CV Stimulants

Question 1

Alpha receptors in blood vessels affect

Answer 1

contraction on the vessels

Question 2

Affects of epinephrine

Answer 2

locally increase BP through alpha receptors; increase HR and CO through Beta

Question 3

Affects of norepinephrine

Answer 3

increased BP through alpha receptors

Question 4

Affects of dopamine

Answer 4

at high doses increase BP (alpha) and increase HR and CO (beta)

Question 5

Affects of isoproterenol

Answer 5

increase HR and CO (beta)

Question 6

Affects of Phenylephrine

Answer 6

increase BP (alpha)

Question 7

Affects of ephedrine

Answer 7

at high doses increase BP (alpha) and increase HR and CO (beta)

Question 8

Activation of Alpha 1

Answer 8

formation of IP3 and DAG, increased intracellular calcium

Question 9

Activation of Alpha 2:

Answer 9

inhibition of adenylyl cyclase, decreased cAMP

Question 10

Activation of Beta 1:

Answer 10

stimulation of adenylyl cyclase, increased cAMP

Question 11

Activation of Beta 2:

Answer 11

stimulation of adenylyl cyclase and increased cAMP

Activates cardiac Gi under some conditions

Question 12

Activation of Beta 3:

Answer 12

stimulation of adenylyl cyclase and increased cAMP

Question 13

Activation of D1 and D5

Answer 13

stimulation of adenylyl cyclase and increased cAMP

Question 14

Activation of D2

Answer 14

decreased adenylyl cyclase; increase K+ conductance

Question 15

Direct acting drugs MOA

Answer 15

stimulate postsynaptic receptors

Question 16

Indirect acting drugs MOA:

Answer 16

increase availability of NE or E by releasing or displacing NE from sympathetic nerves, blocking transport of NE into sympathetic neurons, block metabolizing enzymes

Question 17

Mixed-acting drugs

Answer 17

direct activation of postsynaptic receptors and indirect release of NE

Question 18

Reserpine’s effect on effectiveness of direct, indirected, and mixed-acting drugs

Answer 18

Direct: response are not reduced

Indirect: responses are abolished

Mixed: responses are blunted, but not abolished

Question 19

Differences in CV effects by E and NE

Answer 19

E: increases HR, CO, unpredictable effect on diastolic arterial pressure with large increase in systolic, decreased peripheral resistance

NE decreases HR and has no effect or decreases CO, increases Diastolic arterial pressure and large increase in systolic, increased peripheral resistance

Question 20

Epinephrine effect on the heart

Answer 20

increased HR, shortened systole, increased CO, increased Oxygen consumption

Can cause premature ventricular contractions, leading to extrasystoles, tachycardia, or fibrillation

Question 21

Epinephrine vascular effects

Answer 21

decreased cutaneous BF, increased B2 mediated skeletal BF, increased renal resistance with decreased BF, increased pulmonary pressures, and increased coronary BF

Question 22

Epinephrine absorption

Answer 22

IV, Inhaled, IM, SC (slow due to vasoconstriction)

Cannot give orally due to high metabolic rate

Question 23

Epinephrine toxicity

Answer 23

Cerebral hemorrhage especially with non-specific beta blockers, ventricular arrhythmias, and angina

Question 24

Uses of epinephrine

Answer 24

emergency relief of hypersensitivity reactions, vasoconstrictor with local anesthetics, topical hemostatic agent, restoring cardiac rhythm in patients with cardiac arrest

Question 25

Toxicity of norepinephrine

Answer 25

cerebral hemorrhage, ventricular arrhythmias, angina, extreme increases in BP, necrosis at sites of IV infusion

Question 26

Dopamine

Answer 26

Concentration dependent receptor specificity from low to high dose (D1 -> B1 -> A)

Used acutely in CHD or RF

Given IV infusion; has short duration of action

Must monitor urine output as secondary marker of drug effect - may have bad effects on kidneys, where it is metabolized

Question 27

Dobutamine

Answer 27

Racemic mixture of a beta agonsit and alpha1 agonist and antagonist

Increases CO and SV without effect on HR through increased myocardial contractility with decreased LV filling pressure; increased urinary output secondary to increased CO

Very short half life (2min), IV

For short term treatment of cardiac decompensation post surgery, CHF, or acute MI

Question 28

Isoproterenol

Answer 28

Acts on beta receptors; increases CO, decreases diastolic BP

Given parenteral or by aerosol

SE: palpitations, tachy, headache, flushing

Uses: Emergency to stimulate HR in pts with brady or heart block - especially patients with torsades or about to receive implanted pacemaker

Question 29

Phenylephrine

Answer 29

Direct acting alpha adrenergic agonsit; causses systemic vasoconstriction, thus increased SBP&DBP

Can cause reflex decreased HR and CO

SC, IM, IV

use of control of hypotension (also associated with regional/spinal anesthesia

SE: angine, anxiety, hallucinations, HTN, excitability, dizziness, insomnia, pallor, restlessness - all more likely with parenteral administration

Question 30

Ephedrine

Answer 30

Mixed acting sympathomimetic agonist at both alpha and beta receptors and enhances release of NE from sympathetic neurons

Orally active, eliminated unchanged in urine

Uses: hyptonesion and hypotension of analgesia

increased HR and CO, variable increased in peripheral resistance and BP

SE: angina, ventricular dysfunction including arrhythmias and palpitations, fatal arrhythmias including V tach