Angina pectoris

Angina pectoris, commonly known as angina, is severe chest pain due to ischemia (a lack of blood, thus a lack of oxygen supply) of the heart muscle, generally due to obstruction or spasm of the coronary arteries (the heart's blood vessels). Coronary artery disease, the main cause of angina, is due to atherosclerosis of the cardiac arteries. The term derives from the Latinangina ("infection of the throat").

There is a weak relationship between severity of pain and degree of oxygen deprivation in the heart muscle (i.e., there can be severe pain with little or no risk of a heart attack, and a heart attack can occur without pain).

Angina pectoris, the primary symptom of ischemic heart disease, occurs when myocardial oxygen demands exceed the oxygen supply. Pharmacological agents used to treat angina balance the supply and demand of oxygen by either reducing the oxygen demand, increasing the oxygen supply to the heart, or both.



NITRATES :


The principle action of nitrates is relaxation of vascular smooth muscle, producing dilation of peripheral arteries and veins, especially the latter. Dilation of the veins promotes peripheral pooling of blood and decreases venous return to the heart, thereby reducing left ventricular end-diastolic pressure and preload. Arteriolar relaxation reduces systemic vascular resistance, and systolic arterial pressure and afterload. Dilation of coronary arteries also occurs.

Rapid-acting Nitrates:


Rapid-acting nitrates relieve acute angina. They may also be used prophylactically in situations likely to provoke an attack.


Isordil Sublingual, Nitrolingual, Nitrostat


Long-acting Nitrates:
Long-acting nitrates can be used for long-term management of chronic stable angina.
Oral: Dilatrate-SR, Imdur, Ismo, Isordil Titradose, MonoketTopical: Minitran, Nitro-BID, Nitro-DUR


BETA-BLOCKERS 
By blocking the positive chronotropic and inotropic effects of catecholamines and by decreasing blood pressure, beta-blockers (eg, Corgard, Inderal, Lopressor, Tenormin, Toprol-XL) generally reduce the oxygen requirements of the heart, making them useful for patients in the long-term management of angina pectoris.


CALCIUM CHANNEL BLOCKERS
By inhibiting the entry of calcium into vascular smooth muscle and cardiac muscle, calcium channel blockers (eg, Caduet, Calan, Cardene, Cardizem, Covera-HS, Dilacor XR, Norvasc, Procardia, Tiazac) promote dilation of the coronary and peripheral arteries. As a result they decrease coronary vascular resistance and increase coronary blood flow. Negative inotropic and chronotropic effects of the heart may also be produced. All of these actions can reduce angina symptoms. These agents are considered to be the drugs of choice for vasospastic (Prinzmetal) angina.

Calcium channel blockers are commonly used in combination with beta-blockers.



OTHER ANTIANGINALS                                                  


Ranolazine (Ranexa) is indicated for use in chronic angina alone or in combination with amlodipine, beta-blockers or nitrates when other antianginal drugs have not had an adequate response. It has antianginal and anti-ischemic effects which are not dependant on reductions in heart rate or blood pressure. It's mechanism of action is unknown.