Introduction
Potassium chloride is an essential mineral supplement and medication used to prevent and treat hypokalemia (low blood potassium levels). As the primary intracellular cation in the body, potassium plays a critical role in numerous physiological processes including nerve conduction, muscle contraction, and cardiac function. Potassium chloride is available in various formulations including oral solutions, tablets, capsules, and intravenous preparations.
Mechanism of Action
Potassium is the major intracellular cation in the body, with normal serum concentrations maintained between 3.5-5.0 mEq/L. Potassium chloride works by directly supplementing potassium ions, which are essential for:
- Maintaining resting membrane potential and electrical excitability of cells
- Regulating cardiac rhythm and contractility
- Facilitating neuromuscular transmission
- Supporting normal cellular metabolism and enzyme function
- Regulating acid-base balance and osmotic pressure
Indications
FDA-Approved Indications:- Treatment and prevention of hypokalemia
- Management of digitalis intoxication
- Prevention of hypokalemia in patients taking diuretics
- Management of hypokalemic periodic paralysis
- Adjunctive therapy in metabolic alkalosis
- Prevention of hypokalemia during insulin therapy for diabetic ketoacidosis
Dosage and Administration
Oral Administration:- Adults: 20-100 mEq/day in divided doses (typically 2-4 times daily)
- Maximum single dose: 20-40 mEq
- Maximum daily dose: 200 mEq (under close monitoring)
- Concentration should not exceed 40 mEq/L via peripheral line or 80 mEq/L via central line
- Maximum infusion rate: 10 mEq/hour via peripheral line, 20-40 mEq/hour via central line (with cardiac monitoring)
- Must be diluted in appropriate IV fluids
- Renal impairment: Dose adjustment required based on GFR and serum potassium levels
- Elderly: Start with lower doses due to decreased renal function
- Pediatrics: 2-3 mEq/kg/day in divided doses
Pharmacokinetics
Absorption: Rapidly absorbed from the gastrointestinal tract (approximately 90% bioavailability) Distribution: Primarily intracellular (98% of total body potassium); serum levels represent only 2% of total body potassium Metabolism: Not metabolized; functions as an electrolyte Elimination: Primarily renal excretion (90%), with small amounts excreted in feces and sweat Half-life: Variable, dependent on renal function and acid-base statusContraindications
- Hyperkalemia (serum potassium >5.0 mEq/L)
- Severe renal impairment with oliguria or azotemia
- untreated Addison's disease
- Acute dehydration
- Heat cramps
- History of hypersensitivity to potassium chloride
- Conditions with delayed gastrointestinal transit
Warnings and Precautions
Black Box Warning:- Potassium chloride tablets have been associated with serious gastrointestinal lesions including bleeding, ulceration, and perforation
- Cardiac monitoring required for IV administration >10 mEq/hour
- Risk of hyperkalemia, particularly in patients with renal impairment
- Use caution in patients with cardiac disease
- Monitor acid-base status
- Avoid rapid IV administration (can cause cardiac arrest)
- Use caution in patients taking medications that affect potassium excretion
Drug Interactions
Significant Interactions:- ACE inhibitors/ARBs: Increased risk of hyperkalemia
- Potassium-sparing diuretics: Increased risk of hyperkalemia (spironolactone, triamterene, amiloride)
- NSAIDs: May decrease potassium excretion
- Heparin: May cause hyperkalemia
- Digoxin: Hypokalemia may increase digoxin toxicity; hyperkalemia may decrease effectiveness
- Beta-blockers: May impair potassium shifting into cells
Adverse Effects
Common:- Nausea, vomiting, abdominal discomfort
- Diarrhea
- Gastrointestinal irritation
- Hyperkalemia (muscle weakness, paresthesia, confusion, cardiac arrhythmias)
- Gastrointestinal bleeding, ulceration, or perforation
- Cardiac arrest (with rapid IV administration)
- Phlebitis at IV site
Monitoring Parameters
- Serum potassium levels (before and during therapy)
- ECG (for patients receiving IV potassium or with known cardiac disease)
- Renal function (BUN, creatinine)
- Acid-base status
- Signs of gastrointestinal irritation
- Fluid status
- Magnesium levels (hypomagnesemia can cause refractory hypokalemia)
Patient Education
- Take with food or immediately after meals to minimize gastrointestinal upset
- Do not crush, chew, or suck tablets (unless specifically designed for this)
- Report signs of hyperkalemia: muscle weakness, irregular heartbeat, confusion
- Report severe abdominal pain, vomiting, or bloody stools
- Do not use salt substitutes without medical supervision
- Maintain adequate hydration
- Follow prescribed dosing schedule carefully
- Be aware of potassium-rich foods (bananas, oranges, potatoes, tomatoes)
References
1. Hollander-Rodriguez JC, Calvert JF. Hyperkalemia. Am Fam Physician. 2006;73(2):283-290. 2. Gennari FJ. Hypokalemia. N Engl J Med. 1998;339(7):451-458. 3. FDA. Potassium Chloride Extended-Release Tablets Label. 2021. 4. Mount DB. Disorders of potassium balance. In: Brenner and Rector's The Kidney. 11th ed. Elsevier; 2020. 5. Palmer BF, Clegg DJ. Physiology and pathophysiology of potassium homeostasis. Adv Physiol Educ. 2016;40(4):480-490. 6. Kardalas E, et al. Hypokalemia: a clinical update. Endocr Connect. 2018;7(4):R135-R146. 7. American Association of Clinical Endocrinologists. Medical guidelines for clinical practice for the evaluation and treatment of hyperkalemia. Endocr Pract. 2016;22(Suppl 3):1-20.