Angina

Question 1

List drugs that increase O2 supply.

Answer 1

Nitrates, Ca2+ channel blockers, beta-blockers

Question 2

What is variant angina?

Answer 2

No atherosclerosis, spasm of coronary arteries.

Question 3

List the determinants of myocardial O2 requirement.

Answer 3

HR, contractility, ventricular volume, arterial pressure.

Question 4

Which vessels need to be dilated to decrease O2 demand?

Answer 4

Arteries and veins (coronary dilation increases O2 supply).

Question 5

Which structures to organic nitrate primarily affect?

Answer 5

Vascular smooth muscle in the veins

Question 6

What is the role of SH groups in vasodilations?

Answer 6

Increase NO activity

Question 7

What is the effect of nitrates of different vessels?

Answer 7

Dilation of veins decreases preload, reducing oxygen consumption. Dilation of coronary arteries, increases oxygen availability. At higher doses, arteriolar dilation reduces after-load.
Dilation of collateral vessels (anastomoses) increases blood flow to ischaemic areas (dipyridamole reduces flow to ischaemic areas)

Question 8

What are the limitations of nitrates?

Answer 8

Reflex tachycardia, volatile (other than spray, need to be in closed non-plastic container)

Question 9

Describe the pharmacokinetics of nitrates.

Answer 9

Large hepatic first pass metabolism >90%

GTN given sublingually or transdermally, inactive orally.

Question 10

Compare GTN and isosorbide dinitrate

Answer 10

GTN: sublingual (<30min), transdermal (<24h)

Isosorbide dinitrate: sublingual (<2h), oral (<6h)

Question 11

When is sublingual GTN used?

Answer 11

Treatment of acute angina attack, immediate prophylaxis

Question 12

List the ADRs of nitrates.

Answer 12

Hypotension, tachycardia, headache (changes in CBF), flushing
Tolerance as SH groups are depleted.

Question 13

What is the mechanism of action of sildenafil?

Answer 13

Inhibits PDE V. PDE V normally inactivates cGMP to reduce vasodilation.

Question 14

When are Ca2+ channel blockers used in angina?

Answer 14

Hypertension, tachydysrhythmia (SV)

Best for unstable angina due to coronary spasm, can be used for stable angina.

Question 15

Which Ca2+ channel blocker is best for angina?

Answer 15

Verapamil > diltiazem > nifedipine.

Question 16

List the ADRs of Ca2+ channel blockers.

Answer 16

Cardiac depression, bradycardia, flushing, oedema, dizziness, headache, constipation.

Question 17

What are the clinical uses of beta-blockers?

Answer 17

Angina, hypertension, dysrhythmia, stable HF.

Question 18

What is the effect of beta-blockers in angina?

Answer 18

Decrease O2 demands, decrease in HR increase coronary artery perfusion during diastole

Question 19

List the ADRs of beta blockers.

Answer 19

Resp: bronchoconstriction
CVS: decreased contractility, exercise intolerance, claudication, impotence, sudden withdrawal complications.
Brain: depression, sedations, sleep disturbances
Diabetes: exacerbate and mask hypoglycaemia- promote glycogenesis, block tremor.

Question 20

Which drugs are used for variant angina?

Answer 20

Ca2+ channel blockers, nitrates, beta blockers.

Question 21

Which drugs are used in unstable angina?

Answer 21

Vasodilators, antiplatelets.