Pharmacology Unit 4: Cardiovascular Systems and Hematologic Drugs

Digoxin (Lanoxin®) Classification

A cardiac glycoside used to treat heart failure and certain cardiac arrhythmias.

Digoxin (Lanoxin®) Pre-administration Action

Assess the apical pulse for 1 full minute; hold the medication if the heart rate is less than $60\,bpm$.

Digoxin (Lanoxin®) Toxicity Signs

Visual disturbances (yellow-green halos), nausea, vomiting, anorexia, and bradycardia.

Right Atrium

The heart chamber that receives deoxygenated blood from the systemic circulation via the superior and inferior vena cava.

Right Ventricle (RV)

The chamber that pumps deoxygenated blood to the lungs through the pulmonary artery.

Left Atrium

The heart chamber that receives oxygenated blood from the lungs via the pulmonary veins.

Left Ventricle (LV)

The muscular chamber that pumps oxygenated blood to the rest of the body through the aorta.

Oxygenated Blood Vessels

Vessels that carry blood rich in oxygen, typically arteries (except for the pulmonary artery).

Deoxygenated Blood Vessels

Vessels that carry blood low in oxygen, typically veins (except for the pulmonary veins).

Capillaries

Microscopic vessels responsible for gas exchange between the blood and tissue cells.

Pulmonary Circuit Exception

The pulmonary artery carries deoxygenated blood to the lungs, while the pulmonary veins carry oxygenated blood to the heart.

Sinoatrial (SA) Node

Known as the natural pacemaker of the heart; it initiates the electrical impulse for contraction.

SA Node Location

Located in the upper wall of the right atrium.

Left-Sided Heart Failure Symptoms

Characterized by pulmonary congestion, shortness of breath (dyspnea), and crackles due to fluid backing up into the lungs.

Right-Sided Heart Failure Symptoms

Characterized by peripheral edema, jugular venous distention (JVD), and organ engorgement due to fluid backing up into the body.

Cardiac Glycosides Mechanism of Action (MOA)

Inhibits the $Na^+/K^+$ ATPase pump, increasing intracellular calcium to strengthen myocardial contraction.

Positive Inotropic Effect

An increase in the force or strength of myocardial contraction.

Negative Chronotropic Effect

A decrease in the heart rate.

Absolute Refractory Period

The interval during which a second action potential cannot be initiated, regardless of the strength of the stimulus.

Calcium (Cardiac Role)

Responsible for myocardial contraction and the plateau phase of the cardiac action potential.

Sodium (Cardiac Role)

Responsible for the rapid depolarization phase of the cardiac action potential.

Potassium (Cardiac Role)

Responsible for the repolarization phase; imbalances can lead to life-threatening arrhythmias.

Amiodarone Classification

A Class III antiarrhythmic agent.

Amiodarone Mechanism of Action

Primarily works by blocking potassium channels, thereby prolonging the action potential duration and effective refractory period.

Epoetin alfa (Epogen®, Procrit®)

A recombinant form of erythropoietin that stimulates the production of red blood cells in the bone marrow.

Ezetimibe (Zetia®) Classification

A cholesterol absorption inhibitor.

Ezetimibe (Zetia®) Mechanism of Action

Inhibits the absorption of cholesterol within the small intestine.

Ventricular Fibrillation (V-fib)

A lethal cardiac rhythm characterized by rapid, chaotic electrical activity in the ventricles resulting in no cardiac output.

Atrial Fibrillation (A-fib)

A common arrhythmia characterized by irregular, rapid atrial contractions, increasing the risk for blood clots and stroke.

Anticoagulant Therapy Side Effects

Increased risk of bleeding, localized bruising, and hemorrhage.

Anticoagulant Warning Signs

Bleeding gums, nosebleeds (epistaxis), blood in the urine (hematuria), or black/tarry stools (melena).

Heparin Classification

An indirect thrombin inhibitor (anticoagulant).

Heparin Administration

Administered parenterally, either through intravenous (IV) infusion or subcutaneous injection.

Heparin Antidote

Protamine sulfate.

Warfarin Antidote

Vitamin K.

Blood Pressure Control

Regulated by the nervous system, the kidneys (RAAS), and various hormones that influence blood volume and vascular resistance.

High-Density Lipoprotein (HDL)

Often called "good cholesterol" because it transports cholesterol away from the tissues and back to the liver.

Low-Density Lipoprotein (LDL)

Often called "bad cholesterol" because it contributes to plaque buildup in the arteries (atherosclerosis).

Antiarrhythmics Indications

Used to treat or prevent various disorders of cardiac rhythm, such as atrial flutter, fibrillation, or tachycardia.

Class I Antiarrhythmics

Sodium ($Na^+$) channel blockers.

Class II Antiarrhythmics

Beta-adrenergic blockers.

Class III Antiarrhythmics

Potassium ($K^+$) channel blockers.

Class IV Antiarrhythmics

Calcium ($Ca^{2+}$) channel blockers (CCBs).

Potassium-Sparing Diuretics Benefit

They promote diuresis (water loss) while preventing the excessive excretion of potassium in the urine.

Loop Diuretics vs. Potassium-Sparing Diuretics

Loop diuretics are more potent and cause significant potassium loss, unlike potassium-sparing agents.

Diuretic Patient Teaching

Advise patients to take the medication in the morning, monitor daily weights, and watch for signs of electrolyte imbalance.

HMG-CoA Reductase Inhibitors ("Statins") Side Effects

Muscle pain/weakness (myopathy), potential for liver damage, and rhabdomyolysis.

Calcium Channel Blockers (CCBs) Indications

Used to treat hypertension, angina pectoris, and certain supraventricular arrhythmias.

CCB Cardiac Action

Relaxes vascular smooth muscle (vasodilation) and reduces the workload of the heart by slowing conduction.

Anti-Anginal Drug Classes

Nitrates, Beta-blockers, and Calcium Channel Blockers.

Endocardium

The innermost layer of the heart that lines the chambers and valves.

Myocardium

The middle, thickest layer of the heart composed of cardiac muscle tissue.

Epicardium

The outermost layer of the heart wall, also known as the visceral layer of the serous pericardium.

Nicotinic Acid (Niacin) Side Effect

Significant cutaneous flushing and pruritus (itching).

Angiotensin II Receptor Blockers (ARBs) Indications

Used primarily to treat hypertension and heart failure, especially in patients who cannot tolerate ACE inhibitors.

ARBs Mechanism of Action

Blocks the binding of Angiotensin II to its receptors, leading to vasodilation and reduced aldosterone secretion.

Antidiuretic Hormone (ADH)

A hormone produced by the hypothalamus that signals the kidneys to conserve water.

ADH Urinary Output Effect

Increases water reabsorption in the kidneys, thereby decreasing urinary output.

Myocardial Infarction (MI)

Commonly known as a heart attack; occurs when blood flow to the heart muscle is blocked, leading to tissue death.

Ischemia

A condition in which the blood flow (and thus oxygen) is restricted or reduced in a part of the body.

Necrosis

The death of most or all of the cells in an organ or tissue due to disease, injury, or failure of the blood supply.

Thrombolytics

Drugs used to dissolve pre-existing blood clots in emergency situations like acute MI or ischemic stroke.

Normal Blood Pressure Range

Typically considered to be less than $120/80\,mmHg$.

MI Interventions

Immediate treatments often include oxygen, aspirin, nitroglycerin, and morphine.

Primary Hypertension

High blood pressure that has no identifiable underlying cause; also known as essential hypertension.

Secondary Hypertension

High blood pressure caused by an underlying condition, such as kidney disease or endocrine disorders.

Hydralazine Mechanism of Action

A direct-acting vasodilator that relaxes arterial smooth muscle to lower blood pressure.

Hypotension

Abnormally low blood pressure, often defined as less than $90/60\,mmHg$.

Non-pharmac