Cardiovascular Drugs - Module 7

Cardiovascular Drugs - Module 7

• Cardiovascular medications manage arrhythmias, angina (chest pain), blood pressure, cholesterol, and blood clots.

Acute Coronary Syndrome (ACS)

• ACS is a range of clinical symptoms linked to acute myocardial infarction (NSTEMI & STEMI) and angina (stable & unstable [UA]).
• In ACS, a plaque in a coronary artery ruptures or erodes, triggering the clotting cascade.
• A blood clot forms, obstructing the artery and halting blood and oxygen flow to the cardiac muscle.

Plaque Formation

• Atherosclerotic plaque develops within the artery walls.
• The endothelium (artery lining) is affected.

Lipid Deposition

• Lipid deposition is a factor in plaque formation.
• Endothelial injury is a site of lipid deposition.

Thrombus Formation

• Plaque rupture and fissure initiate thrombus formation.

Platelet Adhesion

• Platelets adhere to the injured arterial wall.

Embolus Formation

• A thrombus can detach and travel, becoming an embolus.

Occlusion Causes Infarction

• A thrombus blocks blood flow, leading to infarction.
• Collateral flow is the alternative blood flow path.

ACS Management

• Initial evaluation: ABCs, O2, IV, monitor vital signs, pulse oximeter, blood pressure, history, assess discomfort, and obtain 12-lead ECG.
• Antiplatelet and anticoagulants, aspirin, nitroglycerin, morphine, pain management, oxygen are used.
• 12-lead ECG evaluation - Normal, ischemia, injury
• Determine reperfusion strategy
• Initial interventions, pain management, Get baseline cardiac biomarker levels, electrolytes, coagulation studies, chest x-ray

ACS Drugs - MONA

• Providers use the acronym MONA to help remember the initial treatment options:
  • M: Morphine
  • O: Oxygen
  • N: Nitroglycerin
  • A: Aspirin
• Drugs are not given in the order MONA, but rather OANM.

Oxygen

• Oxygen (O2) is administered if the patient's oxygen saturation is below 94%.

Aspirin

• The usual dose for ACS is 160-325 mg of chewable aspirin to hasten absorption.
• It reduces platelet aggregation, minimizing the risk of further coronary artery blockage or recurrence of an ischemic event.

Nitroglycerin

• Used to resolve chest pain caused by ACS.
• Administered sublingually (under the tongue) via spray or rapidly dissolving tablet.
• The dose can be repeated every 5 minutes if the initial dose is ineffective.
• Nitroglycerin relaxes vascular smooth muscle beds, particularly in coronary arteries, to improve blood flow to ischemic areas and decrease myocardial oxygen consumption.
• Patient's blood pressure must be monitored continuously due to its vasodilation effects. Usage is contraindicated for systolic blood pressure below 90 mm/Hg.

Morphine

• Administered in cases where nitroglycerin fails to relieve chest pain
• Given every 5 minutes as an IV push.
• The maximum dose is 10mg.
• It acts on opioid receptors, reducing pain perception and ventricular preload, lowering cardiac oxygen needs.

Antihypertensive Drugs

• Drugs for blood pressure control:
  • Alpha1 blockers, ending in "lol" (e.g., doxazosin, prazosin, terazosin)
  • Beta blockers, ending in "lol" (e.g., propranolol, acebutolol, esmolol)
  • ACE inhibitors, ending in "pril" (e.g., captopril, enalapril, lisinopril, quinapril, ramipril, benazepril, fosinopril)
  • Angiotensin receptor blockers (ARBs), ending in "sartan" (e.g., valsartan, losartan, irbesartan, telmisartan, candesartan)
  • Calcium channel blockers (CCBs), ending in "pine" (e.g., verapamil, diltiazem, nifedipine)
  • Diuretics
  • Vasodilators (e.g., hydralazine, sodium nitroprusside).

Beta Blockers (Class II)

• Beta blockers target beta-1 receptors in the heart linked to calcium channels.
• This mechanism reduces calcium influx, affecting heart rate and contractility.

ACE Inhibitors

• ACE inhibitors block the conversion of angiotensin I to angiotensin II, inhibiting vasoconstriction.
• They decrease blood pressure and reduce workload for the heart.

Calcium Channel Blockers (Class IV)

• These drugs affect the SA and AV nodal conduction and decrease myocardial contractility.

Antihyperlipidemic Drugs (Statins)

• Statins lower LDL cholesterol by blocking HMG CoA reductase, an enzyme that's required to synthesize cholesterol.
• They minimize the risk of heart attack and stroke.

Lipoproteins

• Lipoproteins transport lipids within the body.
• LDLs: "bad" cholesterol, deposit in the arteries.
• HDLs: "good" cholesterol, transport cholesterol out of the arteries.

Platelet Inhibitors

• Platelet inhibitors prevent aggregation, important in preventing clot formation in cases of MI or CVA.

Glycoprotein IIb/IIIa Inhibitors

• These drugs block the GP IIb/IIIa receptor, preventing platelets from aggregating.
• Used in cases of unstable angina or significant stenosis.

Anticoagulants

• Anticoagulants prevent blood clot formation.
• Unfractionated heparin and LMWH inhibit thrombin, preventing fibrin formation and platelet activation.
• Heparin (unfractionated and LMWH) and warfarin are used to prevent blood clots.

Fibrinolytics

• Fibrinolytics break up existing blood clots (thrombi) in arteries and veins.

Occlusion Mechanism

• Clots block blood flow, leading to decreased oxygen supply to heart tissues.

tPA Mechanism

• tPA activates plasminogen to plasmin, which then dissolves the fibrin of blood clots.