Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
MICRO-K vs MICRO-K LS
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Potassium is the principal intracellular cation, essential for maintaining cellular tonicity, electrical neutrality, and enzymatic reactions. It modulates neuromuscular transmission, cardiac contractility, and acid-base balance.
Potassium supplement; replaces intracellular potassium, essential for nerve conduction, muscle contraction, and acid-base balance.
Treatment of hypokalemia,Prevention of hypokalemia in patients at risk (e.g., on diuretics, digitalis)
Hypokalemia prevention or treatment,Diuretic-induced hypokalemia,Digitalis intoxication
Oral: 20-40 m Eq (1-2 capsules) two to four times daily; maximum 100 m Eq/day. Each capsule contains 8 m Eq (600 mg) of potassium chloride in a wax matrix extended-release formulation.
10-20 m Eq (as potassium chloride) orally twice daily; maximum 100 m Eq/day.
Not applicable; potassium is an electrolyte with no true elimination half-life; whole-body turnover half-life is approximately 12-24 hours, clinically relevant for dosing intervals.
Not applicable (K+ is an electrolyte, not eliminated by first-order kinetics). Clinical context: Serum K+ decline follows redistribution and excretion with a half-life of ~2-4 hours after IV bolus.
Potassium ions are not metabolized; they are primarily excreted unchanged by the kidneys (90%), with minor losses via feces and sweat.
Not metabolized; excreted primarily via kidneys.
Renal: approximately 90% of absorbed potassium is excreted in urine; biliary/fecal: less than 10% eliminated via feces.
Renal: ~90% as KCl (proportional to intake). Biliary/fecal: <10%.
None; potassium is not significantly bound to plasma proteins.
None (K+ is free ion).
0.5-0.7 L/kg; total body water distribution; clinically indicates extensive intracellular uptake (98% intracellular).
0.35 L/kg (approximate total body water; distributes primarily in extracellular fluid).
Oral: approximately 80-90% for Micro-K (extended-release); absorption occurs in small intestine.
Oral: ~80-100% for microencapsulated KCl (MICRO-K), but can be incomplete due to slower release.
e GFR ≥60 m L/min: No adjustment. e GFR 30-59: Reduce dose by 25-50% and monitor potassium. e GFR 15-29: Reduce dose by 50-75% and monitor potassium. e GFR <15: Avoid use or use with extreme caution; maximum 20 m Eq/day with frequent monitoring.
GFR 50-90 m L/min: no adjustment. GFR 30-49 m L/min: reduce dose by 25-50%. GFR <30 m L/min: avoid use or reduce dose by 50-75% with close monitoring.
No specific dosing adjustments recommended for hepatic impairment. Monitor potassium levels as hepatic disease may affect potassium homeostasis.
Child-Pugh A: no adjustment. Child-Pugh B: reduce dose by 25-50%. Child-Pugh C: avoid use or reduce dose by 50%.
Oral: <1 year: 1-2 m Eq/kg/day divided 2-4 times. 1-18 years: 1-3 m Eq/kg/day divided 2-4 times; maximum 100 m Eq/day. Extended-release capsules not recommended for children unable to swallow whole capsules.
1-3 m Eq/kg/day orally in 2-4 divided doses; maximum 1 m Eq/kg per dose and 100 m Eq/day.
Start at low end of dosing range (20-40 m Eq/day) due to decreased renal function; maximum 100 m Eq/day. Monitor renal function and potassium levels closely.
Initiate at lower end of dosing range (10-20 m Eq/day); monitor renal function and serum potassium frequently; adjust based on renal function.
None
No black box warning.
Hyperkalemia risk, especially in patients with renal impairment, diabetes, or those receiving potassium-sparing diuretics, ACE inhibitors, or ARBs,Suspect gastrointestinal obstruction or perforation with slow-release formulations; caution in patients with severe GI disorders,Use with caution in patients with cardiac disease, particularly those on digoxin,Monitor serum potassium levels regularly
Risk of hyperkalemia especially in renal impairment,Use with caution in cardiac disease,GI irritation or ulceration with oral forms,Slow release formulations may cause GI lesions
Hyperkalemia (serum potassium >5.5 m Eq/L),Renal failure or severe renal impairment (e.g., oliguria, anuria),Addison's disease,Acute dehydration,Concomitant use with potassium-sparing diuretics (e.g., amiloride, spironolactone, triamterene),Concomitant use with eplerenone,Solid dosage forms in patients with delayed gastric emptying or esophageal compression
Hyperkalemia,Severe renal impairment,Untreated Addison's disease,Acute dehydration,Use of potassium-sparing diuretics
Avoid high-potassium foods (e.g., bananas, oranges, spinach, potatoes, tomatoes) and potassium-based salt substitutes. Consuming large amounts of these may increase risk of hyperkalemia.
Avoid excessive intake of potassium-rich foods (e.g., bananas, oranges, potatoes, spinach, avocados, dried fruits, salt substitutes containing potassium chloride). Do not take with alcohol as it may increase GI irritation. Grapefruit juice has no significant interaction, but large amounts of any food high in potassium should be avoided.
Potassium chloride (Micro-K) is not associated with major congenital malformations. Normal maternal serum potassium levels are required for fetal development. Hypokalemia or hyperkalemia may increase risks. No trimester-specific risks documented.
MICRO-K LS (potassium chloride) is not associated with teratogenicity. No fetal risks have been reported in any trimester. Use during pregnancy is considered safe when indicated.
Potassium is a normal constituent of breast milk. Supplemental potassium does not affect milk potassium content. M/P ratio not applicable. Use with caution if maternal renal function impaired.
Potassium is a normal component of breast milk. No adverse effects expected at maternal therapeutic doses. M/P ratio: not applicable (endogenous electrolyte).
No standard dose reduction required. Pharmacokinetic changes in pregnancy (increased GFR, blood volume) may increase potassium requirements or decrease serum levels; monitor and adjust dose to maintain normal serum potassium (3.5-5.0 m Eq/L).
No dose adjustment typically required. Maintain serum potassium within normal range. Monitor for hypokalemia or hyperkalemia as clinically indicated.
Micro-K (potassium chloride extended-release) is used to prevent and treat hypokalemia. Avoid use in severe renal impairment, metabolic acidosis, or conditions with high potassium levels. Slow-release formulations reduce GI irritation but may be contraindicated in patients with GI motility disorders. Do not crush or chew capsules; administer with food and a full glass of water. Monitor serum potassium and renal function regularly.
MICRO-K LS contains potassium chloride microencapsulated granules for sustained release. Avoid in patients with severe renal impairment (Cr Cl <30 m L/min), untreated Addison's disease, or hyperkalemia. Use with caution in patients with cardiac disease or concurrent use of ACE inhibitors, ARBs, or potassium-sparing diuretics. Do not crush or chew capsules; administer with a full glass of water to prevent GI mucosal damage. Monitor serum potassium regularly, especially in elderly and diabetic patients.
Take this medication with food and a full glass of water to reduce stomach upset.,Swallow the capsule whole; do not crush, chew, or open it.,Do not suddenly stop taking this medication without consulting your doctor.,Avoid salt substitutes or potassium-containing supplements unless approved by your doctor.,Seek immediate medical attention if you experience signs of high potassium levels: muscle weakness, irregular heartbeat, or tingling in hands/feet.
Take this medication exactly as prescribed, preferably with meals or a full glass of water.,Do not crush, chew, or break the capsules; swallow them whole.,Avoid foods high in potassium (e.g., bananas, oranges, tomatoes, salt substitutes) unless directed by your doctor.,Contact your doctor immediately if you experience muscle weakness, irregular heartbeat, numbness/tingling, or dark/tarry stools.,Store at room temperature away from moisture and heat.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about MICRO-K vs MICRO-K LS, answered by our medical review team.
MICRO-K is a Electrolyte Supplement (Potassium) that works by Potassium is the principal intracellular cation, essential for maintaining cellular tonicity, electrical neutrality, and enzymatic reactions. It modulates neuromuscular transmission, cardiac contractility, and acid-base balance.. MICRO-K LS is a Electrolyte Supplement (Potassium) that works by Potassium supplement; replaces intracellular potassium, essential for nerve conduction, muscle contraction, and acid-base balance.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between MICRO-K and MICRO-K LS depend on the specific clinical indication. These are both Electrolyte Supplement (Potassium) agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of MICRO-K is: Oral: 20-40 m Eq (1-2 capsules) two to four times daily; maximum 100 m Eq/day. Each capsule contains 8 m Eq (600 mg) of potassium chloride in a wax matrix extended-release formulation.. The standard adult dose of MICRO-K LS is: 10-20 m Eq (as potassium chloride) orally twice daily; maximum 100 m Eq/day.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between MICRO-K and MICRO-K LS in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. MICRO-K is classified as Category C. Potassium chloride (Micro-K) is not associated with major congenital malformations. Normal maternal serum potassium levels are required for fetal development. Hypokalemia or hyperk. MICRO-K LS is classified as Category C. MICRO-K LS (potassium chloride) is not associated with teratogenicity. No fetal risks have been reported in any trimester. Use during pregnancy is considered safe when indicated.. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.