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Flashcards in Mod 5 Adrenergic blockers Deck (17):
1

Adrenergic Blockers

 Bind to adrenergic receptors, but inhibit or block stimulation of the sympathetic nervous system (SNS)
 (alpha) (alpha)--blockers and (beta)beta--blocker

2

Adrenergic Blockers (cont’d)

 Have the opposite effect of adrenergic drugs
 Inhibit—or lyse—sympathetic stimulation
 Also known as:
 Adrenergic antagonists
 Sympatholytics
 Alpha-blockers, beta-blockers, or alpha-beta blockers

3

Adrenergic Blockers (cont’d)

Classified by the type of adrenergic receptor they block
1 and 2
receptors

4

Drug Effects and Indications:
Alpha-Blockers

Cause both arterial and venous dilation,
reducing peripheral vascular resistance and
BP
 Used to treat hypertension
 Effect on receptors on prostate gland and
bladder decreases resistance to urinary
outflow, thus reducing urinary obstruction and relieving effects of BPH

5

Drug Effects and Indications:
Alpha-Blockers (cont’d)

 Used to control and prevent hypertension in patients with pheochromocytoma
 Phentolamine
 Quickly reverses the potent vasoconstrictive effects of extravasated vasopressors such as
norepinephrine or epinephrine
 Restores blood flow and prevents tissue necrosis

6

--Blockers: Adverse Effects Blockers: Adverse Effects

Body System Adverse Effects
Cardiovascular Palpitations, orthostatic Palpitations, orthostatic
hypotension, tachycardia, edema, dysrhythmias, chest pain
CNS Dizziness, headache, drowsiness,
anxiety, depression, vertigo,
weakness, numbness, fatigue

7

--Blockers: Adverse Effects (cont’d) Blockers: Adverse Effects (cont’d)

Body System Adverse Effects
Gastrointestinal Nausea, vomiting, diarrhea,
constipation, abdominal pain
Other Incontinence, nosebleed
tinnitus, dry mouth, pharyngitis,,
rhinitis

8

Common --Blockers Blockers

 phenoxybenzamine HCl (Dibenzyline)
 phentolamine (Regitine)
 prazosin (Minipress)
 tolazoline (Priscoline)

9

--Blockers

 Block stimulation of  receptors in
the SNS
 Compete with Compete with norepinephrine and epinephrine
 Selective and nonselective --blockers
 Nonselective --blockers block both
1 and 2 receptors

10

 Receptors

 Beta1 receptors
 Located primarily on the heart
 Beta-blockers selective for these receptors
are called cardioselective beta-blockers
 Beta2 receptors
 Located primarily on smooth muscle of
bronchioles, blood vessels and uterus

11

Mechanism of Action

 Cardioselective beta-blockers (beta1)
 Reduce SNS stimulation of the heart
 Decrease heart rate
 Prolong SA node recovery
 Slow conduction rate through the AV node
 Decrease myocardial contractility, thus reducing myocardial oxygen demand

12

Mechanism of Action

 Nonselective beta-blockers (beta1
and beta2)
 Cause same effects on heart as cardioselective beta-blockers
 Constrict bronchioles, resulting in narrowing of airways and shortness of breath
 Produce vasoconstriction of blood vessels

13

Indications

 Angina
 Decreases demand for myocardial oxygen
 Cardioprotective
 Inhibits stimulation from circulating
catecholamines
 Dysrhythmias
 Class II antidysrhythmic
 Migraine headache
 Lipophilicity allows entry into CNS

14

Indications

Antihypertensive
Heart failure
Glaucoma (topical use)

15

Adverse Effects: --Blockers

Body System Adverse Effects
Blood Agranulocytosis, thrombocytopenia
Cardiovascular AV block, bradycardia,
heart failure peripheral vascular
insufficiency
CNS Dizziness, mental depression,
lethargy, hallucinations

16

Adverse Effects:
Adrenergic--Blocking Drugs

--blockers blockers
Body System Adverse Effects
Gastrointestinal Nauseaausea,, dry mouth vomiting,,
diarrhea, cramps, ischemic colitis
Other
Impotence, rash, alopecia, Impotence, rash,
bronchospasm

17

--Blockers: Examples

 acebutolol (Sectral Sectral)
 carvedilol (Coreg)
atenolol (Tenormin Tenormin)
 esmolol (Brevibloc)
 carvedilol (Coreg)
labetalol (Trandate Trandate)
metoprolol (Lopressor)
 esmolol (Brevibloc)
sotalol (Betapace Betapace)
propranolol (Inderal Inderal)