Pharma MCQ 9

Question 1

Magnesium infusion causes:

1. Increased myocardial contractility
2. Neuromuscular blockade
3. Hypertension
4. CNS depression
5. Muscle twitching

Answer 1

1. Increased myocardial contractility - FALSE. Opposes action of calcium.
2. Neuromuscular blockade -TRUE
3. Hypertension - FALSE - opposes Ca action.
4. CNS depression - TRUE
5. Muscle twitching - FALSE, Magnesium also causes muscle weakness, depressed tendon reflexes and has anticonvulsant activity.

Question 2

Main function of sodium nitroprusside?

Answer 2

SNP is a potent vasodilator:
- reduces SVR

• reduces pulmonary vascular resistance
• arterial hypotension and reflex tachycardia occur.

Question 3

How can sodium nitroprusside effect PaO2?

Answer 3

Can decrease this by blocking hypoxic pulmonary vasoconstriction and increase intrapulmonary shunt.

Question 4

Dopamine:

- is an intermediate precursor of which hormone?

Answer 4

Dopamine is metabolised to NORADRENALINE

by the enzyme dopamine beta-hydroxylase.

Question 5

How does Dopamine increase cardiac output?

Answer 5

Dopamine is also an agonist at alpha- and beta- adrenergic receptors.

With increasing doses, direct beta- adrenergic effects cause increased cardiac output and alpha-adrenergic effects cause vasoconstriction.

Question 6

Dopamine renal effects?

Answer 6

Dopamine increases renal blood flow, GFR and so increases sodium excretion.

Question 7

Dopamine effect on mesenteric and splanchnic vessels?

Answer 7

Dopamine is an agonist at dopaminergic (D1) receptors

which mediate

splanchnic vasodilatation and

increase renal

and mesenteric blood flow.

Question 8

Ephedrine effect on uterine blood flow?

Answer 8

In contrast to pure vasoconstrictor drugs, uterine blood flow is maintained with ephedrine.

Question 9

Which is more potent, atropine or glycopyrrolate?

Answer 9

Glyco more potent

Question 10

Atropine effect on IOP?

Answer 10

It is a mydriatic and increases intraocular pressure.

Question 11

Atropine effect on physiological dead space?

Answer 11

Atropine is a bronchodilator and so increases anatomical dead space and therefore

—-»> increases physiological dead space.

Question 12

Salbutamol effect on the activity of adenylate cyclase?

Answer 12

Increases adenylate cyclase through its action as a bronchial beta-2 receptor agonist.

Question 13

Atropine mechanism of action on receptors.

Answer 13

Atropine is a non-selective ANTAGONIST at all muscarinic receptor subtypes.

M2 muscarinic cholinoceptors predominate in the heart to modulate heart rate and impulse conduction.

M2 and M3 subtypes are thought to predominate in the bronchial tree.

Question 14

How do antibiotics interfere with neuromuscular transmission?

Answer 14

1. blocking open channels
2. interfering with release of acetylcholine
3. Antibiotics interfere with neuromuscular transmission by a number of pre and post-junctional mechanisms including receptor site competition, interference with ACh release and open channel block.

Question 15

True or false: Protamine is a basic protein.

Answer 15

Protamine is a basic protein which binds to and antagonises heparin (a strongly acidic drug).

Question 16

How much Heparin is antagonised by 1mg Protamine?

Answer 16

1 mg protamine antagonises the effects of 100 IU heparin

Question 17

Protamine effect on heart?

Answer 17

It is a potent vasodilator and myocardial depressant.

Question 18

Do large doses of Mannitol, increase or decrease ECF Osmolarity?

Answer 18

Increase

Question 19

True or False: Furosemide decreases the ototoxicity of aminoglycoside antibiotics.

Answer 19

False - Furosemide increases renal concentrations of aminoglycosides and so increases their toxic effects..

Question 20

Is Protamine contra-indicated in hepatic failure?

Answer 20

No