MCQ's: CVS 1 Flashcards
ESMOLOL:
Select true or false for each of the following statements.
A. Is useful in the treatment of essential hypertension.
B. Has a half life of 2 minutes.
C. Is largely excreted unchanged in the urine.
D. Acts selectively on beta-1 receptors.
E. Possesses intrinsic sympathomimetic activity.
A. False. It is only given intravenously and has a short half life.
B. False. It is around 10 minutes.
C. False. It is rapidly metabolised by red-cell esterases.
D. False. It is non-selective.
E. False.
The following statements about selective phosphodiesterase (PDE) inhibitors are true:
- Select true or false
A. Inhibition of isoenzyme family No. I effects a positive inotropic action.
B. Inhibition of isoenzyme family No. III results in clinically important bronchodilatation.
C. They increase myocardial oxygen consumption
D. Tachycardia is a common occurrence
E. Their use increases blood pressure as a result of increased cardiac output and systemic vascular resistance.
A. False. Inhibition of isoenzyme family No. III results in positive inotropy.
B. False. Bronchodilatation does occur but not to a clinically significant degree.
C. False. There is unchanged or even slightly reduced myocardial oxygen consumption as systemic vasodilation reduces left ventricular systolic wall tension.
D. True. There is a reflex tachycardia, reduced SVR - causes hypotension.
E. False. Hypotension is often seen as a result of reduced systemic vascular resistance due to smooth muscle relaxation.
Milrinone:
- Select true or false for each of the following statements.
A. Is one of the bipridine derivative group of phosphodiesterase inhibitors.
B. Is structurally related to amrinone
C. It’s short half life makes it well suited to use as an infusion
D. Doses should be reduced in end stage renal failure
E. Is incompatible with intravenous furosemide when given through the same cannula
A. True. Enoximone and piroximone are imidazolone derivatives.
B. False.
C. False. It is used in infusion form but has a terminal half life of 2.5 hours. A loading dose is required.
D. True. 80% is excreted unchanged via the kidneys and dose reductions are required when the creatinine clearance falls to less than 30 ml/min.
E. True.
Clonidine effect on ADH?
Inhibits ADH release, therefore has a diuretic effect on humans.
Ephedrine is a catecholamine?
It does not have a hydroxyl substitution of the benzene ring, and therefore cannot properly be called a catecholamine.
Ephedrine: how many isomeric forms?
It can exist in four isomeric forms but the only active one is the l-form.
Ephedrine is supplied as the racaemic mixture or simply in the l-form.
Regarding digoxin:
Select true or false for each of the following statements.
A. 25% of the oral dose is absorbed
B. 95% is bound to plasma proteins
C. It is largely excreted unchanged in the urine
D. Hypokalaemia may cause raised serum levels of digoxin
E. Toxicity may result in Mobitz type II heart block
A. False. It is well absorbed orally.
B. False. There is insignificant binding to plasma proteins.
C. True.
D. True.
E. True. All forms of heart block have been recorded in digitalis toxicity.
The following drugs cause prolongation of the Q-T interval:
Select true or false for each of the following statements.
A. Sotalol B. Quinidine C. Verapamil D. Flecainide E. Disopyramide
SOTALOL, QUINIDINE, DISOPYRAMIDE
A.True. Sotalol, a beta blocker, posesses class III activity, and both quinidine and disopyramide have class 1A actions with mild class III activity prolonging the cardiac action potential and hence the Q-T interval.
B. True.
C. False.
D. False. Flecainide, a class IC antiarrhythmic agent does not directly prolong the Q-T interval.
E. True.
The following drugs have potassium sparing diuretic effects:
Select true or false for each of the following statements.
A. Enalapril B. Frusemide C. Triamterene D. Spironolactone E. Flecainide
Enalapril, Triamterene, Spironolactone
ACE inhibitors - The angiotensin converting enzyme inhibitors have an anti-aldosterone effect.
They act as weak potassium sparing diuretics and concomitant use of such drugs should be undertaken with care.
Sodium Nitroprusside:
? reaction to light
? what mediates reflex tachycardia
? veno and vasodilation T/F
It slowly decomposes when exposed to light, its decomposition is surprisingly slow: 50% of its activity remains after 2 days exposure to light.
Baroreceptor mediated rise in HR
False
How is sodium nitroprusside broken down?
Breakdown occurs in red blood cells with production of cyanomethaemoglobin.
