Cardiovascular Pharmacology and Electrolyte Management

Posted on Mar 23, 2026 in Medicine & Health

Electrolyte Imbalances

Potassium (K+)

  • Hypokalemia (< 3.5): GI losses (N/V/D), dehydration, diuretic use, laxative abuse. Digoxin + hypokalemia = high toxicity risk. S/S: Arrhythmias (PVC to V-fib), muscle weakness, paresthesia, fatigue. ECG: Flat T, prominent U, low ST. Treat: PO/IV K+ supplements, K+-rich foods (OJ, banana, potato, spinach). NI: Monitor K+ with diuretics; IV rate < 10 mEq/h.
  • Hyperkalemia (> 5): Renal disease, ACEI/ARBs, K+-sparing diuretics. S/S: Arrhythmias (PVC to V-fib), paresthesia, cramps. ECG: Peaked T, flat P, long PR, wide QRS. Treat: Kayexalate (PO/rectal), IV Insulin/Dextrose, IV NaBicarb/Ca+. NI: Monitor renal function and K+ levels.

Sodium (Na+)

  • Hyponatremia (< 135): GI losses, diuretics, laxatives. S/S: GI (anorexia, cramping), CNS (lethargy, seizures). Treat: PO Na+, Isotonic fluids (NS), hypertonic fluids. NI: Monitor for fluid overload (crackles, edema).
  • Hypernatremia (> 145): Fluid loss (sweat/urine), tube feeds, steroids, Cushing’s. S/S: Restlessness, lethargy, thirst, dry membranes, HTN, edema. Treat: PO H2O, IV D5W or hypotonic (0.45% NaCl). NI: Monitor Na+ levels, avoid high-Na foods.

Magnesium (Mg+)

  • Hypomagnesemia (< 1.5): Diuretics, alcoholism, CAD/HF, post-CABG. S/S: Arrhythmias (PVC to V-fib), seizures, tetany, tremors. Treat: PO/IV Mg+ supplement. NI: Give slowly; monitor for seizures.
  • Hypermagnesemia (> 2.5): Renal disease, excessive intake. S/S: Nausea, flushing, lethargy, bradycardia, hypotension. Treat: Prevent in renal failure; IV Isotonic (0.9% NS) + loop diuretic; dialysis. NI: Avoid Mg-containing meds (antacids).

Diuretic Therapy

Types and Mechanisms

  • Loop Diuretics: Furosemide, bumetanide, torsemide. Use: HF, fluid overload, HTN. SE: Hyponatremia, dehydration, hypotension, ototoxicity, hypokalemia. NI: Monitor BP/K+/Cr; take in morning.
  • Thiazides: Hydrochlorothiazide (HCTZ), metolazone. Use: HTN, HF. SE: Hyponatremia, dehydration, hypotension, hypokalemia, hyperglycemia. NI: Monitor K+; monitor blood sugar.
  • K+-Sparing: Spironolactone. Use: Adjunct for HF/HTN. SE: Hyperkalemia, hypotension. NI: Monitor BP/K+; avoid ACEI/ARB/renal failure.
  • Osmotic Diuretics: Mannitol. Use: ↓ ICP and cerebral edema. NI: Inspect for crystals; use filter tubing.

Hypertension and RAAS

Management

  • Essential HTN: Idiopathic.
  • Secondary HTN: Known cause (renal, endocrine).
  • RAAS Regulation: Angiotensin II causes vasoconstriction; Aldosterone causes Na+/water retention.
  • Drug Classes: ACE Inhibitors (-pril), ARBs (-sartan), CCBs (Amlodipine).

Heart Failure (HF)

Pathophysiology and Treatment

  • Diagnostic: EF (normal 55-70%), CXR (fluid), BNP (cardiac status).
  • Management: ACEI/ARB/ARNI, Beta-blockers, Diuretics, Digitalis.
  • Evaluation: Monitor daily weight, edema, dyspnea, JVD, activity tolerance.

Angina and ACS

Treatment

  • Angina: Organic nitrates (Nitroglycerin), CCBs (Diltiazem), Beta-blockers.
  • ACS: Morphine, Oxygen, Nitroglycerin, Aspirin (MONA).
  • Reperfusion: PCI (stent) or Fibrinolytics (tPA).

Anticoagulants and Antiplatelets

  • Antiplatelets: Aspirin (ASA), Clopidogrel (Plavix).
  • Anticoagulants: Warfarin (monitor INR 2-3), Heparin (monitor aPTT), LMWH (Enoxaparin), DOACs (Apixaban, Rivaroxaban).
  • NI: Monitor for bleeding, avoid invasive procedures, use soft-bristle toothbrush.

Dysrhythmias

Management

  • Supraventricular: Afib/Aflutter. Treat: Cardioversion or Amiodarone.
  • Ventricular: PVCs, V-tach, V-fib. Treat: CPR, Defibrillation, Epinephrine, Amiodarone, Lidocaine.
  • Key Drugs: Adenosine (SVT), Atropine (Bradycardia).