CVS drugs

Question 1

what are the 4 different classes of CVS drugs?

Answer 1

I = drugs that block voltage sensitive sodium channels
II = drugs that block beta-adrenoreceptors (beta blockers)
III = drus that block potassium channels
IV = drugs that block calcium channels

Question 2

1. what is the suffix for beta blockers?
2. what is the action of beta blockers?
3. what condition are beta blockers used to treat?

Answer 2

1. -lol
2. slows conduction at AV node and makes rising phase of AP less steep = slows heart
3. useful in treating an MI to reduce myocardial ischaemia, prevent tachycardia, atrial fibrilation

Question 3

1. what is the use of drugs which block voltage-dependent Na+ channels?
2. what is an example of a drug which blocks voltage-dependent Na+ channels?
3. why do these drugs have little effect in normal cardiac tissue?
4. what can lidocaine be used to treat?

Answer 3

1. block voltage-gated Na+ channels in open or inactive state - preferentially block damaged depolarised tissue = slows heart
2. lidocaine
3. dissociates rapidly + only mild Na+ channel block
4. ventricular tachycardia (dont give following MI)

Question 4

1. what is the suffix of calcium channel blockers?
2. what is the action of calcium channel blockers?
3. what can calcium channel blockers be used to treat?

Answer 4

1. -dipine, -zem, or -amil
2. decrease slope of action potential at SAN, decrease AV nodal conduction and negative ionotropy = lowers BP and HR
3. tachycardia, hypertension, angina

Question 5

1. what is the action of drugs that block K+ channels?
2. what can K+ channel blockers be used to treat?

Answer 5

1. prolong action potential so absolute refractory period is longer, prevents another action potential happening to soon
2. tachycardia associated with Wolff-Parkinson-White syndrome or ventricular arrhythmias post MI

Question 6

1. what is the action of adenosine?
2. what is adenosine used to treat?

Answer 6

1. given IV, acts on A1 receptors in AV node but has short half-life, enhances K+ conductance
2. anti-arrhythmic, useful for terminating re-entry superventricular tachycardia

Question 7

1. what is the suffix of ace-inhibitors?
2. what is the action of ace-inhibitors?
3. what are ace-inhibitors used to treat?
4. what is an alternative drug if patients cant tolerate ace-inhibitors?

Answer 7

1. -pril
2. block the enzyme responsibile for converting angiotesin I to angiotensin II so decreases Na+ and water reabsorption in kidney and arterial vasoconstriction = lowers BP by lowering afterload and preload
3. chronic heart failure
4. angiotensin II receptor blockers

Question 8

1. what is the suffix of diuretics?
2. what is the action of diuretics?
3. what is diuretics used to treat?

Answer 8

1. -ide
2. decrease Na+ and water reabsorption in kidney = lowers BP
3. hypertension + congestive heart failure

Question 9

1. what is an example of a cardiac glycosides?
2. what is the action of cardiac glycosides?
3. what is cardaic glycoside used to treat?

Answer 9

1. digoxin
2. Na+/Ca2+ exchanger drives Ca2+ out of cell, cardiac glycosides block Na+/K+ATPase which is responsible for setting up the electrochemical gradient of Na+/Ca2+ exchanger, rise in intracellular Ca2+, positive ionotropy
3. heart failure, atrial fibrilation

Question 10

1. what is the action of organic nitrate?
2. why do nitrates preferentially act on veins?
3. what are organic nitrates used to treat?
4. what is an example of an organic nitrate?

Answer 10

1. organic nitrates react with thiols to produce nitrogen dioxide which produces nitric oxide, nitric oxide activates guanylate cyclase which increases cGMP which lowers intracellular Ca2+ = powerful vasodilator
2. less endogenous nitric oxide in veins
3. angina, may increase blood supply to heart if it acts on arterioles
4. GTN spray