Drugs

Question 1

Loop Diuretics

Answer 1

Inhibit NaCl reabsorption in the loop of Henle.
Strong and fast acting but short lasting.
eg: frusemide

Question 2

What is the basic idea behind diuretics?

Answer 2

Decrease blood volume
> decrease preload and afterload
>decrease cardiac output
= less strain/O2 demand on heart.

Question 3

Thiazide diuretics

Answer 3

Inhibit NaCl reabsorption in the distal tubule. This leads to decreased water absorption into the blood stream via osmosis.
Safe but weak.
eg: bendrofluazide

Question 4

Potassium sparing diuretics

Answer 4

Weak, usually used in combination with others.
Can ^K
eg: Spirolactone

Question 5

Diuretics - side effects

Answer 5

electrolyte imbalances (Us, Es, hypokalaemia)
Hypotension
^Uric acid

Question 6

B-blockers work by?

Answer 6

inhibiting B1 receptors (sympathetic)
>reduce HR and CO
>reduce work performed by heart
>reduce O2 demands

Question 7

Side effects/worries with beta blockers?

Answer 7

Can mask signs of hypoglycaemia
Cold hands and feet (vasoconstriction in peripheries)
Sleep - nightmares etc
Tiredness
Impotence

DO NOT GIVE TO ASTHMATICS!!!

Question 8

How does dopamine work?

Answer 8

In the opposite way to beta blockers - it increases heart rate and blood pressure.

Question 9

Basic m.o.a of nitrates?

Answer 9

Peripheral vessel dilators -> decrease preload.

Question 10

M.o.a. of Ca channel blockers?

Answer 10

Dilates arteries (including coronary), leading to a reduced afterload and therefore workload and O2 demands of the heart.

Question 11

Amlodipine is a…?

Answer 11

Ca channel blocker

Question 12

ACE-inhibitors do what? How?

Answer 12

Reduce blood pressure.
Prevents vasoconstriction of both arteries and veins.

Blocks angiotensin II (a vasoconstrictor) which leads to reduction in aldosterone.

It can lead to renal failure.

Question 13

What is amiodarone used for and how does it work?

Answer 13

Arrythmias - to reduce and stabilise HR
- in VT/VF arrest

Work by increasing repolarisation time to prolong the action potential.
Acts on: AVnode, purkinje fibres, cardiomyocytes.

Question 14

What is quinidine used for and how does it work?

Answer 14

To reduce and stabilise HR in arrythmias.

Increases action potential threshold and refractory period.
Acts on cardiomyocytes, AVN, purkinje fibres.

Question 15

Atropine: use and basic m.o.a?

Answer 15

Bradycardia

Antagonises (reduces) parasympathetic stimulation
> increases heart rate.

Question 16

Use B-blockers in arrythmias caused by…?

Answer 16

MI
thyrotoxicosis
emotions

Question 17

Uses and basic m.o.a of digoxin?

Answer 17

Heart failure - increases force of contraction
Supraventricular tachycardia (SVT)

blocks Ca+ channels in the AVN and bundle of His

- increases refractory period
- slows conduction

Question 18

Adenosine - when would you use it and what does it cause?

Answer 18

SVT

transient heart block in the AV node.

Question 19

Lignocaine - how does it work and what do you use it in?

Answer 19

0blocks Na+ channels

use in ventricular arrythmias (except VF/VT arrest)

Question 20

What do aspirin and clopidogrel do?

Answer 20

Permanently block platelet activation sites.

Have to wait for new ones ~ long lasting!