Adrenoceptor Antagonists Flashcards Preview

Pharmacology- Katzung (Spring 2019) > Adrenoceptor Antagonists > Flashcards

Flashcards in Adrenoceptor Antagonists Deck (40)
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1
Q

Peripheral vascular resistance - Effects of alpha1 and beta 1 blockers

A

alpha1 blockers: reduced peripheral vascular resistance

beta1 blockers: slight increase in peripheral vascular resistance as a results of reflex vasoconstriction

2
Q

Cardiac output - Effects of alpha1 and beta 1 blockers

A

alpha1 blockers: increase CO by decreasing cardiac after load and aortic impedance to ventricular ejection of blood
beta1 blockers: reduce CO

3
Q

Mean arterial BP- Effects of alpha1 and beta 1 blockers

Kidneys - Effects of beta 1 blockers

A

Mean arterial BP: Both reduce

Kidneys: Reduces renin secretion –> reduces synthesis of angiotensin –> reduces NP

4
Q

Nonselective alpha blockers + noncompetitive/competitive

A

Phenoxybenzamine (noncompetitive)

Phentolamine (competitive)

5
Q

Phenoxybenzamine - MoA and Effect

A

Undergoes nonenzymatic chemical transformation to and active metabolite that forms a long-lasting covalent bond with alpha-adrenoceptors, resulting in noncompetetive receptor blockade.

Casues vasodilation –>Decreases vascular resistance and lowers both supine and standing BP.

6
Q

Phenoxybenzamine - Indication

A

Hypertensive episodes in pat with pheochromocytoma (used to control hypertension until surgery can be performed to remove tumor).

7
Q

Phentolamine - MoA

A

Competetive adrenoceptor antagonist, produces vasodilation, decreases peripheral vascular resistance and decreases BP.

8
Q

Phentolamine - Indication

A

Acute hypertensive episodes caused by adrenoreceptor agonists

Counteract local ischemia caused by accidental injection or extravasation (leakage from IV infusion) of epinephrine or other vasopressor amines.

9
Q

Why is nonselective alpha adrenoceptor antagonists not useful in treating chronic hypertension?

A

Evoke reflex tachycardia and may cause dizziness, headache and nasal congestion.

10
Q

Nonselective alpha adrenoceptor antagonists -Adverse Effects

A

Reflex tachycardia
Dizziness
Headache
Nasal congestion

11
Q

Selective alpha adrenoceptor antagonists

A
Prazosin
Doxazosin
Terazosin
Alfuzosin
Silodosin
Tamsulosin
12
Q

Selective alpha adrenoceptor antagonists - MoA

A

Selectivley block alpha1 adrenoceptors and relax vascular and other smooth muscles, including those of urinary bladder, urethra and prostate. Produce vasodilation and decrease BP.
Competitive alpha 1 adrenoceptor antagonists

13
Q

Selective alpha adrenoceptor antagonists - Indication

A

Used to treat essential(primary) hypertension

Lower urinary tract symptoms associated with benign prostatic hyperplasia and other conditions.

14
Q

Selective alpha adrenoceptor antagonists - Adverse effects

A

Less reflex tachycardia then Phentolamine and other nonselective α1-and α2-adrenoreceptors

Hypotension
Dizziness
Sedation
Small percentage of men have abnormal ejaculation.

15
Q

Prazosin, Doxazosin and Terazosin - Indication

A

Hypertension; Urinary symptoms caused by benign prostatic hyperplasia

16
Q

Which selective alpha-adrenoceptor antagonists are not used for treating hypertension but only symptoms of urinary outflow obstruction in men with benign prostate hyperplasia?

A

Alfuzosin, Silodosin, Tamsulosin

17
Q

Which selective alpha-adrenoceptor antagonists have higher incidence of adverse effects?

A

Doxazosin and Terazosin

18
Q

Alfuzosin, Silodosin and Tamsulosin - MoA

A

Competetive alpha1 blocker.

Selectively block alpha1A-adrenoreceptors, which is the alpha1-receptor subtype that mediates contraction of the ureter and urinary bladder.

19
Q

Nonselective beta-adrenoceptor antagonists - MoA

A

Block beta1-adrenoreceptors in the heart and other tissues

Block beta2-adrenoreceptors in blood vessels, lungs, and the liver

Competitvely block the effect of norepinephrine and other adrenoceptor agonists at beta1 and beta2 adrenoceptors.

They all decrease cardiac rate, output, AV node conduction and O2 demand and blood pressure

20
Q

Nonselective beta-adrenoceptor antagonists - Adverse effects

A

Beta2-blockers in liver inhibit epinephrine stimulated glycogenolysis and can thereby reduce hepatic glucose output during hypoglycemia resulting from excessive insulin adm. –> tachycardia and sweating(early signs of hypoglycemia)

Beta2-blockers can cause adverse reaction in asthma patients, due to bronchoconstriction, these persons depend on endogenous epinephrine to prevent bronchospasm, so beta2-blockers should be used with caution.
–> rather beta1-blockers in these patients.

Decreased peripheral blood flow during exercise, and a risk of cold extremities

21
Q

Nonselective beta-adrenoceptor antagonists

A
Nadolol
Pindolol
Propranolol
Timolol
Carteolol
22
Q

Nadolol - MoA and Indication

A

beta1- and beta2-blocker

Hypertension
Angina pectoris
Migrane headache

23
Q

Pindolol - MoA and Indication

A

beta1- and beta2-blocker with ISA and MSA

Hypertension

24
Q

Propranolol - MoA an Indication

A

beta1- and beta2-blocker with MSA

Hypertension
Angina pectoris
Cardiac dysrhythmias 
Hypertrophic subaortic stenosis
Essential tremor
Migrane headache 
Acute thyrotoxicosis
Acute myocardial infaction
Pheochromocytoma
25
Q

Timolol - MoA and Indication

A

beta1- and beta2-blocker
Reduce intraocular pressure by decreased aqueous humor production

Glaucoma
Hypertension
Acute myocardial infarction
Migrane headace

26
Q

Carteolol - MoA and Indication

A

beta1- and beta2-blocker
Reduce intraocular pressure by decreased aqueous humor production

Glaucoma
Intraocular hypertension

27
Q

Carteolol - Adverse effects

A

Temporary blurred vision

Temporary burning/stinging/itching/redness of the eye may occur.

28
Q

Selective beta-Adrenoceptor antagonists

A
Acebutolol
Atenolol
Esmolol
Betaxolol
Bisoprolol
Metaprolol
Nebivolol
29
Q

Acetbutolol - MoA and Indication

A

beta1 blocker with ISA(intrinsic sympathomimetic activity, partial agonist activity) and MSA(membrane stabilizing activity, local anesthetic activity)

Hypertension; cardiac arrhythmias

30
Q

Atenolol - MoA and Indication

A

b1-blocker

Hypertension
Angina pectoris
Acute myocardial infarction

31
Q

Esmolol - MoA and Indication

A

b1-blocker

Hypertension and Supraventricular tachycardia when these occur during surgery and in other situations

32
Q

Betaxolol - MoA and Indication

A

b1-blocker, decreases intraocular pressure

Glaucoma

33
Q

Bisoprolol - MoA and Indication

A

b1-blocker

Hypertension

34
Q

Metoprolol - MoA and Indication

A

b1-blocker with MSA

Hypertension
Angina pectoris
Acute myocardial infarction

35
Q

Nebivolol - MoA and Indication

A

b1-blocker - Hypertension

36
Q

alpha- and beta-Adrenoceptor antagonists

A

Carvedilol

Labetalol

37
Q

Carvedilol - MoA and Effect

A

beta1- and beta2-blocker
alpha1-blocker

Decreases cardiac afterload, increases cardiac output in patients with heart failure.

Antioxidant effects:
Inhibition of lipid peroxidation in myocardial membranes
Scavenging of free radicals
Inhibition of neutrophil release of O2

Antiapoptotic properties that can prevent myocyte death and reduce infarct size in persons with myocardial ischemia. For these reasons, carvedilol has been called a “third-generation -blocker and neurohumoral antagonist”.

38
Q

Carvedilol - Indication

A

Hypertension

Heart failure

39
Q

Labetalol - MoA

A

beta1- and beta2-blocker with MSA
alpha1-blocker, but more potent as a beta-blocker.

Decreases heart rate and cardiac output as a result of blocking beta1-adrenoceptors

Decreases peripheral vascular resistance as a result of alpha1-receptor blockade

40
Q

Labetalol - Indication

A

Hypertension

Decks in Pharmacology- Katzung (Spring 2019) Class (52):