Angina and antianginal drugs

Angina (angina pectoris)

• It is a characteristic sudden, severe, pressing chest pain radiating to the neck, jaw, back and arms.
• It is caused by insufficient coronary blood flow to the myocardium that leads to less oxygen supply and ischemia.
• This imbalance between oxygen delivery and utilization may result during exertion from a spasm of the vascular smooth muscles or from obstruction of blood vessels caused by atherosclerosis.

Types of Angina pectoris

1. Stable or typical angina
2. Unstable angina
3. Prinzmetal or varient angina

Stable or typical angina

• it is most common form of angina
• characterized by burning, heavy or squeezing feeling of chest
• it is caused by reduced coronary perfusion due to coronary atherosclerosis
• heart becomes vulnerable to ischemia whenever there is increased demand of cardiac workload by physical activity, emotional excitement or any other cause
• it is relief by rest or nitroglycerin (vasodilator)

Unstable angina

• it lies between stable angina and myocardial infarction
• it occurs with progressively increasing frequency and is precipitated with less effort
• it is unrelated to exercise and occurs at rest
• it requires more aggressive therapy such as treatment of dyslipidemia, hypertension, or diabetes, to retard progression to myocardial infarction
• it is not relief by rest or nitroglycerin

Prinzmetal or varient angina

• uncommon pattern of episodic angina
• occurs at rest due to coronary artery spasm
• patients may have significant coronary atherosclerosis
• anginal attacks are unrelated to physical activity, heart rate, or blood pressure
• it is responds promptly to nitroglycerin and calcium channel blockers

Antianginal drugs or agents

Antianginal drugs is a term used to describe a wide variety of medicines that are used in the management of angina. Angina is a heart condition characterized by a narrowing of the coronary arteries (the arteries of the heart). Chest pain is its main symptom.

1. Nitrates (eg, isosorbide dinitrate, isosorbide mononitrate, nitroglycerin):

• These relax smooth muscle within the blood vessels, widening them and making it easier for blood and oxygen to reach the heart

2. Calcium channel antagonists (eg, diltiazem, nifedipine, nimodipine, verapamil):

• These inhibit calcium transfer into cells thereby inhibiting contraction of vascular smooth muscle

3. Beta blockers (eg, atenolol, pindolol, propranolol, metoprolol):

• These drugs slow the heart, reducing how hard it has to work

Ranolazine. The exact way it exerts its antianginal effect is not known but may be through inhibition of ion channels during cardiac repolarization.