mod 16

Question 1

3 endogenous adrenergic neurotransmitters, which are synthesized from tyrosine, belong to the chemical group catecholamines

Answer 1

(norepinephrine, epinephrine and dopamine)

Question 2

is the prototype adrenergic stimulant

Answer 2

epinephrine

Question 3

The other adrenergic stimulants may have some or all of the action of epinephrine (EP).

• Their effects are

Answer 3

not different in quality but only in
intensity

Question 4

Epinephrine has five major effects:

Answer 4

• (1) peripheral excitatory effects (vasoconstriction,
mydriasis, mucoid and thick salivation)
• (2) peripheral inhibitory effects (vasodilation,
relaxation of gut smooth muscles, bronchodilation)
• (3) cardioexcitatory effects
• (4) metabolic effects (hyperglycemia, hyperlipidemia, increased blood lactic acid)
• (5) CNS effects (transient respiratory stimulation, wakefulness, anxiety)

Question 5

True or False

•Drugs acting on the sympathetic domain of the
autonomic nervous system may increase or
decrease adrenergic functions.

•They may or may not be catecholamines

Answer 5

True

Question 6

in 1948 investigated the potency of the three
cateholamines– norepinephrine (NE), epinephrine (EP), and isoproterenol (IS).

Answer 6

Alquist

Question 7

Two orders of potency is observed:

Answer 7

• EP > NE > IS in – arterioles - alpha receptors are involved
• IS > EP > NE - heart and bronchi - beta receptors

Question 8

beta receptors are of 3 subtypes

Answer 8

beta 1 (in the heart)
beta 2 (blood vessels, liver, bronchi)
beta 3 (adipose tissues)

Question 9

these have been developed and are used clinically for each of the Beta subtypes

Answer 9

agonists and antagonists

Question 10

2 subtypes of alpha receptors

Answer 10

alpha 1 receptors (present in postsynaptic fibers)
alpha 2 receptors (present in both pre-synaptic and post-synaptic fibers)

Question 11

mediate dilation of the renal, coronary mesenteric and cerebral arterioles.

Answer 11

dopamine receptors

Question 12

may also act on alpha and beta receptors but its affinity to these receptors is lower than those of the other endogenous catecholamines

Answer 12

dopamine

Question 13

stimulates both alpha and beta receptors

Answer 13

epinephrine (adrenaline)

Question 14

mainly an alpha stimulant

Answer 14

norepinephrine (levarterenol, noradrenaline)

Question 15

pure alpha stimulants

Answer 15

Phenylephrine and Methoxamine

Question 16

pure beta stimulants

Answer 16

isoproterenol and methoxyphenamine

Question 17

specific beta2 adrenergic stimulants

Answer 17

metaproterenol, albuterol, terbutaline

Question 18

specific alpha2 adrenergic stimulants

Answer 18

clonidine, oxymethazoline, xylazine, medetomidine, detomidine

Question 19

acts directly on beta1 receptors in the heart

Answer 19

dopamine

Question 20

on specific dopamine receptors in the CNS, mesenteric, cerebral and renal arterioles.

(since it mediates their dilation)

Answer 20

dopamine

Question 21

It leads to an increase in cardiac contractility and cardiac output with little change in heart rate or blood pressure.

Answer 21

dopamine

Question 22

indicated in cases of acute or chronic congestive heart failure and shock unresponsive to other methods

Answer 22

Dopamine

Question 23

act selectively on beta1 receptors

used specifically for cardiac stimulation

Answer 23

dobutamine

Question 24

it is useful for short-term increase in cardiac output in conditions of shock, congestive heart failure and cardiomyopathy

Answer 24

dobutamine

Question 25

The other directly acting sympathomimetics are usually components of nasal decongestants or ophthalmic vasoconstrictors. Examples are:

Answer 25

• Propylhexedrine (BenzedrexR) – nasal inhaler • Tuaminoheptane (TuaminR) – nasal inhaler • Naphazolene– (PrivinR) – nebulizer, nasal solution, ophthalmic solution • Tetrahydrozoline (VisineR) – ophthalmic solution; (TyzineR) – nasal solution • Oxymethazoline (AfrinR) – nasal solution • Xylomethazoline (OtrivinR) – nasal solution • Phenylpropanolamine

Question 26

equal in potency to ephedrine but with much less CNS action:

Answer 26

phenylpropanolamine

Question 27

used as oral treatment for nasal and sinus congestion;

Answer 27

phenylpropanolamine

Question 28

It is useful in the treatment of urinary incontinence in the dog

Answer 28

phenylpropanolamine

Question 29

usually in combination with an antihistamine drug.

Answer 29

phenylpropanolamine

Question 30

Increases the discharge of NE from the varicosities of nerve terminals

Answer 30

indirectly acting adrenergic agents

Question 31

readily enters the CNS and stimulates mood and alertness and depresses appetite

Answer 31

amphetamine

Question 32

Its effects are mediated through increasing the discharge of norepinephrine from varicosities

Answer 32

amphetamine

Question 33

replace NE in the varicosities

Answer 33

Amphetamine and its derivatives

Question 34

Large doses of amphetamine can induce

Answer 34

hallucinations, violent behavior and psychoses in human.

Question 35

is similar to amphetamine but with greater central than peripheral effects

Answer 35

metamphetamine

Question 36

has an action resembling that of ephedrine but lacks CNS stimulant activity (can pass poorly across the blood-brain barrier)

Answer 36

hydroxyamphetamine

Question 37

It is used to treat hypotensive state; but principally used as mydriatic (dilates pupils)

Answer 37

hydroxyamphetamine

Question 38

ephedrine is resistant to these enzymes

Answer 38

monoamine oxidase (MAO) catechol-O-methyltransferase (COMT)

Question 39

• Affects both beta and alpha adrenergic receptors • It enters the brain

Answer 39

ephedrine

Question 40

ephedrine is commonly used as a

Answer 40

bronchodilator, cardiac stimulant, mydriatic, and CNS stimulant

Question 41

like amphetamines, it causes the release of NE from sympathetic neurons

Answer 41

ephedrine

Question 42

other name of pseudoephedrine

Answer 42

D-Isoephedrine

Question 43

is a stereoisomer of ephedrine

Answer 43

pseudoephedrine

Question 44

has both direct and indirect actions

Answer 44

metaraminol

Question 45

Its overall effect is similar to that of norepinephrine but much less potent and more prolonged

Answer 45

metaraminol

Question 46

principal use of metaraminol

Answer 46

treat hypotensive states in humans

Question 47

10 clinical uses of adrenergic stimulant

Answer 47

• As adjunct to local anesthesia • As hemostatic • As mydriatic • In anaphylactic reactions • As bronchodilator • For treatment of local skin allergy • As decongestant • For diagnosis of heaves in horses • For treatment of cardiac arrest • For treatment of hypertensive conditions

Question 48

are used in human and veterinary medicine to treat pheochromocytoma

Answer 48

phenoxybenzamine and phentolamine

Question 49

a tumor of adrenal medulla that results in a massive increase in the level of circulating catecholamines

Answer 49

pheochromocytoma

Question 50

in dogs and cats, it is used to relax the internal urinary bladder sphincter in cases of reflex dyssynergia.

Answer 50

phenoxybenzamine

Question 51

in horses, it is used in reducing alpha-adrenergic induced arterial spasm in acute laminitis

Answer 51

phenoxybenzamine

Question 52

causes arterial and venous vasodilation without changes in heart rate or cardiac output

Answer 52

prazosin

Question 53

prazosin is used to

Answer 53

decrease blood pressure in patients with systemic hypertension decrease pulmonary edema in cases of congestive heart failure

Question 54

aside from partially blocking alpha receptors, also directly stimulate smooth muscles in many organs.

Answer 54

ergot alkaloids ergonovine, ergocristine, ergocryptine

Question 55

Clinical applications of ergot alkaloids in humans include

Answer 55

treatment of Parkinson’s disease, migraine, and postpartum hemorrhage

Question 56

examples of phenothiazine and butyrophenone

Answer 56

chlorpromazine, acepromazine, and haloperidol (block alpha adrenergic receptors)

Question 57

Idazoxan, Tolazoline, Atipamezole and Yohimbine block what receptors?

Answer 57

specifically block alpha2 adrenergic receptors

Question 58

can reverse the xylazine-induced sedation and analgesia in animals

Answer 58

yohimbine

Question 59

pharmacological effects of alpha-adrenergic blockers

Answer 59

- They have little effect on resting blood pressure - Alpha-blockers have little effect on the gastrointestinal tract • Patients treated with an alpha-adrenergic blocker have a tendency for postural hypertension due to loss of compensatory mechanism, which is dependent upon sympathetic tone mediated by alpha receptors. • Postural hypotension is specifically prominent when there is a massive release of epinephrine, when epinephrine is concurrently administered. This is a manifestation of the **epinephrine reversal effect.**

Question 60

Patients treated with an alpha-adrenergic blocker have a tendency for ____ ____ due to loss of compensatory mechanism, which is dependent upon sympathetic tone mediated by alpha receptors.

Answer 60

postural hypertension

Question 61

is specifically prominent when there is a **massive release of epinephrine**, when epinephrine is concurrently administered this is a manifestation of?

Answer 61

postural hypotension **epinephrine reversal effect**

Question 62

Clinical uses of alpha-adrenergic blockers

Answer 62

- The alpha-adrenergic blockers are sometimes used in reversing compensatory vasoconstriction in cardiovascular shock that may lead to further decrease in tissue perfusion. - They should be given in conjunction with fluid replacement. - They are also used to overcome the effect of excessive epinephrine in case of catecholamine-secreting tumor of the adrenal medulla (pheochromocytoma). - Surgical removal of the tumor is more rational treatment.

Question 63

is a non-selective beta-adrenergic blocker

Answer 63

propanolol

Question 64

propanolol is used in dogs and cats in treatment of

Answer 64

atrial fibrillation, ventricular premature contractions and arrhythmias caused by digitalis toxicity, systemic hypertension, and hypertrophic cardiomyopath

Question 66

Its use in large animals is restricted to the management of tachycardia in the horse

Answer 66

propanolol

Question 67

are selective beta1 blockers

Answer 67

atenolol and metoprolol

Question 68

they are preferred drugs in patients with pulmonary disease

Answer 68

atenolol and metoprolol

Question 69

and are useful in the management of supraventricular arrhythmias, ventricular premature contractions, systemic hypertension and hypertrophic cardiomyopathy (in what animal)?

Answer 69

atenolol and metoprolol cats

Question 70

botuxamine is an example of what blocker

Answer 70

selective beta2 blocker

Question 71

Pharmacological effect of Beta-adrenergic Blockers

Answer 71

- They cause **cardiac depression**, and therefore may aggravate heart failure. - By blocking beta2 adrenergic receptors in bronchi, they may cause **bronchoconstriction**

Question 72

Clinical Uses of Beta-adrenergic Blockers

Answer 72

- The beta-blockers are drugs of choice for **treatment of essential hypertension** in human. - Other uses include **reversing digitalis-induced cardiac arrhythmias** - **treatment of obstructive cardiomyopathy, a rare disease of dogs and cats** - **block the effect of excessive epinephrine in pheochromocytoma**