Cardiac Pharmacology: Nitro and Digoxin

Nitroglycerin (Nitro)

• Use: First-line agent for angina relief.
• Mechanism: Generalized vascular and coronary vasodilation.
• Side Effects: Headache, hypotension, dizziness, weakness, and faintness.
• Routes: Sublingual, topical (ointment/patch), buccal (extended-release tablet), oral (extended-release capsule/tablet), aerosol spray, and IV.

Digoxin (Lanoxin)

• Action: Positive inotropic (increases myocardial contractility), increasing stroke volume and blood flow. Negative chronotropic (decreases heart rate) and negative dromotropic (decreases heart cell conduction).
• Side Effects: Anorexia, nausea, vomiting, bradycardia, premature ventricular contractions (PVCs), cardiac dysrhythmias, headaches, malaise, blurred vision, visual illusions, and confusion/delirium.
• Toxicity (Overdose): Digoxin immune Fab (Digibind) is the antidote. It binds with digoxin forming excreted molecules in urine.
• Nursing Interventions: Monitor apical pulse rate (greater than 60 bpm). Monitor serum digoxin level (therapeutic level 0.5–2 ng/mL), and monitor serum potassium (K+) levels reporting any hypokalemia. Avoid antacids.

Antianginal Drugs

• Nitrates: Reduce venous tone, decrease workload of the heart, and promote vasodilation.
• Beta Blockers: Decrease workload and oxygen demands.
• Calcium Channel Blockers (CCBs): Decrease workload and oxygen demands.
• Effectiveness: Effective for variant (vasospastic) angina pectoris.

Calcium Channel Blockers

• Action: Block calcium levels, promote vasodilation. Relax coronary artery spasm (variant angina), relax peripheral arterioles (stable angina), and decrease cardiac oxygen demand, contractility, afterload, and peripheral resistance. Thus, reducing workload.
• Side Effects: Dizziness, flushing, headache, hypotension, reflex tachycardia, peripheral edema, fatigue, AV block, and bradycardia.
• Examples: Verapamil, Diltiazem, Amlodipine, Nifedipine, etc.

Amlodipine (Norvasc), Nifedipine (Procardia), Diltiazem (Cardizem)

• Related to Calcium Channel Blockers.

Angiotensin II Receptor Blockers (ARBs)

• Action: Prevent aldosterone release and block angiotensin II from its receptors, preventing the renin-angiotensin-aldosterone system.
• Examples: Valsartan (Diovan), Losartan (Cozaar).

ACE Inhibitors

• Action: Inhibit the formation of angiotensin II and blocks the release of aldosterone.
• Examples: Benazepril (Lotensin), Captopril (Capoten), etc.

Heparin

• Examples: Low-molecular-weight heparin (LMWH) such as enoxaparin sodium (Lovenox), dalteparin sodium (Fragmin), tinzaparin sodium (Innohep).
• Antidote: Protamine sulfate.

Warfarin (Coumadin)

• Action: Inhibits hepatic synthesis of vitamin K, affecting clotting factors II, VII, IX, and X.
• Use: Prevention of thromboembolic conditions like thrombophlebitis, pulmonary embolism, and stroke.
• Monitoring: Monitor prothrombin time (PT) and international normalized ratio (INR).
• Antidote: Vitamin K.

Aspirin

• Use: Prevention of myocardial infarction (MI), thromboembolism, and stroke.
• Long-Term Use: Low-dose therapy.
• Mechanism: Inhibits cyclooxygenase, needed by platelets to synthesize thromboxane A.

Clopidogrel, Rivaroxaban

• Use: Antiplatelet, prevention of cardiovascular events.
• Use: Anticoagulant, prevention of blood clots.

Thrombolytic Drugs

• Action: Convert plasminogen to plasmin to dissolve clots.
• Examples: Alteplase (Activase), Streptokinase, etc.

Statins

• Action: Inhibit HMG-CoA reductase, thus reducing cholesterol biosynthesis.
• Examples: Atorvastatin (Lipitor), Fluvastatin (Lescol), Lovastatin (Mevacor), Pravastatin (Pravachol), Rosuvastatin (Crestor), Simvastatin (Zocor).
• Side Effects: Liver impairment, rhabdomyolysis (skeletal muscle disorder), Cataracts.
• Nursing Interventions: Monitor liver enzymes. Report unexplained muscle tenderness, weakness, fever, or malaise. Teach patients the importance of taking the medication as prescribed.

Metoclopramide

• Classification: Antiemetic.
• Action: Suppresses impulses to the CTZ (chemoreceptor trigger zone).

Ondansetron (Zofran)

• Classification: Serotonin antagonists, Antiemetic.
• Action: Blocks serotonin receptors in the CTZ and vagal nerve terminals in the upper GI tract.

Bisacodyl

• Classification: Stimulant laxative.
• Action: Increases peristalsis by irritating the intestinal mucosa.

Sucralfate

• Classification: Pepsin inhibitor.
• Action: Forms a protective paste that covers ulcers and prevents acid and pepsin damage.

Lactulose

• Classification: Osmotic laxative.
• Action: Draws water into the colon increasing bulk and stimulating peristalsis.

Aluminum Hydroxide

• Classification: Antacid.
• Side Effect: Constipation.

Polyethylene Glycol (PEG)

• Classification: Osmotic laxative.
• Use: Bowel preparation for surgery or diagnostic procedures.

Treatments for Helicobacter Pylori

• Examples: Omeprazole, and Clarithromycin

Insulin

• Types: Rapid-, Intermediate-, Long-acting.
• Examples: Lispro (Humalog), Aspart (NovoLog), etc.
• Classification: Combination. Short- & intermediate-acting, Rapid- & Intermediate-acting.

Metformin

• Classification: Non-sulfonylureas.
• Action: Decreases hepatic glucose production, diminishes postprandial hyperglycemia, blunts intestinal glucose absorption.

Glipizide

• Classification: Second Generation Sulfonylurea.
• Action: Stimulates pancreatic beta cells to secrete more insulin and increases tissue response to insulin.

Glucagon

• Classification: Hyperglycemic hormone
• Action: Increases blood sugar by stimulating glycogenolysis.
• Use: Used to treat insulin-induced hypoglycemia.
• Route: Parenteral (subcutaneous, intramuscular, intravenous).