Anti-Anginal Drugs

Vocabulary practice flashcards covering pathophysiology, mechanisms, adverse effects, and algorithmic therapies for anti-anginal medications based on lecture notes.

Atherosclerosis in Angina

The development of coronary artery lesions that obstruct blood flow, resulting in an imbalance between myocardial oxygen supply and demand that manifests as stable angina or acute coronary syndrome.

Typical Angina Pectoris

A condition characterized by sudden, severe, crushing chest pain that may radiate to the neck, jaw, back, and arms, often accompanied by dyspnea, nausea, vomiting, indigestion, or diaphoresis.

Classes of Stable Angina Medications

The four main pharmacological classes used alone or in combination: $\beta$-blockers, calcium channel blockers, organic nitrates, and the sodium channel–blocking agent ranolazine.

Mechanism of Action of Organic Nitrates

Intracellular conversion into nitrite ions and subsequently nitric oxide, which activates guanylate cyclase to increase cyclic guanosine monophosphate ($\text{cGMP}$), leading to dephosphorylation of myosin light chains and vascular smooth muscle relaxation.

Hemodynamic Effects of Nitrates

Dilation of large veins to reduce preload and cardiac workload, alongside dilation of coronary vasculature to increase blood supply to the myocardium.

Sublingual Nitroglycerin

The preferred initial drug formulation for prompt relief of an acute anginal attack induced by exercise or emotional stress, effective within $2\text{ min}$ and avoiding hepatic first-pass metabolism.

Isosorbide Mononitrate

An organic nitrate possessing enhanced oral bioavailability and an extended duration of action ($\ge 12\text{--}24\text{ hr}$) owing to its stability against hepatic breakdown.

Isosorbide Dinitrate

An oral organic nitrate that undergoes hepatic denitration into two biologically active mononitrates that exert antianginal actions.

Nitrate Adverse Effects

Commonly includes headache, as well as postural hypotension, facial flushing, and reflex tachycardia at elevated doses.

Nitrate and PDE-5 Inhibitor Interaction

A strictly contraindicated combination with phosphodiesterase type $5$ inhibitors (such as sildenafil) that potentiates nitrate vasodilatory actions and precipitates severe, life-threatening hypotension.

Nitrate Tolerance

A rapid loss of vascular responsiveness to nitrate-induced vasodilation, resolved by providing a daily $10\text{ to }12\text{ hour}$ nitrate-free interval (typically during the night).

$\beta$-Adrenergic Blockers

First-line antianginal agents that antagonize $\beta_1$ receptors to reduce heart rate, myocardial contractility, cardiac output, and arterial blood pressure, thereby diminishing myocardial oxygen demand at rest and during exercise.

Cardioselective $\beta$-Blockers (Metoprolol and Atenolol)

The preferred $\beta_1$-selective agents for angina management, chosen over nonselective prototypes such as propranolol.

$\beta$-Blocker Discontinuation Protocol

Gradual dose titration downward over $2\text{ to }3\text{ weeks}$ to prevent severe rebound angina, myocardial infarction, and hypertension.

Calcium Influx in Myocardial Ischemia

Depolarization induced by tissue hypoxia that accelerates calcium entry into myocytes, driving adenosine triphosphate ($\text{ATP}$)–consuming enzymes and exhausting energy reserves.

Amlodipine

An oral dihydropyridine calcium channel blocker that acts primarily as an arteriolar vasodilator with minimal impact on cardiac conduction; particularly beneficial for variant angina provoked by coronary spasm.

Verapamil

A nondihydropyridine calcium channel blocker that decreases heart rate, oxygen demand, and atrioventricular ($\text{AV}$) conduction velocity, exhibiting greater negative inotropic effects than amlodipine but weaker vasodilatory actions.

Diltiazem

A nondihydropyridine calcium channel blocker that reduces sinus node discharge rate, slows atrioventricular ($\text{AV}$) conduction, and promotes coronary artery vasodilation.

Ranolazine

A sodium channel blocker that selectively inhibits the late sodium current ($\text{late } I_{\text{Na}}$), dampening intracellular sodium and calcium overload to improve myocardial diastolic relaxation and oxygen balance.

Stepwise Management Algorithm for Stable Angina

A clinical treatment sequence beginning with sublingual nitroglycerin for acute symptom control, followed by initiation of a $\beta$-blocker, addition of a calcium channel blocker or long-acting nitrate if symptoms persist, and subsequent escalation to ranolazine.