Drugs for Angina and Heart Failure Flashcards
What is angina pectoris/angina?
Severe chest pain due to ischemia of the heart muscle
What is the incidence of angina in the US?
9 million Americans experience angina
What types of angina are there?
-Stable angina
-Unstable angina
-Variant/Prinzmetal angina
What is oxygen supply and demand?
The amount of oxygen that the heart needs and the amount of oxygen that is supplied to the heart
What is atherosclerosis?
Fatty plaques that can build up in the coronary arteries
What is coronary artery spasm?
A temporary tightening or spasm of the coronary arteries which can decrease blood flow
What conditions can lead to reduced oxygen delivery?
-Anemia
-Respiratory diseases
What is the pathogenesis of class angina due to atherosclerosis?
-In a patient with atherosclerosis, there is dilation of arterioles at rest to compensate for increased blood flow resistance from plaque
-During exercise, further dilation cannot occur which leads to myocardial ischemia and pain
What are the symptoms of stable angina?
-Usually occurs during physical exertion (stable)
-Usually lasts for short periods of time
-Relieved by rest or medicine
-May feel like chest pain that spreads to the arms, back, or other areas
What are risk factors for angina?
-Age (≥ 55 for men, ≥ 65 for women)
-Family history
-Cigarette smoking
-Physical inactivity
-Medications
-Chronic stress
-HTN
-Diabetes mellitus
-Kidney disease
-Obesity
-Dyslipidemia
What is stable angina?
-Most common form
-Effort induced angina
-Due to reduction in blood flow from atherosclerosis
-Symptoms are relieved by rest or nitroglycerin
What is unstable angina?
-Angina caused by blocking of the coronary arteries by blood clots
-Chest pain occurs with increased frequency
-Not relieved by rest of medication
-Requires hospital admission and more aggressive therapy
-Can lead to MI and death
What is Prinzmetal’s/Variant angina?
-Angina due to coronary artery spasm
-Attacks are unrelated to physical activity, HR, or blood pressure
-Responds to coronary vasodilators such as nitroglycerin and calcium-channel blockers
What are the classes of drugs that are used to treat angina?
-Non-selective β-blockers
-β-1 blockers (cardioselective)
-Calcium channel blockers
-Nitrates
-Sodium channel blockers
Which drugs increase the oxygen supply to the heart?
-β-blockers
-Nitrates
-Calcium channel blockers
Which drugs decrease the oxygen demand of the heart?
-β-blockers
-Calcium channel blockers
What drug is NOT effective in treating variant angina? Why?
-β-blockers
-They do not counteract vasospasm
What different organic nitrates are there that are used for the treatment of angina? What do they do?
-Nitroglycerin
-Isosorbide dinitrate
-Isosorbide mononitrate
-Cause a rapid reduction in myocardial oxygen demand
-Used for all types of angina
What is the mechanism of action of organic nitrates?
-Relax vascular smooth muscle by their intracellular conversion to nitric oxide, which increased guanylate cyclase and increases cyclic guanosine monophosphate (cGMP)
-Elevated cGMP leads to dephosphorylation of the myosin light chain
What are the two major effects of nitroglycerin?
-Dilation of large veins, which decreases preload/venous return to the heart which reduces work of the heart
-Dilates coronary vasculature which provides increased blood flow to the heart
What is the preferred method of administration for nitroglycerin and isosorbide dinitrate? Why?
-Sublingual
-Because sublingual has a much faster onset of action (1-3 min.) compared to oral administration (35 min.)
-There is a significant first-pass rate of nitroglycerin in the liver if given orally
What is the preferred method of administration for isosorbide mononitrate?
Oral extended release because it is more stable against liver breakdown and has longer duration of action
What are adverse effects of organic nitrates?
-Headache
-Orthostatic hypotension
-Facial flushing
-Reflex tachycardia
What drug is organic nitrates contraindicated with? Why?
Sildenafil (Viagra) to prevent dangerous hypotension
How are β-blockers used to treat angina?
-Decrease oxygen demands by lowering HR and force of contraction
-Decreases HR, contractility, CO, and BP
How are calcium channel blockers used to treat angina?
-Vasodilate arterioles to increase blood supply to heart by relaxing smooth muscle
-Decreasing contractility of the heart which reduced oxygen demand
What calcium channel blocker exerts a greater effect on the myocardium? Which exerts a greater effect on vascular smooth muscle?
-Verapamil: myocardium
-Nifedipine: vascular smooth muscle
What are adverse effects of calcium channel blockers?
-Constipation
-Reflex tachycardia
-Can worsen HF due to negative inotropic effects (only Verpamil and Diltiazem contraindicated with HF)
What is a common sodium channel blocker that is used to treat angina?
Ranolazine
What is the mechanism of action of sodium channel blockers for the treatment of angina?
Inhibits sodium channels which decreases intracellular sodium which decreases AP in heart muscle which decreases oxygen demand of the heart
What type of angina is sodium channel blockers indicated for?
Stable and chronic angina
What are common side effects of sodium channel blockers?
-Dizziness
-Headache
-Constipation
-QT interval prolongation
What are PT considerations for pt’s taking angina medications?
-BP monitoring
-Awareness of angina symptoms
-Exercise prescription
-Recognize side effects
-Patient education
