Antianginal Drugs Flashcards
how do we treat angina
problem: reduced oxygen supply
increased oxygen demand
treatment -increase oxygen delivery coronary vasodilators decreased oxygen demand -vasodilators(reduce preload and afterload)
-Beta blockers(reduce HR and contractility)
drugs for angina
nitrates/nitrites
beta-adrenergic receptor blockers
calcium channel blockers
nitrates/nitrites action
cause vasodilation because of relaxation of smooth muscles
potent dilating effect on coronary arteries
used for prevention and treatment of angina
vasodilation results in reduced myocardial oxygen demand nitrates cause dilation of both large and small coronary vessels
Result: oxygen to ischemic myocardial tissue
Nitrates alleviates coronary artery spasms
Nitroglygerin
prototypical nitrate
large first-pass effect with oral forms
used for symptomatic treatment of ischemic heart conditions(angina)
IV form is used for blood pressure control in perioperative hypertension, treatment of HF, ischemic pain, pulmonary edema associated with acute MI and hypertensive emergencies
examples of nitrates
amyl nitrate(rapid acting) inhalation
Nitroglycerine
isorbide dinitrate
isorbide mononitrate
used for: acute relief of angina
prophylaxis in situations that may provoke angina
long-term prophylaxis of angina
adverse drug reactions of nitrates
orthostatic hypertension and syncope
headaches
tachycardia
contraindications for nitrates
known allergy severe anemia closed angle glaucoma hypotension head injury contraindicated with the use of drugs for erectile dysfunction
Beta blockers actions
beta 1 receptors are located in the hearts conduction system and throughout the myocardium
when beta receptors are blocked by beta blockers, the rate at which the pacemaker SA node fires decreases and the time it takes for the node to recover increases(negative chromotropic effect)
-these effects reduce oxygen demand, which helps in the treatment of angina by reducing the workload of the heart
beta-blockers/examples
non-selective beta blockers
-propranolol, nadolol, timolol
cardioselective beta blockers
-atenolol, metoprolol, penbutolol
beta blockers mechanism of action
blcok beta 1 receptors on the heart
decrease HR, resulting in decreased myocardial oxygen demand and increased oxygen delivery to the heart
decrease myocardial contractility, helping to conserve energy or decrease demand
after an MI: high level of circulating catecholamines irritate the heart, causing an imbalance in supply and demand ratio and even leading to life-threatening dysrhythmias
beta blockers block the harmful effeects of catecholamines, thus improving survival after an MI
Beta-blockers/indications
- angina
- antihypertensive
- cardiac dysrhythmias
- cardioprotective effects, especially after an MI
- some used for migraine headaches, essential trmors, and stage fright
beta-blockers/adverse effects
cardiovascular: bradycardia, hypotension, second or third degree heart block, heart failure,
metabolic: altered glucose and lipid metabolism
CNS: dizziness, fatigue, mental depression, lethargy, drowsiness, unusual dreams
impotence, wheezing, dyspnea
contraindications of beta-blockers
bradycardia severe heart failure cardiogenic shock asthma relative contraindication with clients with diabetes
beta-blockers interactions
when combined with antihypertensives and diuretics: may cause hypotensions
when combined with calcium channel blockers may cause hypotension, bradycardia, and heart block
when combined with insulin and oral hypoglycemia agents may mask the signs of hypoglycemia
calcium channel blockers action
causes coronary artery vasodilation causes peripheral arterial vasodilation decreasing systemic vascular resistance reduces the workload of the heart resulting in decreased myocardial oxygen demand
limited or no effect on other smooth muscles and skeletal muscles they do not adversely affect lipid and glucose metabolism
an overdose would be treated by using IV calcium solutions and positive inotropes
