K-Dur - Drug Monograph

Introduction

K-Dur is a potassium chloride extended-release preparation used for the treatment and prevention of hypokalemia. As a critical electrolyte supplement, it plays an essential role in maintaining proper cellular function, nerve transmission, and muscle contraction throughout the body.

Mechanism of Action

Potassium is the principal intracellular cation in most body tissues. K-Dur works by providing supplemental potassium ions that help maintain intracellular tonicity, transmit nerve impulses, contract cardiac and skeletal muscles, maintain normal renal function, and regulate acid-base balance. The extended-release formulation is designed to minimize the potential for high local concentrations of potassium chloride in the gastrointestinal tract.

Indications

• Treatment of hypokalemia with or without metabolic alkalosis
• Prevention of hypokalemia in patients who would be at risk if hypokalemia were to develop (e.g., patients taking digitalis or diuretics)
• Management of hypokalemia associated with diabetic ketoacidosis

Dosage and Administration

• Usually administered in divided doses (2-4 times daily)
• Should be taken with meals and with a full glass of water

• Geriatric: Start with lower doses due to potential renal impairment
• Renal impairment: Use with caution; dosage adjustment required based on GFR
• Pediatric: Safety and effectiveness not established

Pharmacokinetics

Contraindications

• Hyperkalemia
• Conditions in which potassium excretion is impaired (renal failure, Addison's disease)
• Solid oral dosage forms in patients with esophageal compression or delayed gastric emptying
• Hypersensitivity to any component of the formulation
• Concomitant use with potassium-sparing diuretics

Warnings and Precautions

• GI effects: May cause serious GI adverse effects including bleeding, ulceration, and perforation
• Hyperkalemia: Can occur with overdosage or in patients with impaired potassium excretion
• Renal function: Must be monitored regularly
• Metabolic acidosis: May require additional bicarbonate therapy
• Cardiac effects: Rapid IV administration can cause fatal hyperkalemia

Drug Interactions

• Potassium-sparing diuretics (spironolactone, triamterene, amiloride): Increased risk of hyperkalemia
• ACE inhibitors/ARBs: Increased potassium retention
• NSAIDs: May reduce renal potassium excretion
• Digoxin: Hypokalemia may increase digitalis toxicity; hyperkalemia may decrease effectiveness
• Heparin: May cause hyperkalemia

Adverse Effects

• Nausea
• Vomiting
• Abdominal discomfort
• Diarrhea

• Hyperkalemia (muscle weakness, paralysis, cardiac arrhythmias)
• GI ulceration, bleeding, or perforation
• Esophageal stricture formation
• Cardiac arrest (with severe hyperkalemia)

Monitoring Parameters

• Serum potassium levels (baseline, during dosage adjustment, and periodically during maintenance)
• Renal function (BUN, creatinine, GFR)
• ECG (in patients at risk for hyperkalemia or with cardiac disease)
• Acid-base status
• Signs and symptoms of GI irritation
• Digitalis levels if concomitant therapy

Patient Education

• Take with food and a full glass of water
• Do not crush, chew, or break tablets
• Report any difficulty swallowing, abdominal pain, or GI discomfort immediately
• Recognize symptoms of hyperkalemia (muscle weakness, irregular heartbeat)
• Do not use salt substitutes without medical supervision
• Keep regular follow-up appointments for monitoring
• Store at room temperature away from moisture

References

1. FDA Prescribing Information: K-Dur (potassium chloride extended-release) 2. Gennari FJ. Hypokalemia. N Engl J Med. 1998;339(7):451-458. 3. Hollander-Rodriguez JC, Calvert JF Jr. Hyperkalemia. Am Fam Physician. 2006;73(2):283-290. 4. Package Insert: K-Dur® (potassium chloride extended-release tablets) 5. American Association of Clinical Endocrinologists medical guidelines for clinical practice for the evaluation and treatment of hyperthyroidism and hypothyroidism. Endocr Pract. 2002;8(6):457-467. 6. KDIGO Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int Suppl. 2013;3(1):1-150.