Cardio Pharmacology

• When is Heparin used?

  •Before and after certain surgeries or procedures where the risk of clotting is high

  •Stop the growth of existing clots and prevent them from causing harm
• What is the mechanism of action of heparin?

  Specifically binds to antithrombin, a natural protein in your blood that inhibits clotting.
• Why can't heparin cross the GI epithelial layer?

  It's negatively charged
• Who is contraindicated to take heparin?

  •People with bleeding disorders

  •People with brain or spinal cord injuries

  •Taking NSAIDs or anti-platelet medications
• What are the functions of warfarin?

  • prevent strokes in people with atrial fibrillation and other conditions that increase the risk of clotting
  • •Prevents blood clots around artificial heart valves
• Describe the mechanism of action of warfarin?

  Inhibition of vitamin K reductase, which reduces the levels of active clotting factors.
• How should warfarin be administered?

  It can be administered orally because it is 100% bioavailable and 99% protein bound.
• What enzyme metabolizes warfarin?

  Cytochrome P450 (CYP2C9)
• Who is contraindicated against taking warfarin?

  Individuals taking another p450 drug, pregnant, or genetically deficient in protein C or protein S
• How should heparin and warfarin be managed clinically?

  Heparin adminsitered during hospital recovery and warfarin taken at home.
• Describe Class 1A Antiarrhythmics?

  Shorten the action potential duration and reduce the rate of rise of the action potential by blocking sodium channels in the heart, making it harder for the cells to depolarize and conduct electrical signals.
• Describe Class 1B Antiarrhythmics?

  By blocking sodium channels, they slow down the conduction of electrical signals through the heart
• Describe Class 1C Antiarrhythmics?

  They cause a marked slowing of conduction in heart tissue, primarily by blocking sodium channels during the depolarization phase, but they have minimal effect on the action potential duration.
• What are class 1A Antiarrhythmics used for?

  Supraventricular arrhythmias, such as atrial fibrillation and flutter, and some specific types of ventricular tachycardia.
• What are Class 1B Antiarrhythmics used for?

  Ventricular arrhythmias, such as ventricular tachycardia and fibrillation
• What are Class 1C Antiarrhythmics used for?

  Atrial and ventricular arrhythmias, including atrial fibrillation, atrial flutter, and ventricular tachycardia
• Class 1A Antiarrhythmics include: Quinidine, procainamide, and disopyramide.
• Class 1B Antiarrhythmics include: Lidocaine, mexiletine, and phenytoin
• Class 1C Antiarrhythmics include: Flecainide and propafenone.
• What are Class 2 Antiarrhythmics used for?


  Supraventricular arrhythmias
• Describe the mechanism of action of Class 2 Antiarrhythmics?

  Blocking beta-adrenergic receptors in the heart which are activated by adrenaline and noradrenaline; therefore, decrease heart rate and the force of contraction.
• Which drugs are in Class 2 Antiarrhythmics?


  Propranolol, metoprolol, atenolol, and bisoprolol
• What are Class 3 Antiarrhythmics used for?


  Atrial and ventricular arrhythmias, including atrial fibrillation, atrial flutter, and ventricular tachycardia
• What are Class 3 Antiarrhythmics mechanism of action?

  Block potassium channels in heart cells, which are responsible for repolarization, and prolong refractory period.
• Class 3 Antiarrhythmic drugs include: amiodarone (Cordarone) and sotalol (Betapace) dofetilide, and ibutilide.
• Class 4 Antiarrhythmics are used for treating Supraventricular arrhythmias, especially those involving the SA and AV nodes
• Describe mechanism of action of Class 4 Antiarrhythmics?

  L-type calcium channels in the heart, which are involved in the influx of calcium ions, are targeted to slow down
• Verapamil is a Class 4 antiarrhythmic.
• What is adenosine useful for?

  Supraventricular tachycardia and Paroxysmal supraventricular tachycardia (PSVT)
• Adenosine activates specific G protein–coupled adenosine receptors. These receptors act to activate of acetylcholine-sensitive potassium channels and blockade calcium influx in the SA node, atrium, and AV node. Therefore, it slows or completely stops AV node conduction for a couple seconds.
• Magnesium sulfate is Useful for preeclampsia and torsades de pointes arrhythmias
• Magnesium ions compete with calcium ions at L-type calcium channels in heart cells, potentially reducing calcium influx and modulating electrical activity. This can help normalize heart rhythm in specific arrhythmias.
• Quinidine can cause what effects seen on the ECG?

  Widening of QRS complex and lengthening of QT and PR intervals, incidences of PVCs
• Side effects of quinidine include?

  Fatigue, headache, light-headedness, hypotension, tachycardia, diarrhea, and cinchoism
• Contraindications to quinidine: myasthenia gravis, conduction defects
• Quinidine-induced digoxin toxicity occurs in a significant fraction of patients.
• Co-administration of anticholinergics with quinidine results in additive anticholinergic effects.
• An agent that slows AV nodal conduction (a β-adrenergic blocker or a Ca2+ channel blocker) should be used in conjunction with quinidine to prevent an excessively rapid ventricular response in patients with atrial flutter or other supraventricular tachycardias.
• lupus-like syndrome may occur after prolonged use of procainamide.
• Procainamide does not alter plasma levels of digoxin.