Drugs Affecting the Cardiovascular System I: Ionotropic Drugs

Question 1

what is the function of positive ionotropic drugs

Answer 1

□ Positive inotropic agents enhance cardiac

muscle contractility and cardiac output

Question 2

Inotropic action is result of increased cytoplasmic

_______concentration

Answer 2

Inotropic action is result of increased

cytoplasmic calcium concentration

Question 3

what are the 3 broad catergories of ionotrpic drugs

Answer 3

Digitalis glycosides
β-adrenergic agonists
Phosphodiesterase inhibitors

Question 4

Digitalis glycosides influence what ions in cardiac muscle

Answer 4

sodium and calcium

Question 5

why dont we use Digitalis glycosides

Answer 5

they have a low therapeutic index

Question 6

How does digoxin work

Answer 6

□ Digoxin inhibits Na+/K+-ATPase and increase intracellular Na+.

This causes an increase in Na in the cell,this produces a secondary increase in intracellular ca 2+, which increases the for force of heart contraction

Question 7

how does digoxin increase calcium levels

Answer 7

by blocking the na k atpase

Question 8

is digoxin a first line drug

Answer 8

no! only uses in Severe left ventricular systolic dysfunction after
initiation of ACE inhibitor and diuretic therapy

Question 9

if pts respond to direutics and ace inhibitors is digoxin used

Answer 9

no

Question 10

list some Adverse effects of digoxin

Answer 10

Arrhythmias can occur at concentrations 2-3x
that of optimal therapeutic concentrations

□ Decreased K+ increases cardiotoxicity

□ Digoxin levels must be closely monitored in
the presence of renal insufficiency or else you have higher amounts

Cardiac effects
 Atrial arrhythmia (slowing of AV conduction). A
decrease in intracellular K+ is the primary factor

□ Gastrointestinal effects
 Anorexia, nausea, vomiting

□ CNS effects
 Headache, fatigue, confusion, blurred vision,
alterations of color perception, halos on dark
objects

Question 11

what things can enhance digoxin toxicity

Answer 11

□ Electrolyte imbalance such as low k levels

Drugs: Quinidine, verapamil, and amiodarone

Question 12

what factors predispose someone to digoxin toxicity?

Answer 12

Hypothyroidism, hypoxia, renal failure and

myocarditis are predisposing factors to digoxin toxicity

Question 13

t/f taking other drugs can enhance the toxic effects of digoxin

Answer 13

true

Question 14

if someone has digoxin toxicity what can be done

Answer 14

1. Adjustment of dose or discontinue digoxin therapy
2. Use of K+-sparing diuretic or supplementation with
   KCl
3. Antiarrhythmic drugs (phenytoin, lidocaine)
4. Digoxin-specific antibody fragments (Fab)

Question 15

list 2 beta adrenergic agonisits

Answer 15

(dobutamine) and

inamrinone

Question 16

beta adrenergic agonists help to increase ___ within the cell

Answer 16

calcium

Question 17

what g protein is responsible for increasing Camp levels

Answer 17

GS

Question 18

The more calcium that is avialible in the cell, the more likely heart can ___

Answer 18

contract

Question 19

what is the funtion of phosphodiesterase inhibitors

Answer 19

they block the degradation of cyclic amp by blocking phosphodiesterase inhibitors