B / 8 : Drugs influencing the oxygen demand and oxygen supply of the heart

Question 1

Which categories of drugs decrease O2 demand of the heart? (3)

Answer 1

• Beta blockers (less contractile force)
• ACE inhibitors (decreased BP)
• Thiazide diuretics (decreased BP)

Question 2

Which categories of drugs increase the O2 supply of the heart? (3)

Answer 2

• Beta blockers (bradycardia : prolonged diastole)
• Nitrates (coronary vasodilation)
• Dihydropyridines (coronary vasodilation)

Question 3

Nitroglycerin, isosorbide mononitrate
- MOA
- Effect
- Indication
- Contraindication
- SE
- Extra

Answer 3

• Nitrate
• Vasodilation causes reduced preload and decreased cardiac work & demand
• For acute angina, acute coronary syndrome, hypertensive crisis
• PDE5 inhibitors ingestion, cardiac tamponade
• Syncope, hypotension, reflex tachycardia
• Rapid onset : 1 min

Question 4

Why are nitrates contraindicated for cardiac tamponades?

Answer 4

The already compromised diastolic filling may be aggravated by reduced venous return

Question 5

Nitroglycerin dose

Answer 5

0.5 mg sublingual

Question 6

How do nitrates decrease cardiac work?

Answer 6

• Nitrates release NO within the smooth muscle
• Increased cGMP by soluble guanylyl cyclase
• Dephosphorylation of myosin light chain
• SM relaxation
• Vasodilation
• Decreased preload

Question 7

How is isosorbide-mononitrate different from nitroglyceride?

Answer 7

It is an oral nitrate while nitroglyceride is taken via sublingual absorption, transdermal patch

Question 8

Trimetazidine
- MOA
- Effect
- Indication
- ROA

Answer 8

• Inhibits beta-oxidation of fatty acids
• Improves myocardial glucose utilization, prevents decrease in intracellular ATP
• For long term treatment of angina
• Oral

Question 9

Ivabradine
- MOA
- Effect
- Indication
- ROA

Answer 9

• Funny current inhibitor in the SA node
• Na current in SA node decreases, causes decreased HR and cardiac work, decreases O2 demand
• For stable angina, chronic HF
• Oral

Question 10

Which drugs are known to improve microcirculation?

Answer 10

• Ca2+-dobesilate
• Cilostazol
• Cinnarizine
• Vinpocetine
• Pentoxifylline
• Nicergoline

3C-VPN

Question 11

Vinpocetine
- MOA
- Effect
- Indication
- ROA

Answer 11

• Inhibitor of Na and Ca channels
• Increases cerebral perfusion
• For tinnitus, dizziness
• Oral, parenteral

Question 12

Nicergoline
- MOA
- Effect
- Indication
- ROA

Answer 12

• alpha 2 antagonist (vasodilation), platelet aggregation inhibitor
• Increases cerebral circulation
• For stroke rehabilitation, alzheimer’s disease
• Oral, parenteral

Question 13

Pentoxifylline
- MOA
- Effect
- Indication
- ROA

Answer 13

• Rheological agent
• Reduces viscosity of blood and increases deformability of RBCs
• Atherosclerotic and diabetic circulatory diseases, memory deficits
• Oral, parenteral

Question 14

Ca2+-dobesilate
- Effect
- Indication
- ROA

Answer 14

• Decreased blood vessel permeability
• For chronic venous insufficiency, diabetic retinopathy
• Oral

Question 15

Cilostazol
- MOA
- Effect
- Indication
- Side effects
- ROA

Answer 15

• PDE3 inhibitor
• Decreases platelet aggregation + vasodilation
• Claudicatio intermittens (narrowed or blocked arteries)
• Coronary steal syndrome
• Oral

Question 16

Cinnarizine
- MOA
- Effect
- Indication
- ROA

Answer 16

• Ca channel blocker and anti-histaminic
• Reduce neurogenic inflammation, promote cerebral perfusion
• For migraines, nausea associated with motion sickness
• Oral