Chapter 15: Cardiovascular Pharmacology

Cardiovascular pharmacology encompasses a diverse array of medications designed to manage heart disease, hypertension, dysrhythmias, and related vascular conditions through distinct molecular mechanisms. Adrenergic agents, including sympathomimetics and alpha-selective agonists, modulate autonomic signaling to influence blood pressure and cardiac output, though sympathomimetics risk tachycardia and dysrhythmias while centrally acting agents require careful discontinuation to prevent rebound hypertension. Beta-adrenergic antagonists reduce cardiac workload and heart rate, serving as foundational therapy for angina, post-myocardial infarction recovery, and heart failure, but demand gradual dose reduction to avoid acute complications. Inotropic agents such as cardiac glycosides and phosphodiesterase inhibitors strengthen cardiac contraction through calcium-mediated mechanisms, with digoxin requiring vigilant monitoring due to its narrow therapeutic window and susceptibility to toxicity from electrolyte disturbances. Antidysrhythmic medications, categorized into four classes based on ion channel effects, suppress irregular electrical activity but carry inherent risk of pro-dysrhythmia. Vasodilators including nitrates and direct-acting agents reduce cardiac oxygen demand and afterload, though tolerance to nitrates necessitates scheduled drug-free periods. Calcium channel blockers inhibit L-type channels to produce vascular relaxation and reduced contractility across multiple cardiac indications. Renin-angiotensin-aldosterone modulators, particularly angiotensin-converting enzyme inhibitors and angiotensin II receptor antagonists, represent cornerstone therapies for heart failure and blood pressure management by suppressing a critical hormonal system, with notable adverse effects and strict pregnancy contraindications. Diuretics decrease intravascular volume through altered renal sodium handling, demanding careful electrolyte monitoring. Anticoagulants, antithrombotic agents, and thrombolytics address clot formation and dissolution through distinct pharmacological targets, with thrombolytics reserved for acute ischemic emergencies due to hemorrhage risk. Antihyperlipidemic agents, led by statins that inhibit hepatic cholesterol synthesis, reduce cardiovascular event risk through lipid modification, though muscle toxicity and hepatic dysfunction require patient awareness and monitoring.