Angina drugs

Question 1

Glyceryl trinitrate:

Answer 1

organic nitrate prodrug. Ineffective if swallowed - metabolised to inorganic nitrate in liver.

Question 2

Isosorbide dinitrate:

Answer 2

organic nitrate. More stable than glyceryl trinitrate, so can be swallowed. Risk of developing tolerance.

Question 3

Nicorandil:

Answer 3

activates potassium channels and also NO donator. It is a vasodilator and its mechanism, efficacy and side effects are very similar to glyceryl trinitrate.

Question 4

Nifedipine:

Answer 4

calcium channel blocker. Block of channels is not use-dependent, so more potent on vascular smooth muscle than the heart. Dilatation of arterioles reduces cardiac afterload, reducing cardiac work and O2 need.

Question 5

Verapamil:

Answer 5

a class IV antidysrhythmic drug, also used in angina. Calcium channel blocker. Block is use-dependent, so more potent on the heart than vasculature. Reduces heart rate and cardiac output so cardiac work and O2 needs are reduced.

Question 6

Digoxin:

Answer 6

a positive inotrope. Used in patients who have cardiac failure with a dysrhythmia. Increases vagus nerve (parasympathetic) activity, slowing SA node firing rate and ventricular rate. Contains lactone, steroid and sugar group. Toxic in higher doses!