Cardiovascular drugs Flashcards
Drug Classes:
- Inotropic drugs
- Anti-arrhythmic drugs
- Anti-anginal drugs
- Anti-hypertensive drugs
- Anti-lipenic drugs
INOTROPIC DRUGS:
- Positive inotropic effect =
- Negative chronotropic effect =
- Negative dromotropic effect =
- Increase the force of heart muscles
- Slow heart rate
- Slow electrical impulse conduction through atrioventricular (AV) node
INOTROPIC DRUGS:
Digoxin:
Treats heart failure:
Treats Supra-ventricular arrhythmias:
Note: cardiac glycosides have narrow therapeutic index (margin of safety)
- a cardiac glycodside derived from foxglove plant (digitalis)
- Used to treat heart failure bc strengthens contraction of ventricles by boosting intracellular calcium at cell membrane, enabling stronger heart contractions.
- Used to treat supra-ventricular arrhythmias (arterial fibrillation, atrial flutter) as acts on CNS to slow heart rate; also increases refractory period (period when cells of conduction system can’t conduct impulse)
ANTI- ARRHYTHMIC DRUGS
Used to treat:
Unfortunately:
4 Classes:
-Class I:
IA
IB
IC
- Class II:
- Class III:
- Class IV:
- treat arrhythmias, disturbances of normal heart rhythm
- unfortunately can worsen or cause arrhythmias
I sodium channel blockers
IAlters myocardial cell membrane [quinidine, procainamide]
IBlocks influx of sodium ions [lidocain, mexiletine]
I slows Conduction [moricizine, propafenone, flecainide]
-II: beta-adrenergic antagonists or beta-adrenergic blockers on heart conductions system; reduces electrical impulse [propranolol, esmolo]
-III: for life-threatening arrhythmias [amiodarone]
IV: calcium channel blockers [ verapamil, diltiazem]
How Lidocaine works:
Ischemic mycardial cells allow rapid infusion of sdium ions➡depolarization increased ➡ ventricular arrhythmias result
Lidocaine slows infusion of sodium ions in ischemic myocardial cells….depolarization prolonged……SA node keeps control of cardiac rhythm.
ANTI-ANGINAL DRUGS
Treat angina by:
3 Classes:
- Nitrates
- Beta-adrenergic blockers
-calcium channel blockers:
-by reducing myocardial oxygen demand, by increasing amount of oxygen to heart, or both
- Nitrates: acute angina [amyl nitrite, nitroglycerin]
- Beta blockers: long-term angina prevention [atenolol, propranolol]
- Calcium channel blockers: when other drugs fail to prevent angina [verapamil, amlopidine]
ANTI-ANGINAL DRUGS
Angina:
Increased:
-coronary arteries supply insufficient oxygen to myocardium, causing increased:
- Heart rate
- Preload: blood volume in ventricle at end of diastole
- Afterload: pressure in arteries leading from ventricle
- Force of myocardial contractility
ANTI-ANGINAL DRUGS
Afterload decrease by:
Heart rate decreased by:
Preload decreased by:
Contractility decreased by:
-calcium channel blockers, nitrates
- beta-adrenergic blockers, some calcium channel blockers
- nitrates
-beta-adrenergic blockers, calcium channel blockers
ANTI-ANGINAL DRUGS:
Nitrates are given:
They cause:
Adverse effects:
- given sublingually, chewable tablet, lingual aerosol, inhalation as absorbed almost completely across mucous membranes
- cause smooth muscle in veins to dilate….less blood to heart…less blood volume in ventricles before contraction (preload)….reduced oxygen requirement.
-Adverse effects: 3 H’s (headache, hypotension, increased heart rate)
ANTI-ANGINAL DRUGS
Beta-blockers decreas:
Adverse effects:
- decrease blood pressure, block eta-adrenergic receptor sites in heart muscle and conduction system….decreased heart rate, decreased force of contraction, lower oxygen demand
- bradycardia, angina, fainting, fluid retention, peripheral edema, shock, heart failure, arrhythmias.
ANTI-ANGINAL DRUGS
Calcium channel blockers increase:
No calcium =
Coronary arteries dilate which decreases _______ to increase myocardial _____supply
Adverse effects:
-myocardial oxygen supply, slow heart rate by blocking slow calcium channels
=dilation
Afterload, oxygen
-cardiovascular reactions
ANTI-HYPERTENSIVE DRUGS:
Classes:
-Sympatholytic drugs:
- Vasodilating drugs:
- ACE inhibitors:
- Angiotenisin II receptor blockers (ARBs):
Reduce blood pressure (systolic, diastolic, or both)
- inhibit/block sympathetic nervous system….dilation of peripheral blood vessels or decreased cardiac output [clonidine, carvedilol, labetalol]
- work directly on arteries/veins [diazoxide, hytralazine], or are calcium channel blockers preventing contraction of vascular smooth muscle
- interrupt renin-anginotensin-aldosterone system [captopril, enalapril, lisinopril, ramiprill]
- block vasoconstrictive effects of angiotensin II [losartan, valsartan, olmesartan]
ANTI-HYPERTENSIVE DRUGS
Adverse effects
- Direct vasodilators produce adverse effects related to reflex activation of sympathetic nervous system
- blood pressure falls sympathetic nervous system stimulated…produce compensatory measures (vasoconstriction, tachycardia)
ANTI-LIPEMIC DRUGS:
-Lowers:
5 classes:
-Bile-sequestering:
-Fibric acid derivatives:
HMG-CoA reductase inhibitors (statins):
- Nicotinic acid:
- Cholesterol absorption inhibitors:
- Lower blood lipids (cholesterol, triglycerides, phospholipids), decreasing risk of coronary artery disease (CAD)
- bind bile acids/salts in small intestine…complex excreted in feces [cholestyramine, colestipol]
- from fungi; dicrease triglycerides [fenofibrate, gemfibronzil]
- decrease lipids by interfering with cholesterol synthesis [atorvastin, lovastatin, simvastatin]
- decrease triglycerides, apolipoprotein B, HDL [niacin]
-inhibit cholesterol absorption from intestine [ezetimbie]
ANTI-LIPEMIC
Bile-sequestering drugs
remain in GI tract where bind bile acids (used to emulsify flood lipids) in small intestine…..form insoluble complex….excreted in stool
Decrease bile acids in gall bladder trigger liver to make more from stored cholesterol
Adverse Effect: reduce absorption of lipid-soluble vitamins (A, D, E, K); long-term therapy can result in fecal impaction, vomiting, diarrhea, hemorrhoids
