Drugs Modifying Cardiac Rate and Force

Question 1

Give examples of beta-adrenoreceptor agonists

Answer 1

Dobutamine
Adrenaline
Noradrenaline

Question 2

What effects do beta agonists have on the cardiovascular system?

Answer 2

Increased heart rate, heart force and cardiac output

May cause arrhythmias

Question 3

Give an example of a non-selective beta-adrenoceptor antagonist

Answer 3

Propranolol (blocks both B1 and B2 receptors)

Question 4

Give two examples of B1 selective antagonists

Answer 4

Atenolol

Bisoprolol

Question 5

What effects do beta blockers have on the cardiovascular system?

Answer 5

Decrease heart rate
Decrease force
Decrease AV node conduction velocity

Question 6

When are beta blockers used?

Answer 6

Arrhythmias (A Fib and SVT)
Angina
Heart failure
Hypertension

Question 7

Give an example of a non-selective muscarinic ACh receptor antagonist

Answer 7

Atropine

Question 8

What effect does atropine have?

Answer 8

Increases heart rate

Question 9

When is atropine used?

Answer 9

Bradycardia (particularly following MI)

Question 10

What type of drug is digoxin?

Answer 10

Cardiac glycoside

Question 11

When is digoxin used?

Answer 11

In heart failure and atrial fibrillation

Question 12

What is the direct effect of digoxin?

Answer 12

Shortens the action potential

Question 13

What is the indirect effect of digoxin?

Answer 13

Increases vagal activity which slows SA node discharge and AV node conduction - increases refractory period

Question 14

What effect does digoxin have on the Frank-Starling curve?

Answer 14

Upward and leftward shift

Question 15

When should digoxin never be used?

Answer 15

In hypokalaemia