Brainscape's Knowledge GenomeTM

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


See full index

Pharm II Unit I > 4 Adrenergic Blocking Agents > Flashcards

4 Adrenergic Blocking Agents Flashcards

1
Q

What do we mean when we say that the effect of an adrenergic blockade depends on the prevailing tone?

A

An antagonist won’t have an effect unless there is an agonist present (b/c there has to be something to block)

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

Things that help predict the effect of adrenergic antagonists?

A

Effect of blockade will depend on selectivity for alpha and beta receptors

Will depend on degree to which a particular tissue is innervated by alpha and beta

If alpha blocked, beta will dominate

If beta blocked, alpha will dominate

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

Are most alpha antagonists reversible or irreversible?

A 
Reversible!
• Phentolamine
•Prazosin, terazosin, doxazosin
• Tamsulosin
• Labetalol, carvedilol

The only irreversible one? Phenyoxybenzamine

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

For the most part, an alpha blockade will cause …

A

Decreased vasoconstriction in arteries and veins, lowering peripheral vascular resistance, especially when standing

Reflex tachycardia common (decreased BP —> baroreflex —> decreased vagal input)

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

_____________ is common with an alpha blockade because alpha1 receptors in veins are antagonized —> low pressure

A

Postural hypotension

Compensatory vasoconstriction upon standing is blocked

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

Epinephrine reversal of an alpha blockade

A

Blocking alpha receptors exposes effect of beta stimulation —> dilation of blood vessels in skeletal muscle causes drop in BP and heart rate increases

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

Other alpha block effects

A

Miosis (radial muscles relax)

Nasal stuffiness (vasodilation in nasal mucosa)

Decreased resistance to urine flow (widely used for the treatment of BPH)

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

Phentolamine is a competitive _____________

A

A1 and a2 antagonist

Decreases peripheral resistance and BP, esp diastolic

Tachycardia likely (b/c baroreceptors reflex)

Other side effects: arrhythmia, myocardial ischemia, hypotension

Used rarely due to poor pharmacokinetics

IS used in HTN crises due to pheochromocytoma or MAO inhibitors, or to prevent necrosis after local infusion of alpha agonist (ie infiltrated pic lines)

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

Treatment for pheochromocytoma

A

Pheos get phenos

Either Phenoxybenzamine (or Phentolamine - but poor pharmacokinetics)

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

Phenoxybenzamine is a very long acting, irreversible _________

A

Non-specific alpha blocker

Tachycardia likely

Sympathetic tone determines effect

Used in PHEOCHROMOCYTOMA

Side effects: postural hypotension, tachycardia, nasal congestion, inhibition of ejaculation, hypotension

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

Prazosin (minidress) is a ___________ blocker

A

A1 selective

Lack of a2 block means less reflex tachycardia

Beneficial effects on lipids

Must be given twice daily (terazosin/doxazosin have better pharmacokinetics and can be taken 1/day)

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

First dose phenomenon with Prazosin

A

Postural hypotension and syncope 30-90 min after 1st dose

Have patient take 1st dose at bedtime, so lying down for some hours

May also happen when dose increased or second drug added

Can also have orthostatic hypotension (don’t get out of bed too quickly), dizziness, nasal stuffiness

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

If you have a dude with HTN and BPH, what should you give him?

A

Prazosin! Or another zosin

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

A good option for men who have had postural hypotension with other alpha blockers?

A

Tamsulosin

A1a selective (important for prostate) while A1b is the blood vessels - so Tamsulosin has little effect on BP

Main side effect is difficulty ejaculating

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

What herbal supplement that men with limp dicks try is likely to interfere with the effect of clonidine?

A

Yohimbine

Blocks alpha2, increases NE release, increases BP and HR

Can be dangerous in men with untreated or uncontrolled HTN

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

Beta blockade work by

A

Decreasing HR and contractability —> decreased o2 demand and CO and decreased renin release from kidney

Lowers BP when used chronically, greatest effect when sympathetic tone high

17
Q

Short term use of beta blocker for BP reduces CO but…

A

Long term administration actually decreases BP as peripheral resistance returns to pre-drug value

18
Q

Beta blockers can be fatal in patients with …

A

Severe asthma/COPD (though a B1 selective drug may be tolerated)

19
Q

Effect of beta blockade on the eyes

A

Lowers intraocular pressure by decreasing formation of aqueous humor

Topical use in glaucoma

20
Q

How do beta blockers affect the liver?

A

Inhibits glycogenolysis - masks symptoms of hypoglycemia in insulin-dependent diabetics and makes it harder to recover from hypoglycemia (b1 selective antagonists have less effect on glucose)

Inhibits lipolysis in fat cells

Increases VLDL and decreases HDL

K+ uptake into muscle blocked

21
Q

Beta blockers can have “membrane stabilizing” effect, meaning,

A

Sodium channel blockade (true of several of them)

Some are used as anti-arrhythmic agents

22
Q

Propranolol is a competitive antagonist of ___________

A

B1 and B2 receptors

Decreases HR, contractility, renin, lipolysis, glycogenolysis

Can also be used as a local anesthetic

Oral, low bioavailability so dose varies, can enter CNS (sedation likely)

23
Q

Why isn’t propranolol a first line treatment for HTN anymore?

A

Decreases BP with chronic use - better drugs now

But it DOES decrease mortality following MI and improves symptoms of angina (because decreases O2 demand)

Can also be used as an antiarrhythmic in obstructive CM and early CHF

24
Q

Other weird things about propranolol

A

Decreases HR in hyperthyroidism
Prevents migraines
Decreases portal vein pressure, reduced bleeding in cirrhosis
Used to decrease sympathetic symptoms of stage fright
Used in familial tremor

Weird, huh?

25
Q

Major side effect of propranolol

A

BRONCHOCONSTRICTION - don’t use in asthmatics or COPD patients

Can also exacerbate late CHF

Sedation, fatigue, depression common

Caution in insulin-dependent DM

Lipids

26
Q

Abrupt d/c of propranolol can cause …

A

Arrhythmia

27
Q

___________ have an additive effect with propranolol in terms of AV block

A

Calcium channel blockers

28
Q

Timolol is a non-selective B blocker used in…

A

The eye tor treat glaucoma

Caution in asthmatics! May be absorbed systemically and that’s bad

29
Q

Nadolol is …

A

Long acting, doesn’t get into the CNS

30
Q

Sotalol is an

A

Antiarrhythmic

31
Q

Meds that cause a B1 selective blockade?

A

Metoprolol, Atenolol, Bisoprolol

Effects primarily on the heart (decreased HR, contractility, o2 demand) but also decreases renin

Overall, will decrease BP, used for treatment of HTN

Increased life expectancy with use after MI

Can also be used for migraine prophylaxis

Better exercise tolerance and safer in DM

32
Q

Nebivolol (Bystolic)

A

Highly B1 selective

Produces vasodilation due to NO release

Better effect on BP, fewer side effects

Less effect on lipids, glucose than other beta blockers

33
Q

Esmolol (Brevibloc)

A

VERY short acting beta1 blocker - rapidly degraded by esterases in RBCs

Given IV when you want a short effect - onset rapid and terminates quickly

Infusion may be continued as long as necessary

34
Q

Med used in CHF/post MI that blocks both B and A receptors

A

Carvedilol

It’s sister drug Labetalol used IV for HTN emergency but can cause hepatic problems

Pharm II Unit I (4 decks)

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