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Pharmacology fall 2024 > Vasodilators and Angina (Exam III) > Flashcards

Vasodilators and Angina (Exam III) Flashcards

1
Q

Between arteries and veins, which has the greater amount of muscular tone?

A

Arteries

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2
Q

What are the 3 structures that create Arteriolar Tone?

A
  1. Arteries
  2. Arterioles
  3. Precapillary Sphincters
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3
Q

What is the primary purpose of precapillary sphincters? Give an example.

A

Shunting of Blood

ex. SNS activation causing blood to be shunted from GI tract to skeletal muscle.

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4
Q

Contraction of what helps the facilitation of venous blood back to the heart?

A

Skeletal Muscle

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5
Q

What are the two functions of the venous system?

A
  1. Return blood back to the heart
  2. Reservoir for blood volume
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6
Q

How much of total blood volume is contained in the venous system?
How about the splanchnic bed specifically?

A

Venous system = 70% blood volume

Splanchnic Bed = 20-30% blood volume

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7
Q

What is the compliance of veins compared to arteries?

A

Veins have 30x greater compliance (i.e. ability to stretch)

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8
Q

How does the venous system protect cardiac output from dropping?

A

The Venous system serves as a reservoir to counteract changes in blood volume (Preload)

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9
Q

Describe the process of a blood vessel contraction starting with Ca⁺⁺ entering the cell.

A
  1. Ca2+ enters the cell.
  2. The SR releases Ca2+
  3. Ca2+-Calmodulin complex forms
  4. Ca2+-Calmodulin potentiates MLCK
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10
Q

What important secondary messenger is inhibitory to smooth muscle contraction?

A

cAMP

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11
Q

What is the reason for pain in angina pectoris?

What drug provides immediate relief for this?

A

Accumulation of metabolites (lactic acid) due anaerobic metabolism in myocardial ischemia.

Nitroglycerin

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12
Q

What drugs are prophylactic for angina pectoris?

A

β-blockers and CCB’s

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13
Q

Describe classic angina.
What usually brings about this form of angina?

A

“Exertional Angina” which is characterized by ischemia from ↑ oxygen requirement (usually exercise)

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14
Q

What is Variant Angina?

What other names exist for this condition?

What causes this angina? How prevalent is it?

A
  • Myocardial Ischemia secondary to ↓O₂ delivery from coronary vasospasm.
  • Vasospastic or Prinzmetal angina.
  • Idiopathic and transient. (only 2% of angina cases)
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15
Q

What form of angina is a medical emergency?

When is this angina felt?

A

Unstable Angina

Pain is felt at rest.

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16
Q

What pharmacologic therapy is best for variant angina?

A

CCBs

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17
Q

Which two factors most greatly influence the oxygen requirements of the heart?

A
  1. Heart Rate
  2. Contractility
18
Q

Where do we see an initial best response from nitrates and nitrites?

Where would we see a response with increased dosages?

Where would we see an effects, but less than the two aforementioned responses?

A

Large Veins

Large Arteries

Arterioles and precapillary sphincters

19
Q

What is the mechanism of action of nitroglycerin?
What is the bioavailability of nitroglycerin?
How is nitroglycerin metabolized?
Where is nitroglycerin excreted?

A
  • Nitric Oxide (NO) release in vascular smooth muscle.
  • 15-20% bioavailability (sublingual or IV route needed)
  • Nitrate Reductase in the liver
  • Kidneys
20
Q

What is the mechanism of action of Nitric Oxide in causing smooth muscle relaxation?

A
  1. NO released from endothelial cells
  2. ↑ Guanylyl cyclase (GC)
  3. GTP → cGMP (by GC)
  4. cGMP → Myosin-LC
  5. Relaxation
21
Q

Name a PDE-5 (Phosphodiesterase-5) Inhibitor.

How do PDE-5 Inhibitors work?

A

Sildenafil

PDE-5 Inhibitors block Phosphodiesterase-5 from converting cGMP to GMP.

cGMP potentiates relaxation.

22
Q

What is the T1/2 of nitroglycerin?
How does this compare to dinitroglycerin?

A

Trinitroglycerin T1/2: 2-8 mins
Dinitroglycerin T1/2: 3 hours

23
Q

Are there any mononitro forms of nitroglycerin available? What are there benefits?

A

Isosorbide dinitrate
100% bioavailability

24
Q

What are the “good” actions of nitroglycerin?

A

↑ venous capacitance
↓ preload, CO, overall heart size

25
Q

What is the biggest side effect of nitroglycerin?

What dangerous side effects need to be monitored for with nitroglycerin use?

A
  • Headaches
  • Reflex Tachycardia
  • Methemoglobinemia - Nitrate-Hgb binding (preventing O₂ binding)
26
Q

Describe the relevance of someone working in a nitrate factory.

A

Continuous nitrate exposure can cause tolerance to nitrates. 8-hour off periods are needed.

27
Q

What hematological toxicity of nitrates can occur with patients?

Why is this dangerous?

Conversely, when can this be an antidote for a certain condition?

A

methemoglobinemia

Hgb molecules on RBCs develop low affinity for O₂ and can develop pseudocyanosis at very high levels.

Antidote for cyanide poisoning due to affinity for cyanide.

28
Q

Which drug is the prototypical dihydropyridine calcium channel blocker?

Which two other CCB’s should be known?

A
  • Nicardipine
  • Verapamil and Diltiazem
29
Q

What specific type of Ca⁺⁺ channel do CCB’s most commonly bind to when eliciting their effects?

A

L-type Ca⁺⁺ channels causing decreased opening frequency.

30
Q

Which two CCB’s can be used for cardiac effects?
Which one is completely cardio-specific?

A

Diltiazem (smooth muscle & cardiac) and Verapamil (cardio-specific)

31
Q

What 3 major effects would Ca⁺⁺ channel blockade have on the heart?

A
  1. ↓ Contractility
  2. ↓ SA node rate
  3. ↓ AV node conduction
32
Q

What major uses do CCB’s have?

A

Treating HTN and angina.

33
Q

How do β-blockers treat angina?

A

↓ CO = ↓ cardiac demand

34
Q

Name β-blockers in order of best-to-worst for treatment of angina.

A
  1. 3rd gen Vasodilatory (Nebivolol)
  2. 2nd gen β1selective (Metoprolol)
  3. 1st gen non-selective (Propanolol)
35
Q

How do pFOX inhibitors work?

A

↓ FOX (Fatty Acid) metabolism, ↑ glucose metabolism

Fatty acid metabolism requires ↑O₂ vs glucose.

36
Q

Which vasodilators are contraindicated for angina and why?

A
  1. Hydralazine & Minoxidil (reflex ↑HR)
  2. Nitroprusside (↑ toxicity)
  3. Fenoldepam (reflex ↑HR)
37
Q

Modifying which 3 risk factors affects coronary artery disease (and thus angina) the most?

A

Smoking, HTN, and HLD.

38
Q

What should be known about utilization of nitrates with or without β-blockers and CCB’s in the treatment of angina?

A

Nitrates work better when paired with BB’s or CCB’s.

39
Q

What receptors are in the epicardial coronary arteries?

A

α-1 and β-1

40
Q

What receptors are in the microarteries of the heart?

A

β2 primarily (a little bit of α-2)

41
Q

Why would a β-1 selective drug be much better for heart failure?

A

β2 receptors dilate micro

Pharmacology fall 2024 (23 decks)

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