questions 2

Antianginal Drugs

Topic updated on 09/04/17 7:07am

Cardiovascular Drug Introduction
  • Cardiovascular medications can be broken down into the following categories
    • Antiarrhythmics
    • Antihypertensives
    • Inotropes
    • Vasodilators
    • Diuretics
    • Antihyperlipidemics
    • Anti-plateletes
    • Thrombolytics
  • Symptoms of angina due to myocardium oxygen demand exceeding supply
  • Goal is to ↓ myocardial O2 consumption (MVO2)
    • can achieve by reducing
      • end diastolic volume
      • blood pressure
      • heart rate
      • contractility
      • ejection time
  • Can also ↑ O2 supply to myocardium
  • Main drugs include nitrates, beta-blockers, and calcium channel blockers
  • Examples
    • nitroglycerin, isosorbide dinitrate (also mononitrate), nitroprusside
  • Mechanism 
    • venodilation via generation of endothelial NO
      • results in activation of guanyl cyclase → ↑cGMP → relaxation of smooth muscle 
      • dilate veins >> arteries 
    • ↓ EDV, ↓ BP → ↓ MVO2
    • reflex ↑ in contractility and HR
    • isosorbide mononitrate has highest oral bioavailability
  • Clinical use
    • angina
    • pulmonary edema
    • aphrodesiac and erection enhancer
  • Toxicity
    • orthostatic hypotension
      • especially in combination with other antihypertensives
    • headache
      • due to vasodilation of cerebral arteries 
    • reflex tachycardia
    • tachyphylaxis
    • contraindicated in patients taking vasodilatory medication for erectile dysfunction (e.g. sildenafil)
      • severe hypotension
    • nitroprusside causes cyanide toxicity 
    • "Monday disease" in industrial exposure
      • development of tolerance for the vasodilating action during the work week
      • loss of tolerance over the weekend
      • results in tachycardia, dizziness, headache on re-exposure
  • Examples
    • propanolol, atenolol, metoprolol
  • Mechanism
    • beta-adrenergic antagonism
      • results in ↓ cAMP
    • ↓ contractility, HR, BP→ ↓ MVO2
  • Toxicity
    • impotence, depression, bradycardia
    • pindolol and acebutolol are partial β-agonists
      • contraindicated in angina
Calcium Channel Blockers
  • Examples
    • nifedipine, verapamil, diltiazem
  • Mechanism
    • ↓ vascular smooth muscle contractility
      • result of inhibition of voltage-gated L-type Ca2+ channels
      • also affects cardiac tissue
      • nifedipine is most selective for vasculature
      • verapamil is most selective for heart
        • "Verapamil works on Ventricles"
    • ↓ afterload, ↓ AV node conduction velocity → ↓ MVO2
  • Clinical use
    • angina
    • hypertension
    • arrhythmias (not nifedipine) (see Antiarrhythmics)
    • vasospasm
      • Prinzmetal's angina
      • Raynaud's
  • Toxicity
    • cardiac depression
    • peripheral edema
    • AV block
    • flushing
    • dizziness
    • constipation


Qbank (2 Questions)

(M3.CV.12) A 71-year-old man with a history of BPH is hospitalized for an ST-elevation myocardial infarction and undergoes percutaneous coronary intervention. Upon discharge, he is prescribed aspirin, clopidogrel, prazosin, isosorbide mononitrate, carvedilol, enalapril, and atorvastatin. He is scheduled to follow up with his primary care provider 1 week after discharge. Which of the following is the most likely complication of his drug regimen? Topic Review Topic

1. Torsades de pointes
2. Drug-induced hepatitis
3. Orthostatic hypotension
4. Agranulocytosis
5. Seizure

(M2.CV.40) A 37-year-old female presents to the general medical clinic with chest pain. She reports that the pain occurs at rest and feels as if an elephant is sitting on her chest. She has no other complaints. Her past medical history is significant for migraines but she has no history of smoking, hypertension, hyperlipidemia, or diabetes. Her vital signs are temperature 37 degrees Celsius, HR 70/minute, BP 110/80, RR 16/min, and oxygen saturation 99% on room air. Her physical examination reveals no murmurs. An EKG in the office during one of the episodes reveals the following as shown in figure A. Troponins are positive. She is admitted to hospital and undergoes emergent cardiac catheterization, where she is without obstructive coronary disease, but her symptoms can be provoked with administration of intravenous ergonovine. Which of the following treatments would be appropriate in this patient? Topic Review Topic
FIGURES: A          

1. Furosemide
2. Lisinopril
3. Metoprolol
4. Aspirin
5. Diltiazem


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