What are the 2 drugs that are direct AND indirect acting (mixed)?

A
  1. Phenylpropanolamine (PPA, Proin)
  2. Ephedrine/Pseuoephedrine
49
Q

Which drugs are direct-acting sympathetic alpha/beta agonists? (choose all that apply)

  1. Catecholamines (epinephrine, norepinephrine, dopamine)
  2. Synthetic catecholamines (dobutamine, isoproterenol, phenylephrine)
  3. Alpha-1 agonists
  4. Alpha-2 agonists
  5. Beta agonists
A
  1. Catecholamines (epinephrine, norepinephrine, dopamine all derived from tyrosine) = EXTREMELY POTENT, narrow therapeutic index!
  2. Synthetic catecholamines (dobutamine, isoproterenol, phenylephrine)
  3. Alpha-2 agonists
  4. Beta agonists
50
Q

CAUTION! What do you have to be cautious of when using selective beta-2 agonists?

  1. Cardiac stimulation, vasodilation, uterine relaxation
  2. Do not use in patients with cardiovascular disease
  3. Nervousness, sweating, muscle tremors, weakness, vomitting
  4. Receptor down-regulation
  5. ARCI class 3 agents- may be prohibited by some equine associations (shows)
  6. All of the above
  7. 2, 3, 5 only
A
  1. All of the above, selective agonists can affect other receptors
  • Cardiac stimulation, vasodilation, uterine relaxation (not good for pregnant animals)
  • Do not use in patients with cardiovascular disease
  • Nervousness, sweating, muscle tremors, weakness, vomitting
  • Receptor down-regulation (tolerance if given chronically)
  • ARCI (Association of Racing Commisioners International) class 3 agents- may be prohibited by some equine associations (shows)
51
Q

T or F. Catecholamines are extremely potent and readily cross the BBB.

A

FALSE, they do not cross the BBB!

(mostly peripheral effects, not central)

51
Q

Match what epinephrine does on specific receptors:

A. Alpha-1

B. Beta-1

C. Beta-2

  1. Bronchodilation, vasodilation
  2. Vasoconstriction
  3. Cardiac contraction
A

A. Alpha-1 - 2. Vasoconstriction (at higher doses)

B. Beta-1 - 3. Increased cardiac contraction

C. Beta-2 - 1. Bronchodilation, vasodilation (esp. at low doses)

B1: imagine how you were when you saw your 1st bee > heart beating hard as hell

53
Q

CAUTION! Which is not a caution when using Phenylpropanolamine (Proin)?

  1. Restlessness
  2. Anorexia
  3. Urine retention
  4. Urinary incontinence
  5. Tachycardia
  6. Hypertension
  7. Tachyphylaxis
A
  1. Urinary incontinence (it is used to treat incontinence)

(Few side effects at usual doses; tachyphylaxis is theoretically possible [mediator depletion] but hasn’t been reported with this usage]

54
Q

All of the following are alpha-2 selective agonists, except:

  1. Isoproterenol
  2. Xylazine
  3. Detomidine
  4. Romifidine
  5. Brimonidine (ophthalmologic)
  6. Dexmedetomidine
A
  1. Isoproterenol is a beta agonist

(alpha-2 drugs have CNS effects)

55
Q

This oral non-selective beta blocker is used to treat ventricular tachyarrythmias (class III antiarrythmic) by prolonging the duration of action potentials and the refractory period.

  1. Cavedilol
  2. Esmolol (Brevibloc)
  3. Sotalol (Betapace)
  4. Atenolol (Tenormin)
  5. Metoprolol (Lopressor)
  6. Bisoprolol
A
  1. Sotalol (Betapace)

(does not have a significant first-pass effect)

56
Q

T or F. Isoxsuprine is a beta agonist.

A

True

56
Q

Which of the following is not an indirect acting sympathomimetic?

  1. Tricyclic antidepressants
  2. Selective serotonin re-uptake inhibitors SSRIs
  3. Monamine oxidase inhibitors MAOI
  4. LSD
  5. Cocaine
  6. Amphetamine
A
  1. LSD
  • Tricyclic antidepressants [Clomipramine (Clomicalm)]
  • Selective serotonin re-uptake inhibitors SSRIs [Fluoxetine (Prozac)]
  • Monamine oxidase inhibitors MAOI [Selegiline (Anipryl)]
    • MAO breaks down NE
  • Cocaine (blocks NE re-uptake)
  • Amphetamine (increases NE release)
57
Q

What are the main ways that the action of catecholamines are terminated?

A
  1. Removal from the site of action
  2. Uptake by pre-synaptic nerve terminals (85%)
  3. Uptake by post-synaptic nerve terminals (5%)
  4. (kidneys ~8%)
58
Q

T or F. Dopamine is given via IV infusion and has a very short half-life.

A

True, but be careful of acute heart failure and shock!

(monitor ECG, ABP: tachycardia, supraventricular arrhythmias, hypo-hypertension)

59
Q

Which of the following sympatholytics are considered class II antiarrhythmics?

  1. Non-selective beta and alpha-1 antagonists
  2. Selective beta-1 antagonists
  3. Non-selective beta antagonists
  4. Selective alpha-2 antagonists
  5. Non-selective alpha-2 antagonists
A
  1. Non-selective beta antagonists = beta blockers (Propanolol, Sotalol, Timolol [opthalmic], Nadolol)
60
Q

After doing its job, norepinephrine dissociates from the receptor and is taken back up mainly by the _________________ neuron, where it is broken down by _____________________.

  1. Presynaptic, Monoamine Oxidase (MAO)
  2. Presynaptic Cholinesterase
  3. Postsynaptic Monoamine Oxidase (MAO)
  4. Postsynaptic, Cholinesterase
A
  1. Presynaptic, Monoamine Oxidase (MAO)

(85% broken down this way)

62
Q

Which is not a selective beta-2 agonist?

  1. Abluterol
  2. Xylazine
  3. Clenbuterol
  4. Terbutaline
  5. Fenoterol
  6. Salmeterol
A
  1. Xylazine is an alpha-2 selective agonist
62
Q

This selective beta-1 antagonist has been used to treat methylxanthine (chocolate) toxicity, but may have less impact on the clearance of the toxin than Propanolol.

  1. Cavedilol
  2. Esmolol (Brevibloc)
  3. Sotalol (Betapace)
  4. Atenolol (Tenormin)
  5. Metoprolol (Lopressor)
  6. Bisoprolol
A
  1. Metoprolol (Lopressor)
63
Q

Isoproterenol is a ______________________.

  1. Alpha agonist (alpha-1 and alpha-2)
  2. Beta agonist (beta-1 and beta-2)
  3. Alpha and beta agonist
  4. Beta-1 agonist
A
  1. Beta agonist (beta-1 and beta-2), not used much
64
Q

Which is used more commonly, epinephrine or norepinephrine?

A

Epinephrine, NE not used much

65
Q

What are the 3 different types of sympathomimetics?

A
  • Direct acting agonists (catecholamines and other direct acting alpha and beta agonists)
  • Indirect acting agonists
  • Mixed (direct and indirect)
66
Q

Now that you know what Propanolol does and what it treats, what are the cautions to look out for?

A
  • Bradycardia
  • Hypotension
  • Bronchospasm
  • Receptor desensitization and upregulation (acute withdrawal exacerbates side effects)
  • Contraindicated with overt heart failure, sinus bradycardia, heart block or bronchospastic lung disease
67
Q

T or F. Catecholamines are poorly absorbed from the respiratory tract, but are readily absorbed after oral administration.

A

False! They are readily absorbed through inhalation or nebulization and are poorly absorbed after oral administration (high first-pass effect) so they are almost always given by injection. SC absorption also sucks, slow if alpha-1 agonist.

68
Q

Dobutamine is a synthetic ________ agonist.

  1. Alpha-1
  2. Alpha-2
  3. Beta-1
  4. Beta-2
A
  1. Beta-1

(good for pump failure)

70
Q

_______________ can be used with Phenylpropanolamine (Proin) for synergistic effects to increase alpha-1 receptors in the internal sphincter.

A

Estrogen

71
Q

Selective beta-2 agonists are primarily used for which of the following?

  1. Vasoconstriction
  2. Positive inotrope
  3. Positive chronotrope
  4. Bronchodilation
A
  1. Bronchodilation; treats asthma/COPD
    * (also may be ‘cilia augmentors’ increasing the beat frequency of airway cilia; generally minimal beta-1 activity at usual doses)*
    * *Think about blood flow to the lung and the ventilation-perfusion (V/Q) relationship; is the amount of air getting to the alveoli matching the amount of blood being sent to the lungs?**
73
Q

Isoproterenol given IV has effects such as (choose all that apply):

  1. Bronchodilation
  2. Vasoconstriction
  3. Increase coronary, skeletal, renal and mesenteric flow (vasodilation)
  4. Mild positive chronotropic effects
  5. Positive inotropic effects
A
  1. Bronchodilation
  2. Increase coronary, skeletal, renal and mesenteric flow (vasodilation)
  3. Mild positive chronotropic effects
  4. Positive inotropic effects

(remember what beta-1 and beta-2 receptors do: B1 what happened to your heart when you saw your 1st bee? )

75
Q

T or F. Phenylephrine is available as injectables, opthalmic, intranasal, liquids, and oral tablets.

A

True, but mainly injectable; not as frequently used in VetMed

(e.g. nasal decongestant for humans)

76
Q

_____________ is a calcium blocker that inhibits the release of norepinephrine.

  1. Methyldopa
  2. Reserpine
  3. Bretylium
  4. Imipramine
A
  1. Bretylium
77
Q

Which of the following is synthesized and stored in vesicles of the terminal axon?

  1. Tyrosine
  2. Dopa
  3. Dopamine
  4. Norepinephrine
  5. Epinephrine
A
  1. Norepinephrine
78
Q

This selective beta-2 agonist is available as an aerosol inhaler (oral available too; human approved) where a clinical response can be seen within 5 minutes and last for 7 hours.

  1. Clenbuterol (Ventipulmin)
  2. Terbutaline (Brethine)
  3. Albuterol/Salbutamol (Ventolin, Torpex)
  4. Isoxsuprine (Vasodilan)
A
  1. Albuterol/Salbutamol (Ventolin, Torpex)
    * (it has a very high pKA (9.3) so it is ionized in blood and tissues, making oral absorption poor but action via inhalation is very good; better effect locally on the area of interest, compared to it reaching the heart)*
  • Salmeterol (Serevent, Advair)
  • Salmeterol + Fluticasone (Steroid)
    • Inflammation is usually what causes bronchoconstriction so the steroids treat the inflammation
79
Q

T or F. Propanolol should be used with caution in patients with hepatic or renal disease, hyperglycemia, and those on digitalis treatment.

A

False, Propanolol should be used with caution in patients with hepatic or renal disease, HYPOglycemia, and those on digitalis treatment.

80
Q

CAUTION! Phenoxybenzamine (Dibenzyline) can cause which of the following side effects?

  1. Hypotension
  2. Miosis
  3. Changes in the intraoccular pressure
  4. Bradycardia
  5. GI signs
  6. All of the above
  7. 1, 2, 3, 5 only
A
  1. 1, 2, 3, 5 only
  2. Hypotension
  3. Miosis
  4. Changes in the intraoccular pressure
  5. GI signs

Also tachycardia; excessive alpha-blockade

81
Q

What drug would you use on a dog with congestive heart failure who has trouble urinating?

A

Prazosin (alpha-1 antagonist)

82
Q

T or F. Dobutamine has a more chronotropic effect than it does an inotropic effect.

A

False, Dobutamine has a more inotropic effect.

83
Q

Norepinephrine vasoconstricts at ______ doses and dopamine vasoconstricts at _______ doses.

  1. Low, low
  2. High, high
  3. Low, high
  4. High, low
A
  1. Norepinephrine vasoconstricts at low doses and dopamine vasoconstricts at high doses.
84
Q

T or F. Propanolol should be used with caution in patients with hepatic and renal disease because it has a significant first-pass effect and it is excreted mainly via urine.

A

True

Pharmacology 1 choefsho (13 decks)

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