What medication is given to a patient with hypokalemia (low potassium)?

Treatment of Hypokalemia

For a patient with low potassium (hypokalemia), give oral potassium chloride as the first-line medication, typically 20-60 mEq per day divided into multiple doses, with each individual dose not exceeding 20 mEq. 1, 2

Severity-Based Treatment Algorithm

Mild to Moderate Hypokalemia (K+ 2.5-3.5 mEq/L)

Oral potassium chloride is the preferred route when the patient has a functioning gastrointestinal tract and serum potassium is greater than 2.5 mEq/L. 3, 4

• Start with potassium chloride 20-40 mEq per day for prevention of hypokalemia 2
• Use 40-100 mEq per day for treatment of established potassium depletion 2
• Divide doses so that no more than 20 mEq is given at one time to minimize gastrointestinal irritation 2
• Always administer with meals and a full glass of water—never on an empty stomach 2
• Target serum potassium of 4.0-5.0 mEq/L, as both hypokalemia and hyperkalemia increase mortality risk, particularly in cardiac patients 1

Severe Hypokalemia (K+ ≤2.5 mEq/L) or Urgent Situations

Intravenous potassium chloride is indicated when serum potassium is 2.5 mEq/L or less, when ECG abnormalities are present, when severe neuromuscular symptoms exist, or when the gastrointestinal tract is non-functioning. 3, 4

• Maximum peripheral IV concentration: ≤40 mEq/L 1
• Maximum peripheral IV rate: 10-20 mEq/hour 1, 5
• Continuous cardiac monitoring is mandatory for severe hypokalemia due to arrhythmia risk 1, 5
• In diabetic ketoacidosis, add 20-30 mEq potassium per liter of IV fluid (preferably 2/3 KCl and 1/3 KPO4) once K+ falls below 5.5 mEq/L with adequate urine output 1

Critical Pre-Treatment Checks

Before administering any potassium, you must check and correct magnesium levels first—hypomagnesemia is the most common reason for refractory hypokalemia and must be corrected before potassium levels will normalize, with a target magnesium >0.6 mmol/L. 1

• Verify adequate urine output (≥0.5 mL/kg/hour) to confirm renal function before giving potassium 1
• Check renal function (creatinine, eGFR) as impaired kidney function dramatically increases hyperkalemia risk 1
• Review current medications: patients on ACE inhibitors or ARBs alone or with aldosterone antagonists frequently do not require routine potassium supplementation, and it may be harmful 1

Alternative Medication Strategies

Potassium-Sparing Diuretics (More Effective Than Chronic Oral Supplements)

For persistent diuretic-induced hypokalemia, adding a potassium-sparing diuretic is more effective than chronic oral potassium supplements, providing stable levels without peaks and troughs. 1

• Spironolactone 25-100 mg daily (first-line option) 1
• Amiloride 5-10 mg daily in 1-2 divided doses 1
• Triamterene 50-100 mg daily in 1-2 divided doses 1, 6
• Avoid in patients with eGFR <45 mL/min due to hyperkalemia risk 1
• Check potassium and creatinine 5-7 days after initiation, then every 5-7 days until stable 1

Monitoring Protocol

• Recheck potassium within 3-7 days after starting oral supplementation 1
• Continue monitoring every 1-2 weeks until values stabilize 1
• Then check at 3 months, then every 6 months thereafter 1
• More frequent monitoring required in patients with renal impairment, heart failure, diabetes, or on medications affecting potassium 1

Common Pitfalls to Avoid

• Never supplement potassium without checking magnesium first—this is the single most common reason for treatment failure 1
• Do not administer digoxin before correcting hypokalemia, as this significantly increases risk of life-threatening arrhythmias 1
• Avoid NSAIDs entirely during potassium replacement, as they worsen renal function and increase hyperkalemia risk 1
• Do not combine potassium supplements with potassium-sparing diuretics without specialist consultation due to severe hyperkalemia risk 1
• Thiazide and loop diuretics should be questioned or temporarily held if severe hypokalemia exists, as they further deplete potassium 1

Special Populations

Patients on Diuretics

Consider reducing or temporarily holding potassium-wasting diuretics if K+ <3.0 mEq/L, as this directly halts ongoing losses. 1, 6

Cardiac Patients

Maintain potassium strictly between 4.0-5.0 mEq/L in patients with heart failure or on digoxin, as both hypokalemia and hyperkalemia increase mortality. 1

Patients with Renal Impairment

Use extreme caution with potassium supplementation when eGFR <45 mL/min—start at low doses (10 mEq daily) and monitor within 48-72 hours. 1