Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharm II Unit I > 3 Adrenergic Stimulants > Flashcards

3 Adrenergic Stimulants Flashcards

1
Q

How is NE created?

A

Tyrosine hydroxylated to become I-dopa, which is then decarboxylated to dopamine (DA), which either stays as DA or is hydroxylated to NE (converted to Epi in adrenal medulla)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the rate limiting step in the synthesis of NE?

A

Conversion of tyrosine to I-dopa

This is blocked by metyrosine (Demser)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Drugs such as tyramine and amphetamine only have an effect if noradrenergic innervation is intact. Why?

A

Because they cause or increase the release of NE from the presynaptic terminal. No innervation, no NE to release.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the main mechanism for termination of action of NE?

A

Reputable by the presynaptic terminal

Blocked by many drugs, including antidepressents and cocaine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How can we measure the metabolism of NE and Epi?

A

By evaluating the concentrations of the metabolites VMA and HVA in a 24-hour urine sample

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The sympathetic nervous system has important effects on …

A

Heart and blood vessels

Activated in response to physical activity, stress, and blood loss, to help return to homeostasis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

The effects of sympathomimetic drugs are similar to those of SNS activation:

A

Stimulation of smooth muscle causing constriction of blood vessels in skin, kidneys, and mucous membranes (a1)

Relaxation of blood vessels supplying skeletal muscles (B2)

Stimulation of sweat and salivary glands (a, muscarinic)

Relaxation of smooth muscles in the gut and bronchial tree (B2)

Increase in rate and force of contraction of the heart (B1, B2)

Increased glycogenolysis (B2, B3)

Modulation of insulin, Renin, and pituitary hormones (B1, a)

CNS stimulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Alpha1 receptors are _______ and stimulation leads to …

A

Excitatory - stimulation leads to formation of IP3, increasing Ca2+, and DAG —> activates protein kinase C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Alpha2 receptors are _______ and often found ________ where they act to _______ neurotransmitter release

A

Inhibitory, found presynaptically, reduce NT release

Inhibit adenylyl cyclase and decrease intracellular cAMP (Gi-protein)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the selective agonist for Alpha1 receptors?

A

Phenylephrine

Causes vasoconstriction, increased PVR, esp in small vessels

Causes vasoconstriction in nasal mucosa, decreasing congestion

Dilated pupil —> mydriasis

Causes constriction of the prostate gland

Stimulate pilomotor smooth muscle, causing erection of hair

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the selective agonist for Alpha2 receptors?

A

Clonidine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

NE and Epi have about equal affinity for ____ receptors but Epi has a higher affinity for ____ receptors.

A

B1 for both, B2 for epi

NE has little effect on B2 receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

All subtypes of beta receptor activate adenylyl cyclase through a ___________

A

Gs protein —> increased intracellular cAMP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Selective agonist for B1 receptors?

A

Dobutamine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What do B2 receptors effect?

A

Increase the force and rate of contraction of the heart (positive inotropic and chronotropic effect)

Increase AV conduction velocity and automaticity

Increase renin secretion from kidney

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Selective agonist for B2 receptors?

A

Albuterol!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What do B2 receptors effect?

A

Less pronounced cardiac effects that B1

Relax respiratory, uterine, GI smooth muscle

Relax blood vessels supplying skeletal muscle

Promote potassium uptake into skeletal muscle

Increase glycogenolysis and gluconeogenesis in liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

B3 receptors have ONE FUCKING JOB. What the fuck is it?

A

Increase lypolysis in fat cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Dopamine receptors are of particular importance in ______ and _______

A

The brain and renal and splanchnic vasculature

D1: usually stimulates adenylyl cyclase —> dilation of renal blood vessels

D2: inhibit adenylyl cyclase —> open K+ channels and decrease Ca2+ influx —> inhibits release of NTs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Alpha receptor stimulation in the CV system:

A

Increases arterial resistance —> increase BP

The increased BP stimulates baroreceptors, which then increase vagal input to slow the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

In people with _______ the baroreceptors may be impaired and the effects of the alpha agonist on BP may be magnified

A

Atherosclerosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Effects of alpha agonists on the eye

A

Mydriasis (b/c radial muscle contraction)

Also increase the removal of aqueous humor, decreasing intraocular pressure - hence their use in glaucoma!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Effects of alpha agonists on the Respiratory tract

A

Blood vessels in the upper airway and mucous membranes contain alpha receptors —> vasoconstriction by decongestants serves to decrease nasal stuffiness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Effects of alpha agonists on GU tract

A

Constrict the bladder, sphincter and prostate, and promote continence

Also necessary for ejaculation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Effects of beta agonists on the CV system:

A

Increase rate, contractility and increased conduction velocity (positive chronotropic, inotropic, and dromotropic effect) - may be counteracted to some extent by reflex responses (baroreceptors)

O2 demand and consumption increased

Coronary blood flow also increased

B2 relax smooth muscles in blood vessels to skeletal muscle

Although CO increased, dilation of blood vessels results in decreased diastolic blood pressure (systolic may increase slightly)

26
Q

Effects of beta agonists on the eyes

A

Increase production of aqueous humor —> increased intraocular pressure

27
Q

Effects of beta agonists on respiratory tract

A

B2 agonists relax bronchial smooth muscle and widely used to treat asthma

28
Q

Effects of beta agonists on GU tract

A

Relaxation of the uterus by B2 receptors useful for treating premature contractions

B2 have small degree of relaxation of the urinary bladder wall

B3 relax the detrusor smooth muscle during the storage phase of the urinary bladder

29
Q

Metabolic/endocrine effects of beta agonists

A

Renin secretion increased (B1)

B2 promote glycogenolysis and uptake of potassium and insulin secretion

B3 stimulate lipolysis in fat cells

30
Q

Norepinephrine (Levophed) stimulates ____ and ____ receptors with little effect on ____ receptors

A

Alpha and B1, little effect on B2

Must be injected, very short duration due to rapid metabolism

Primary effect is on BP, with slight reflexive bradycardia

31
Q

If atropine is given prior to NE, the _______ is inhibited

A

Vagal reflex

The baroreceptors effect will not occur, so HR will increase

32
Q

NE can cause severe _________ at the infusion site

A

Vasoconstriction —> necrosis

33
Q

Epinephrine (Adrenalin) which receptors?

A

Alpha, B1 and B2 —> complex effect

Must be injected SC or IV and has a short duration of action due to rapid metabolism

Effect depends on the dose administered

34
Q

Dose dependence in Epi administration

A

If a low dose is infused slowly, b1 receptors will increase HR and conduction, coronary blood flow will increase and CO and O2 consumption increased; alpha receptors will constrict vessels —> increased BP and increased pulse pressure

If a rapid infusion of high dose epi, BP will increase substantially but with less increase in HR

35
Q

Epi is used for the treatment of ____________ to restore BP, decrease bronchospasm, decrease congestion and angioedema, and reverse CV collapse

A

Anaphylactic shock

Used in emergency treatment for cardiac arrest and heart block as well

36
Q

Vasoconstrictor property of epi is used to …

A

Decrease diffusion of injected drugs such as local anesthetic

37
Q

Epi can be distilled in the eye in glaucoma to …

A

Increase removal and decrease production of aqueous humor

38
Q

Epi toxicities

A

Tremor, throbbing headache, increased BP, and tachycardia, +/- angina

39
Q

When is epi injection contraindicated?

A

People taking beta-blockers, since unopposed effects on alpha receptors may lead to severe hypertension

40
Q

How is ephedrine different from epi?

A

Similar to epi but less pronounced

High bioavailability and long duration (may last hours)

Excreted in urine

CNS stimulant, increases HR and may increase BP

Causes bronchodilation

41
Q

Phenylpropanolamine, a component of many OTC decongestants and weight loss drugs was taken off the market because…

A

Hemorrhagic stroke in women

42
Q

Phenylephrine (neofrin) is a _____ selective agonist

A

Alpha 1

Causes vasoconstriction and increases peripheral vascular resistance —> increase in BP with reflexive decrease in HR

May be used in hypotensive emergency to raise BP

Also effective as a decongestant (but rebound effect)

People with HTN should use caution

Produces mydriasis

43
Q

Phenylephrine does what to the eyes?

A

Produces mydriasis and may be used topically to dilate the eye for exam without affecting accommodation

44
Q

How is pseudoephedrine different from phenylephrine

A

Also an alpha agonist and widely used OTC decongestant

More effective orally than phenylephrine but people use it to make meth, so there’s that.

45
Q

Direct acting alpha agonist which causes vasoconstriction and can be used on nasal mucosa and in the eye

A

Oxymetazoline (Afrin) - used as nasal spray to decrease congestion

Rebound effect occurs with chronic use (down-regulation)

Acts on alpha2 and could cause hypotension if large quantity absorbed systemically

The eye versions (tetrahydrozoline - Visine, and naphazoline - Privine) are all contraindicated in narrow-angle glaucoma and hypertension patients

46
Q

Oral prodrug in the same family as afrin and visine, used to treat symptomatic orthostatic hypotension

A

Mid o drink

47
Q

_______ is a selective a2 agonist that acts in the brain to decrease the release of NE and other NTs, reducing overall sympathetic output to the periphery

A

Clonidine (Catapres)

Reduced sympathetic tone —> decreased BP

Administered orally or by transdermal patch for the treatment of hypertension

Appears to reduce craving in recovering opioid addicts and alcoholics and decreases withdrawal Sx

Patch can help decrease hot flashes in menopause

May be used as a pre-anesthetic med

Side effects: dry mouth, sedation, ED in men

48
Q

What will happen if clonidine is withdrawn too abruptly?

A

Hypertension

49
Q

Other alpha 2 agonists besides clonidine?

A

Methyldopa

Apraclonidine used in eye to reduce pressure

Dexmedetomidine

Tizanidine has less effect on BP but is good at reducing muscle spasticity

50
Q

___________ is a very potent select B1 and B2 agonist that increases the rate and force of contraction of the heart, with vasodilation in skeletal muscle as well as in renal and mesenteric vascular beds.

A

Isoproterenol (Isuprel)

Systolic pressure may rise initially due to increased CO but dilation of skeletal blood vessels will lead to a decrease in BP with a reflex increase in HR

Used in EM tx for cardiac arrest and complete heart block

Large doses —> tachycardia, palpitations, and arrhythmias

51
Q

Dobutamine is a _____ agonist with some effect on alpha receptors

A

B1

Prominent positive inotropic effect in the heart

Increases CO and cardiac contractility

Frequently used in cardiac stress tests if patient cannot exercise

Half-life is only 2 min so effect is short

52
Q

Terbutaline, albuterol (ventolin) are selective _______

A

B2 agonists with little effect on B1 receptors in normal doses

Widely used for asthma

H/a, tachycardia, and skeletal muscle tremor common side effects

53
Q

Example of a beta-3 agonist

A

Mirabegron

Used for patients with overactive bladder

Side effects: nausea, headache, HTN, diarrhea, constipation, dizziness, and sinus tachycardia

54
Q

Low doses of __________ activate receptors in renal vascular beds —> vasodilation and increasing renal blood flow, GFR, and sodium secretion

A

Dopamine (via D1 receptor)

At high concentrations, stimulates B1 receptors in the heart, producing positive inotropic and chronotropic effect (good for cardiac shock b/c increases CO without vasoconstriction)

55
Q

What is Fenoldopam (Corlopam)?

A

Select D1 receptor agonist
Causes dilation of vascular beds, decreasing BP

Mainly used for rapid decrease in BP in severe HTN

56
Q

Amphetamine, Cocaine, and Tyramine are all examples of …

A

Indirect acting sympathomimetics

57
Q

Amphetamine works by …

A

Increasing release of NE (and DA) esp in the CNS

Used as a CNS stimulant

Side effects: tremor, tachycardia, and HTN, possibly psychosis

Can cause cerebral hemorrhage, convulsions, and coma at high doses

Can treat enuresis because it causes strong contraction of the urinary bladder sphincter

58
Q

Other drugs similar to amphetamine

A

Methamphetamine - more central actions and fewer peripheral effects; major drug of abuse

Methylphenidate (Ritalin) - used in ADHD where they cause a paradoxical decrease in hyperactivity

Amphetamine like compounds have been used for weigh loss but long term effect is minimal

59
Q

How does cocaine work again?

A

Inhibits re-uptake of DA and NE into nerve terminals

Shorter acting and more intense than amphetamine

May cause severe HTN and stroke

60
Q

How does Tyramine work?

A

Indirectly acting compound that will increase release of catecholamines from nerve terminals —> displace NE in storage vesicles

Normally, hydrolyzed by MAO

61
Q

In patients treated for depression with MAO inhibitors, ingestion of __________ may cause a severe ____________

A

Large amounts of tyramine —> severe hypertensive crisis

Pharm II Unit I (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions