Exam 3- Cardiovascular Drugs Flashcards
What would be the best choice of Beta blockers based on pharmacokinetics?
–One with a long enough half-life to permit once daily dosing
–Consistent bioavailability
–Limited CNS penetration
–An excretion mechanism that does not require dosage adjustments
Combined alpha and beta blockers
Carvedilol (Coreg), labetolol (Normodyne)
•The alpha1 and beta blockade decreases blood pressure and peripheral resistance by peripheral vasodilation
–Standing BP is more affected than supine
ACEIs (-pril)
Effective for all types and stages of HTN
•Their action on the renin-angiotensin-aldosterone system (RAAS) makes them popular drugs
Elevate bradykinin which causes cough.
ARBs (-sartan)
- Same indications as ACEIs
- Several are pro drugs
- Do not elevate levels of bradykinin → therefore, incidence of cough is rare
CCBs
Dihydropyridines – amlodipiine, felodipine, isradipine, nifedipine
•Nondihydropyridines – diltiazem, verapamil
•Used as first line therapy – especially in black patients and patients with ischemic heart disease
•Also used in older adults with isolated systolic hypertension
Alpha 1 blockers
•Block postsynaptic alpha1 receptors in the vasculature resulting in a decrease in both arterial and venous vasoconstriction
•Also relax bladder neck and prostate gland
•Side effects – significant orthostatic
Ex: Doxazosin (Cardura), prazosin (Minipress), terazosin (Hytrin)
Central Alpha2 agonists
•Stimulate alpha2 receptors in the brainstem which decreases sympathetic stimulation to the heart and PVS
–Reduces BP and pulse; also decreases renin production in kidneys
•Not used as monotherapy – side effects
Ex: Clonidine (Catapres), methyldopa (Aldomet)
Direct-acting peripheral vasodilators (PVDs)
•Act by direct relaxation and dilation of arteriolar smooth muscle – decreasing PVR
•Used for severe HTN
•Side effects – rebound HTN, dizziness
Ex: Hydralazine (Apresoline), minoxidil (Loniten)
Antilipidemic drugs
Types: HMG-CoA Reductase Inhibitors •Cholesterol Absorption Inhibitor •Bile Acid Resins •Fibric Acid Derivatives •Niacin •Omega 3 and Omega 6 Fatty Acids
Statins
Block HMG-CoA reductase, an enzyme required in the initial step in cholesterol synthesis
Lowers LDL
•Adverse effects – small elevations in LFTs, myopathy
Cholesterol absorption inhibitors
Ezetimibe (Zetia) zebra entering studio with diarrhea
- blocks absorption of cholesterol.
- Used as adjunct to diet and statin in reducing total cholesterol, LDL, and TG levels, and increasing HDL levels
•Side effects - Diarrhea
Bile acid resins
Block intestinal reabsorption of bile. Used to lower LDL levels when triglycerides are well-controlled.
Can increase triglycerides, N/V, gallstones.
Cholestyramine (Questran), Colesevelam (WelChol)
Fibric Acid Derivatives
- Fenofibrate (Tricor), gemfibrozil (Lopid)
- Act by increasing lipolysis of triglycerides by lipoprotein lipase
- Used for treatment of high triglycerides.
Niacin
Inhibits VLDL secretion → decreases production of LDL
–Reduces TG, total cholesterol, LDL levels; increases HDL levels
•Side effects – intense flushing and pruritis, N/V, diarrhea
Omega-3 and Omega-6 Fatty Acids
- (Lovaza), Fish oil
- Reduce TG by inhibiting VLDL and apo-B-100 synthesis; also decrease postprandial lipemia
- Side effects – interfere with coagulation at high doses, GI upset
Nitrates
•Used for immediate relief of acute angina, and prevention of anginal attacks
•Reduce afterload and preload
–Preload reduction is most important
•Nitroglycerin has short half-life
•Adverse reactions – orthostatic hypotension, syncope, headache
Beta Blockers
•Reduce oxygen requirements of myocardium by preventing stimulation of SNS receptors
–Reduces contractility
–Decreases sinus node rate
–Decreases atrioventricular conduction velocity
•Side effects – hypotension, bradycardia, bronchospasm
Calcium Channel Blockers
All CCBs relax arterial smooth muscle, but have little effect on venous beds
–Significant reduction in afterload with limited effect on preload
•Act via two types of receptors
–Dihydropyridine
–Nondihydorpyridine
•The two classes of CCBs have different effects on AV nodal conduction
Use of CCBs in Angina
- Nifedipine (Procardia), amlodipine (Norvasc), felodipine (Plendil)
- Considerable variation in oral absorption
- Highly protein bound
- Side effects – headache, dizziness, hypotension
Class I Antiarrhythmics
- Sodium channel blockers
* Similar in structure and action to local anesthetics
Class IA antiarrhythmics
- Block fast Na channels → slows action potential depolarization
- Also block PNS discharge → increased conduction rate at the AV node
- Side effects – N/V, increased heart rate, widened QRS complex, prolongation of PR and QT intervals
- Procainamide, quinidine
Class IB Antiarrhythmics
- Lidocaine
- Block both activated and inactivated Na channels
- Most effective in treating acute ventricular arrhythmias associated with MI, cardiac surgery and catheterization, cardioversion, and digoxin toxicity
Extensive first-pass metabolism •Widely distributed through the body –Concentrated in adipose tissue –Crosses blood-brain barrier •Adverse effects – drowsiness, confusion, CV depression