Cardiovascular Drugs Made EZ: Part 1

Pharmacology is a key subject when studying for any healthcare board exam, such as the NCLEX or USMLE. This word can be a simple stimulus for nightmares in many in nursing or medical school studying for their boards. We are going to take a multi-part look at this subject by looking at one of the biggest classes of drugs that you will need to know: Drugs effecting the heart and vasculature.


This is a huge class of drugs, accounting for a huge chunk of the drugs that we actually need to know well, and is one that the NCLEX and USMLE are going to ask you about. Lets break this class down into smaller, more manageable chunks. We will start with drugs used to treat Hypertension, as this class is very large and very important. First of all, take a look at the picture below for a summary of the drugs we will discuss.

ACE Inhibitors

Names:
• “Prils” Think an ACE is a Pro (kinda like a pril)
• Examples: Enalapril (Vasotec), Captopril, Lisinopril
Uses:
• Hypertension, Heart Failure, Protection for diabetics vs nephropathy, Decrease Mortality in post-MI patients due to afterload reduction
Action:
• blocks the enzyme that converts angio I to angio II in the lungs. Angio II leads to vasoconstriction, aldosterone release, and sodium retention: this is blocked, which decreases blood pressure and puts less strain on heart
Common Side Effects:
• Dry hacking cough; Angioedema; Hyperkalemia
• Taste disturbance; Rash; Insomnia, Orthostasis
Nursing Implications:
• CI: Pregnancy Category D; Bilateral Renal Stenosis
• Use K supplements carefully due to hyperkalemia concerns
• Stop drug if cough, angioedema
• Taste of food may be diminished during first month of therapy

Angiotensin Receptor Blockers (ARBs)

Names:
• “Sartans”
• Examples: Losartan (Cozaar), Irbesartan, Valsartan (Diovan)
Uses:
• Hypertension, Heart Failure
Action:
• Blocks the receptor for Angiotensin II, blocking the effects of this potent vasoconstrictor
Common Side Effects:
• Hyperkalemia, Angioedema, Orthostatic hypotension
Nursing Implications:
• CI: Pregnancy Category D in 2nd/3rd trimesters; Bilateral Renal Stenosis
• Safer side effect profile than ACE inhibitors but less studied

To understand ACE and ARB it is vital that you have an idea of what the Renin-Angiotensin-Aldosterone System (RAAS) is. Remember the purpose of RAAS is to increase blood pressure in response to decreased renal blood flow or pressure, and the purpose of the drugs that work here is to block this system and lower blood pressure. Check out the pick below for a summary of the RAAS and where certain drugs work.

Beta Blockers (or beta antagonists)

Names:
• “OlOls: Remember Beta video tapes? They are OLdOLd
• Ex: Selective B1: Metoprolol, Atenolol (I MET A TEN last night)
• Ex: B1B2: Propanolol (Inderal), Labetalol, Carvedilol (Coreg) (ilol, alol-also alpha blocker)
Uses:
• Hypertension, Angina, Arrhythmias, Glaucoma, MI prophy, Migraines
Action:
• Block adrenergic Beta receptors (1 heart, 2 lungs), leading to lower sympathetic activity = decrease in cardiac output, blood pressure and renin activity. Also some drugs lower aqueous humor production
Common Side Effects:
• Bradycardia, fatigue, insomnia, bizzare dreams, sex dysfunction, lipid dysfunction; Respiratory distress (wheezing), Agranulocytosis, depression
Nursing Implications:
• C/I in asthma, bradycardia, severe renal/hepatic disease, hyperthyroid, CVA
• Signs of hypoglycemia (DM), tachycardia (hyperthyroid) may be masked
• Glucagon may reverse overdose

Calcium Channel Blockers (Antagonists)

Names:
• Dihydropyridines: “Pines”: Amlodipine (Norvasc), Nifedipine (Procardia)
• Non-Dihydropines: Diltiazem (Cardizem), Verapamil
Uses:
• Angina, Arrhythmias (Non-D’s have more AV node effect)
• Hypertension (Dihydro’s have more vasodilation effect)
• HT (Pines), Dysrhythmias (Verapamil), HT/Dys (Diltiazem)
Action:
• Blockade of Ca channels causes arteries to relax (vasodilate) and cardiac conduction to slow through the AV node
Common Side Effects:
• All: H/A, hypotension, dizziness, peripheral edema, Renal/Hepatic dysfunction
• Dihydros: Ankle edema, flushing, tachycardia, gingival hyperplasia
• Non-D’s: AV block, bradycardia, worsened systolic dysfunction
Nursing Implications:
• Use very cautiously with heart failure/left ventricle inpairment, AV block
• Don’t abruptly stop medication; Warn patient to contact MD if irregular HR, SOB, swelling, pronounced dizziness, constipation, nausea, hypotension

Peripheral Alpha Blockers

Names:
• Mixed names: “Zosins” for BPH, “ilol” for HT;
• Examples: Carvedilol (Coreg), Tamulosin (Flomax), Prazosin (Minipress)
Uses:
• Hypertension, Peripheral Vascular Dz (raynaulds, phlebitis, etc), BPH
Action:
• Blockade of Alpha 1 relaxes smooth muscle in arteries and prostate capsule, leading to lower blood pressure, reduction in BPH, and increased blood in tissues (warm/pink skin) as well as Renal arteries
Common Side Effects:
• Orthostatic Hypotension (especially first dose), Reflex Tachycardia, Ejaculation problems, nasal congestion
Nursing Implications:
• Begin with small dose and give at bedtime to avoid dizziness and syncope
• Change positions slowly to decrease orthostatic hypotension
• Alcohol, Excessive exercise, prolonged standing, heat make S/E worse

Central Alpha Blockers

Names:
• Clonidine (Catapres); Methyldopa (Aldomet)
Uses:
• Hypertension
Action:
• Central acting sympatholytic stimulates pre-synaptic alpha receptors to release NE, which paradoxically reduces peripheral NE release, inhibiting vasoconstriction = vasodilation and lower BP
Common Side Effects:
• Sodium/Water retention, Dry mouth, Bradycardia, Impotence, Depression
Nursing Implications:
• Advise patient not to abruptly withdrawal because significant rebound hypertension can result
• C/I in impaired liver function so monitor liver function tests occasionally
• Do not confuse with the benzo Klonipin (patients have done so and taken a bunch of Clonidine for a high, only to end up with a real low…BP that is.


Diuretics

Types:
• Loop: Furosemide (Lasix), Bumetanide (Bumex), Torsemide (Demadex)
• Thiazide: Hydrochlorothiazide (HCTZ)
• K-sparing: Amiloride, Spironolactone
• Carbonic Anhydrase Inhibitors: Acetazolamide (Diamox)
Uses: Edema associated with heart failure; Ascites with Cirrhosis; Hypertension
Action:
• Loop: Inhibit Na, Cl, and H2O resorption in the loop of henle thus decreasing blood volume; Also increase the excretion of K; Potent diuretics
• Administer IV Lasix slowly because hearing loss can occur if given rapidly
• Thiazide: Inhibit Na resorption and increase Cl, H2O, K, Ca, Bicarb, Mg excretion in the urine; Also cause arterial dilatation; Moderate diuretic
• While K and Na may be excreted, HyperCa is more likely to develop so never administer to patient with hypercalcemia;
• Eat foods rich in potassium, use sunscreen, and change position slowly
• Caution when taking with Lithium, Digoxin, Corts, PO Diabetic meds
• K-sparing: Block Na-K exchange in distal tubule causing loss of Na and water and retention of K; Weak diuretic mostly added to preserve K
• C/I in severe renal/hepatic dysfunction, hyperkalemia, Current ACE-I use
• Carbonic anhydrase inhibitors:
• Used to treat M.Alkalosis, Open Angle Glaucoma, Epilepsy, High altitude sickness
• Inhibits the enzyme carbonic anhydrase which normally is responsible for excreting H to combine with HCO3 for elimination of excess acidity, as well as promoting diuresis. This drug obviously leads to an increase level of H+ in the blood (M.Acidosis) and an increased excretion of Bicarb (HCO3)
• C/I with CLOSED (narrow) angle Glaucoma
• S/E i/c Renal Calculi, Hypercalcemia, and Hemolytic anemia
Common Side Effects:
• Loop/Thiazides: Hypokalemia, Hyperuricemia, Glucose intolerance, sexual dysfunction, increase cholesterol/triglyceride levels
• K-Sparing: Hyperkalemia especially when used with ACE inhibitors
Nursing Implications:
• Caution for electrolyte disturbances; Watch for cramping, paresthesia
• Administer in morning to avoid diuresis during night, Supplements (PhosLo)