Inotropes and vasopressors

Question 1

The following drugs act on α1-receptors
T/F
Dobutamine

Answer 1

True. Dobutamine acts on α- and β-adrenergic receptors, but has a much weaker α action.

Question 2

The following drugs act on α1-receptors
T/F
Ephidrine

Answer 2

True. Ephedrine acts on α- and β-adrenergic receptors.

Question 3

The following drugs act on α1-receptors
T/F
Adrenaline

Answer 3

True. Adrenaline acts on α- and β-adrenergic receptors.

Question 4

The following drugs act on α1-receptors
T/F
Isoprenaline

Answer 4

False. Isoprenaline is a β-receptor agonist.

Question 5

The following drugs act on α1-receptors
T/F
Levosimendan

Answer 5

False. Levosimendan improves contractility by increasing myocardial sensitivity to calcium, but it also relaxes vascular smooth muscle by opening ATP-sensitive potassium channels causing peripheral vasodilatation.

Question 6

The following have some positive inotropic action
T/F
Dopamine

Answer 6

True. Dopamine has positive inotropic properties via β-adrenergic action.

Question 7

The following have some positive inotropic action
T/F
Potassium

Answer 7

False

Question 8

The following have some positive inotropic action
T/F
Phenylephrine

Answer 8

False. Phenylephrine is a pure α-adrenergic agonist.

Question 9

The following have some positive inotropic action
T/F
Theophylline

Answer 9

True. Theophylline is a non-selective phosphodiesterase inhibitor and works in a similar way to milrinone and enoximone.

Question 10

The following have some positive inotropic action
T/F
Glucagon

Answer 10

True. Glucagon works via Gs-protein receptors which increase cAMP levels. It is only rarely used in the management of β-blocker overdose.

Question 11

T/F

Ephidrine Causes increased noradrenaline release from nerve terminals

Answer 11

True Ephedrine has mixed α- and β- adrenergic action. It also increases noradrenaline release from nerve endings and inhibits monoamine oxidase from breaking down noradrenaline

Question 12

T/F

Ephidrine Displays tachyphylaxis

Answer 12

True. Tachyphylaxis occurs as noradrenaline stores are depleted

Question 13

T/F

Ephidrine Increases systemic vascular resistance

Answer 13

True

Question 14

T/F

Ephidrine Crosses the placenta

Answer 14

True

Question 15

T/F

Ephidrine Has bronchoconstrictor activity

Answer 15

False α-adrenergic action causes an increase in systemic vascular resistance whilst β2 action causes bronchodilatation

Question 16

The following drugs work via G-protein receptors:

Dopamine

Answer 16

True. Dopamine works at α- and β- receptors which are both G-protein coupled.

Question 17

The following drugs work via G-protein receptors:

Levosimendan

Answer 17

False. Levosimenden binds to Troponin C.

Question 18

The following drugs work via G-protein receptors:

Dopexamine

Answer 18

True. Dopexamine works at α- and β- receptors which are both G-protein coupled.

Question 19

The following drugs work via G-protein receptors:

Milrinone

Answer 19

False. Milronone is a selective phosphodiesterase III inhibitor.

Question 20

The following drugs work via G-protein receptors:

Digoxin

Answer 20

False. Digoxin works by inhibiting the sodium-potassium ATPase pump.

Question 21

T/F; Dobutamine Is structurally similar to dopamine

Answer 21

False

Dobutamine is structurally similar to isoprenaline

Question 22

T/F; Dobutamine Activates adeylate cylcase

Answer 22

True

works via Gs-protein receptors that activate adenylate cyclase

Question 23

T/F; Dobutamine Has a selective action on β-adrenoreceptors

Answer 23

False

It has weak action on α-receptors

Question 24

T/F; Dobutamine Has a half-life of 2 minutes

Answer 24

True

Question 25

T/F; Dobutamine Increases the left ventricular end-diastolic pressure

Answer 25

False
It decreases left ventricular end-diastolic pressure via its action on peripheral β2-receptors. β2-linked peripheral vasodilatation reduces venous return