Sympatholytics: The alpha and beta receptor antagonist Flashcards

Question

How does phenoxybenzamine impact the heart?

Answer 1

Rate and cardiac output is increased due to reflex tachycardia and increased NE release produced by the blockade of pre-synaptic a2-receptors and by the blockade of NE transporters leading to increased b1-receptor stimulation.

Answer 2

effects of phenoxybenzamine on other organ systems are the | same as phentolamine but they last longer

Answer 3

``` Orthostatic hypotension Fainting Tachycardia Stuffy nose Miosis Inhibition of ejaculation Fatigue and sedation ```

Answer 4

Same as phentolamine

Answer 5

Coronary artery disease CHF Respiratory infection (aggravates stuffy nose).

Answer 6

its an alpha one antagonist

Answer 7

Useful in the treatment of hypertension usually as a second alternative, a second add-on or as a third add-on. Also used for CHF and pheochromocytoma.

Answer 8

Given orally and is readily absorbed. Highly protein bound. Durationof action is -10 hrs. Can enter the CNS

Answer 9

Selective competitive a1-receptor antagonist;

Answer 10

blockade of post-synaptic a1-receptors on the smooth muscle of both veins and arteries, producing vasodilation. Causes a decrease in peripheral resistance and decreases venous return to the heart.

Answer 11

Tachycardia is absent likely due to a lack of a2-receptor blockade and a depression of sympathetic outflow in the CNS. The decrease in peripheral resistance decreases cardiac preload (filling pressure) thus having little effect on cardiac output and rate.

Answer 12

Vasodilation produces a decrease in pre-load (filling pressure) and afterload (resistance against which the heart pumps) which increases cardiac output and decreases pulmonary congestion.

Answer 13

reduces the tone of the trigone and sphincter to | decrease the resistance to urinary outflow. May be useful in patients with impaired emptying

Answer 14

First dose can result in orthostatic hypotension - 0.5-2 hrs after initial dose. More likely to occur in geriatric patients and those who are volume depleted. Begin with an initial 1 mg dose increase gradually. Angina Fainting due to orthostatic hypotension Irregular heartbeat Tolerance to the CHF effects after long-term use.

Answer 15

may block the anti-hypertensive effect by inhibition of renal prostaglandin synthesis, thus causing Na+ and fluid retention.

Answer 16

potentiated effects

Answer 17

mutual inhibition of effects

Answer 18

A selective antagonist of alpha1A (a1A) adrenoceptors in prostrate.

Answer 19

treatment of benign prostatic hyperplasia (BPH).

Answer 20

use by men only

Answer 21

Highly selective for alpha 1 receptors in the human prostate. Relaxes the muscles in the prostate and bladder neck at the site of obstruction, resulting in improved urine flow and reduced BPH symptoms. Not used as an antihypertensive

Answer 22

Fainting due to orthostatic hypotension | Priapism (very rarely)

Answer 23

Other hypotension producers- Potentiate effects

Answer 24

sympatholytics

Answer 25

Actidine, Aphrodyse, Yocan,

Answer 26

Used for the treatment of erectile impotence- herbal viagra. Improve symptoms in patients with painful diabetic neuropathy or Raynaud’s syndrome.(abnormal vasoconstriction of the extremities upon exposure to cold or emotional distress).

Answer 27

Rapidly absorbed. The onset of action is 2-3 weeks. Enters the CNS

Answer 28

Selective, competitive a2-receptor antagonist

Answer 29

Increase in blood pressure and heart rate. Dizziness, headache and nervousness. Nausea or vomiting (rare)

Answer 30

- Antidepressants and mood modifiers- antagonize their effects. - Anti-hypertensives- may block their effect.

Answer 31

- Angina - Cardiac disease - Hypertension - Renal impairment

Answer 32

due to their efficacy in treating hypertension, ischemic heart disease, congestive heart failure and certain arrhythmias.

Answer 33

The pharmacological properties can be largely explained based on the responses elicited by the receptors in the various tissues and the activity of the sympathetic nerves that innervate these tissues. For eg. b-receptor blockade has relatively little effect on the normal heart of an individual at rest but has profound effects when sympathetic control of the heart is dominant as during exercise or stress. The major therapeutic effects are on the cardiovascular system in individuals.

Answer 34

sympatholytic-beta blocker

Answer 35

Used for treatment of chronic angina, cardiac arrhythmia,hypertension as a first line agent, cardiomyopathy, myocardial re-infarction (prophylaxis), pheochromocytoma (adjunct), vascular headache, tremors, physical symptoms of anxiety, mitral valve prolapse and thyrotoxicosis.

Answer 36

Non-selective b-blocker- prototypical agent

Answer 37

Given orally or as an IV solution. When administered orally, multiple, increasing does may be required.

Answer 38

well absorbed and highly lipophilic it enters the CN

Answer 39

- Blocks the action of NE and EPI at the b1-receptors on the heart. At rest there is little sympathetic activity thus, the effect on heart rate and force of contraction is small. When the sympathetic system is activated, the effect of b-blockers is more pronounced and the increase in heart rate and contractility is reduced.

Answer 40

short term b-blocker use decreases cardiac output resulting in reflex vascular constriction via a1-receptor activation and blockade of b2-receptors in the vasculature of the skeletal muscles. The result is an increase in total peripheral resistance. After long-term use the total peripheral resistance decreases but the reason is unclear.

Answer 41

Improves the relationship between O2 supply and | demand.

Answer 42

Reduction in sinus rate, a decrease in the spontaneous rate of depolarization of the pacemaker cells, a slowing of the conduction in the atria and the AV node and an increase in the refractory period of the AV node.

Answer 43

Does not reduce blood pressure in patients | with normal B.P. B.P. lowering mechanism(s) are not well understood.

Answer 44

Blocks the b2-receptors on the smooth muscle of the lung. In normal individuals it is of little consequence. In someone with chronic pulmonary obstructive disease it can lead to dangerous bronchoconstriction.

Answer 45

Modifies the metabolism of glycogen and | glucose (carbohydrates). May slow the recovery from hypoglycemia. No real effect on insulin release.

Answer 46

Although propranolol is not used ophthalamically, other nonselective b-blockers are (i.e. timolol). Blockade of b-receptors in the ciliary body (not muscle) reduces the production of aqueous humor thereby reducing fluid input and thus the pressure. Many of these compounds can enter the systemic circulation.

Answer 47

characterized by elevated catecholamines, which may adversely affect the cardiovascular system. The b-blockers antagonize the effects of the elevated catecholamine levels on the heart. .

Answer 48

``` Mental depression - due to CNS effects. Wheezing - greater risk in obstructive pulmonary disease. Slow heartbeat Decreased sexual ability Diarrhea Dizziness Drowsiness Nausea and vomiting Numbness and tingling Trouble sleeping ```

Answer 49

Abrupt discontinuation of b-blockers is very dangerous possibly due to upregulation of the b-receptors.

Answer 50

``` Fast or irregular heartbeat- dangerous in those with heart disease. Chest Pain Headache Shortness of Breath Sweating Trembling ```

Answer 51

increased risk of hypoglycemia

Answer 52

potentiated hypotensive effects. Never discontinue two agents at once, may lead to hypertensive crisis

Answer 53

Mutual inhibition of effects. Unopposed a | receptor stimulation results in hypertension and bradycardia.

Answer 54

(theophylline)- mutual inhibition of pulmonary effects

Answer 55

cardiac failure, heart block and sinus bradycardia

Answer 56

Allergy, asthma and emphysema Diabetes Hyperthyroidism - may mask symptoms Mental depression

Answer 57

It is b2-receptor selective but has no therapeutic value. You should be able to figure out why

Answer 58

Antagonizes both b1 and b2 receptors and it is devoid of membrane stabilizing and intrinsic sympathomimetic activity. Distinguishing character is its relatively long half-life.

Answer 59

Non-selective b adrenergic antagonist with no membrane stabilizing activity. Used for the treatment of glaucoma. When given in the eye may be absorbed systemically.

Answer 60

Blocardren

Answer 61

Non-subtype selective b adrenergic antagonist with intrinsic sympathomimetic activity. May produce smaller reductions in resting heart rate and blood pressure. Preferred antihypertensive in individuals with diminished cardiac reserves or a propensity for bradycardia.

Answer 62

Lopressor, Toprol

Answer 63

for the treatment of angina, hypertension (initial therapy), arrhythmia, cardiomyopathy, prophylaxis for myocardial reinfarction, pheochromocytoma, vascular headache, tremors and anxiety.

Answer 64

Can be given orally or IV

Answer 65

selective antagonist of b1-receptors

Answer 66

At higher doses increased increased b2-blockade occurs. Since there is little b2-receptor blockade, theoretically the risk of bronchospasm, hyperglycemia and peripheral vasoconstriction (at the skeletal muscle) is reduced.

Answer 67

The side effects, drug interactions and contraindications are the same as propranolol.

Answer 68

b1 Selective

Answer 69

Devoid of intrinsic sympathomimetic activity

Answer 70

Highly hydrophilic and will penetrate the brain to a limited extent

Answer 71

Very short duration of action with a half life of about 10 minutes

Answer 72

Used when b blockade of short duration is needed in critically ill patients in whom adverse effects of bradycardia, heart failure, or hypotension may necessitate rapid withdrawal of the drug.

Answer 73

In addition to b1 blockade agent possesses some intrinsic sympathomimetic activity.

Answer 74

Used for the treatment of hypertension and ventricular arrhythmias