Summary
Highlights
Nurse Mike introduces the pharmacology of heart failure, covering essential medications like ACE inhibitors, ARBs, beta-blockers, digoxin, and diuretics. The primary goal of these medications is to drain fluid and improve the heart's pumping efficiency. A core Enclelex tip is that most of these drugs lower blood pressure and require slow position changes, except for digoxin, which affects heart rate but not blood pressure.
ACE inhibitors (ending in 'prill') and ARBs (ending in 'sartan') are discussed. Both lower blood pressure but not heart rate. ACE inhibitors are a first choice, while ARBs are a second alternative. They work by blocking the RAAS system, which can lead to high potassium levels (hyperkalemia). Important side effects for ACE inhibitors (ACE) include avoiding in pregnant patients, angioedema (swelling of the face and tongue, a deadly airway risk), and a nagging cough. ARBs (sartans) spare potassium and do not cause cough or angioedema. Patients should avoid potassium-rich foods. Early signs of hyperkalemia include muscle spasms, peak T-waves, and ST elevations on an ECG. Always monitor cardiac activity with any potassium imbalance. The 'three A's' for these drugs—antihypertensive, avoid in pregnancy, and adds potassium—are crucial.
Beta-blockers (ending in 'lol') act as 'brakes' for the heart, causing 'double lows': low heart rate and low blood pressure. They are negative inotropes, chronotropes, and dromotropes, meaning they decrease force, time, and speed of conduction, reducing cardiac output. Beta-blockers block beta-1 receptors in the heart and beta-2 receptors in the lungs, leading to potential bronchospasms, making them contraindicated in patients with asthma or COPD. Key side effects are the 'four B's': bradycardia and low blood pressure (hold if HR < 60 or SBP < 90/100), breathing problems (bronchospasm), 'bad for heart failure' (can worsen acute heart failure, look for new edema, crackles, weight gain, JVD), and blood sugar masking in diabetics (monitor closely as they can hide symptoms of hypoglycemia).
Calcium channel blockers (ending in 'dipine', 'zem', 'mil') calm the heart by dropping both blood pressure and heart rate. They block calcium movement, relaxing vascular smooth muscles, decreasing resistance, and taking strain off the heart. Similar to beta-blockers, they have negative chronotropic, inotropic, and dromotropic effects. Key nursing considerations (CCB) include checking heart rate and blood pressure before administration (hold if SBP < 90/100 or HR < 60), teaching slow position changes to prevent orthostatic hypotension, and noting that bad headaches are a normal side effect. Avoid rapid IV drips to prevent significant blood pressure drops.
Digoxin is a positive inotropic drug, increasing the force of heart contractions ('digs for a deeper contraction'), primarily used for systolic heart failure. It also decreases heart rate (negative chronotropic) but does not affect blood pressure. Digoxin is highly toxic; hence, the mnemonic 'digoxin is a toxin'. The 'ATP' memory trick covers key considerations: Apical pulse (check for a full 60 seconds; hold if HR < 60), Toxicity (over 2.0; early signs include vision changes like fuzziness, blurred vision, color changes, difficulty reading, nausea, vomiting, anorexia, dizziness; notify HCP immediately), and Potassium (low potassium below 3.5 increases toxicity risk; digoxin itself does not cause hypokalemia, unlike diuretics). Elderly patients with decreased kidney function are at higher risk for toxicity; creatinine levels over 1.3 indicate kidney injury.
Vasodilators like nitroglycerin ('nitro') dilate blood vessels, decreasing blood pressure and reducing preload and afterload, which improves oxygen delivery to the heart. Common vasodilators include nitroglycerin, nitroprusside, hydralazine, isosorbide (note 'O' for vasodilator, not a diuretic), and minoxidil. A critical precaution is to never administer with 'Viagra' drugs (ending in 'afil') due to the risk of extremely low blood pressure. Stop nitroglycerin if systolic BP is below 90/100 or drops by 30 points. Normal side effects ('three H's') include headaches, hypotension (orthostatic hypotension), and hot flushing. Teach slow position changes due to dizziness.
Diuretics 'drain' fluid from the body, decreasing blood pressure and are the primary treatment for acute or worsening heart failure. There are two main types: potassium-wasting (loop diuretics like furosemide/torsemide and thiazide diuretics like hydrochlorothiazide) and potassium-sparing (spironolactone). Potassium-wasting diuretics are first-line for acute heart failure, working by blocking sodium reabsorption in the kidneys. These are only given if potassium is normal (3.5-5.0); patients should eat potassium-rich foods and avoid licorice root. Potassium-sparing diuretics like spironolactone 'spare' potassium by blocking aldosterone, requiring avoidance of potassium-rich foods. For any potassium abnormality, a cardiac monitor is the first nursing action. Hypokalemia causes flat T-waves and ST depression (and U-waves), while hyperkalemia causes peak T-waves and ST elevation. IV potassium replacement must be given slowly (over an hour or more, typically 4 hours), never as an IV push.
Killer nursing considerations for diuretics include checking BP (hold if SBP < 100), BUN and creatinine (kidney labs, over 1.3 indicates injury), and potassium imbalances (monitor cardiac function, muscle spasms, cramps, weakness, paresthesias). Five general Enclelex tips for diuretics: take in the morning, slow position changes for dizziness, daily weights (report 2-3 lbs gain), risk for sunburn (use sunblock), and maintain a low-sodium diet (avoid chips, fried foods, canned/packaged foods, fast food, and OTC meds high in sodium like NSAIDs and antacids). Furosemide, if given too fast, can be ototoxic (ear pain, tinnitus) and cause hypotension (not bradycardia). Long-term use can lead to nephrotoxicity (high BUN/creatinine) and hypokalemia.