Cardio: Anti-anginal Drugs

Question 1

• Phenylalkylamine
• L-type Calcium channel blocker
• Cause Coronary Vasodilation and Relief of Spasm
• Slowed Conduction through the AV Node
• May produce AV block when used in combination with β-adrenoceptor antagonists
• Produces peripheral vasodilating effects –> reduce afterload and blood pressure
• Cause, Headache, reflex Tachycardia, Fluid retention

Answer 1

Verapamil (Calan, Isootin, Verelan)

Question 2

• Dihydropyridines calcium channel blockers
• Predominant actions in the Peripheral vasculature
• Decrease Afterload
• Small-decrease in Preload
• Lowers Blood pressure
• Significantly less direct effect on the heart than Verapamil

Answer 2

Nifedipine (Adalat)

Nimodipine

Isradipine

Amlodipine

Felodipine

Nisoldipine

Question 3

• Benzothiazepine Ca²⁺ Channel blocker
• Treats Prinzmetal angina

Answer 3

Diltiazem (Cardizem)

Question 4

Drugs capable of denitration to release Nitric oxide (NO)

Answer 4

Nitroglycerin (Nitrol, Nitrostat)

Isosorbide dinitrate (Isordil)

Isosorbide-5-mononitrate (Imdur)

Amyl Nitrate

Erythrityl tetranitrate (Cardilate)

Question 5

Mechanism of Action for Nitric oxide (NO)

Answer 5

• Nitroglycerin releases NO to activate Guanylyl cyclase
• Leads to the formation of cGMP and activation of cGMP-dependent kinases
• cGMP activates Myosin light chain phosphatase to Dephosphorylate myosin light chain
• Leads to the uncoupling of Myosin and Actin in Smooth muscle cells and thus Vasodilation in Arterioles and particularly in Venules (All vessels)

Question 6

(4) Ways NO reduces Angina

Answer 6

1. Dilation of Systemic venules to decrease the Preload
   → Increase the pressure gradient from the Aorta to the endocardium
   → Increase Coronary blood flow
2. Reduction in Preload reduces the oxygen demand
3. Dilation of the Coronary epicardial vessels only, NO Coronary Steal effect
4. Modest declines in SBP (afterload) are useful in decreasing oxygen consumption

Question 7

NO is used in the treatment of:

Answer 7

• Angina
• Congestive heart failure
• MI

Question 8

NO is contraindicated in pts. w/

Answer 8

• Patients taking Sildenafil (Viagra)
• Hypotension
• Hypertrophic obstructive cardiomyopathy
• Diastolic heart failure

Question 9

Side effects of NO use:

Answer 9

• Heart failure
• AV block
• Bradycardia
• Cardiac arrest
• Cardiac depression
• Orthostatic Hypotension
• Reflex Tachycardia
• Headache
• Blushing
• (High dose) Methemoglobinemia and cyanosis

Question 10

β-Adrenergic receptor antagonists:
β-blocker drugs

Answer 10

• Non-selective β-blockers
  
  • Propranolol (Inderal)​
  • Sotalol
  • Pindolol (Visken)
• β₁-selective blockers
  
  • Atenolol (Tenormin)
  • Acebutolol
  • Bisoprolol

Question 11

Mechanism of action of β-blockers

Answer 11

• Reduce the Heart rate (via automaticity and conduction velocity) to decrease the myocardial O₂ consumption
• Reduce Heart contractility to decrease the myocardial O₂ consumption
• Reduce the Arterial blood pressure to decrease the myocardial O₂ consumption

Question 12

Side effects of β-blockers:

Answer 12

• Asthma
• Erectile dysfuntion
• Depression
• Insomnia
• Contraindicated in Bradycardia, AV block, and Asthma

Question 13

• Non-nitrate coronary vasodilator that interferes with uptake of Adenosine (vasodilator)
• Potentiates the effect of PGI₂ (Prostacyclin, Epoprostenol) and dilates Resistance vessels and inhibits Platelet aggregation
• Prophylaxis of Angina Pectoris
• Causes, possible worsening of Angina, Dizziness, and Headache

Answer 13

Dipyridamole (Persantine)