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Cardiac Drugs/Diuretics
• Digoxin (Lanoxin) – positive inotrope (increases force of contraction); negative chronotrope (decreases heart rate). How do you assess for this? (Always take AP for a full minute!)
• Client with long hx of daily digoxin and furosemide (Lasix) use; creates a high risk for dig toxicity (Lasix can cause hypokalemia, which can lead to dig toxicity)
• Digoxin taken with dronedarone (Multaq), which is another antidysrhythmics, can significantly increase blood levels of digoxin and further increase the effects.
• Digoxin toxicity – know normal digoxin level (0.5 – 2 ng/mL); serum potassium (K+) level (3.5 to 5.0 mEq/L); low potassium or magnesium levels may increase risk for digoxin toxicity; S/S of dig toxicity
include anorexia, bradycardia, headache, dizziness, confusion, nausea, and visual disturbances (blurred vision, yellow vision, and/or halo vision); hold digoxin if AP less than 60.
• Calcium channel blockers (-dipine; amlodipine [Norvasc], nifedipine [Procardia]) – produce vasodilation and reflex tachycardia (↓BP and ↑HR). Verapamil and diltiazem produce vasodilation and cardiosuppression (↓BP and ↓HR).
• Beta blockers (atenolol, propranolol, esmolol, etc.) – remember beta1 and beta2 receptors (if not cardioselective, will also block beta2 receptors on the lungs) so be aware of any respiratory conditions such as asthma, emphysema, COPD, etc. Always check AP and BP before giving beta blocker. Do not give if HR
below 60. Never stop abruptly! Must taper. May cause angina or even an MI.
• Labetalol (beta blocker) for HTN: Notify prescriber for low pulse rate and do not give med; SE is weight gain (fluid retention) – pulmonary assessment (which is…). Remember monitoring weight is one of the best indicators of fluid gain or loss – 1 kg (2.2 lb) = 1,000 mL fluid gain or loss in 24 hrs.
• Pt. in CCU/ICU on nitro drip; becomes hypotensive, titrate (decrease rate of) nitro drip (is it OK to give nitroglycerin to a patient who is hypertensive? YES!!!)
• Furosemide (Lasix) – loop diuretic; rapid acting; used for rapid diuresis in emergencies (pulmonary edema); may produce hypokalemia (assess for muscle cramps, muscle weakness). Hypotension, F/E abnormalities, dehydration. SE: dizziness, HA, tinnitus, N/V/D, ↓ K+, hyperglycemia, ototoxicity with aminoglycosides
(-mycin drugs).
• May need potassium supplement. Foods containing potassium: dried fruits, fish, leafy veggies, squash, beans, meats, nuts, bananas, potatoes, dairy products.
• IV potassium (KCl) – assess overall condition of the veins. Use large vein, like antecubital (AC) vein when administering potassium. Venous access is important because IV potassium can irritate the vein. Have patient notify nurse immediately if burning at site. IV K+ extravasation can cause necrosis of tissues.
Don’t give IV push. ALWAYS DILUTED. Infuse at a rate no greater than 10 mEq/hr for peripheral IV and 20 mEq/hr for central line. Always use infusion pump. Assess IV site every hour.
• Antihypertensives and low potassium (K+); hypokalemia. Antihypertensive effects are more pronounced in the elderly. Which antihypertensives will raise potassium?
• Sodium polystyrene sulfonate (Kayexalate) – administered via NG tube or as enema to reduce serum potassium levels when potassium levels are at life-threatening values. To correct severe hyperkalemia, IV administration of dextrose and insulin, sodium bicarbonate, and calcium gluconate or chloride is often
required, followed by orally or rectally administered Kayexalate or even hemodialysis to eliminate the extra potassium from the body. Therapeutic range of K+ 3.5-5.0 mEq/L.
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