Logo

OpiCalc

FavoritesSpecialtiesDrugsGuidelinesMost Used

Quick Access

Favorites
Most Used

All Specialties

OpiCalc Logo
Clinical CalculatorsDrugsGuidelines
SpecsDrugsGuides
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
OpiCalc Logo

OpiCalc

Easy, fast, and private medical tools for clinicians. Always free.

No Login Required
Ready for the Bedside

Resources

About UsEditorial PolicyMedical DisclaimerPrivacy PolicyTerms of UseCookie Policy

Support

Contact Us

Clinical Notice:OpiCalc is not a substitute for professional clinical judgment. Always verify dosages and guidelines.

OpiCalc © 2018-2026

•

All Rights Reserved

Registry Hub
Electrolyte Replenisher/Prescription

POTASSIUM CHLORIDE 40MEQ

POTASSIUM CHLORIDE 40MEQ

Clinical safety rating

caution

Comprehensive clinical and safety monograph for POTASSIUM CHLORIDE 40MEQ (POTASSIUM CHLORIDE 40MEQ).


Mechanism of Action

Potassium is the major intracellular cation. It is essential for the maintenance of intracellular tonicity, transmission of nerve impulses, contraction of cardiac, skeletal, and smooth muscle, and maintenance of normal renal function. Replacement therapy corrects hypokalemia.

What the body does with it

MetabolismNot metabolized; primarily excreted unchanged by the kidneys with minor fecal elimination.
ExcretionRenal: >90% of potassium is excreted by the kidneys. Approximately 80-90% of an oral dose is eliminated in urine, with the remainder in feces via intestinal secretion.
Half-lifePotassium has no defined elimination half-life as it is a major intracellular ion tightly regulated by homeostatic mechanisms; serum levels reflect distribution and renal function. In anephric patients, the effective half-life is extended significantly.
Protein bindingPotassium is minimally protein-bound (<5%), with no specific binding proteins.
Volume of DistributionApproximately 0.5-0.7 L/kg for total body potassium; distributes primarily into intracellular fluid, with only about 2% in extracellular fluid. Clinical meaning: Vd is large due to extensive cellular uptake.
BioavailabilityOral: Approximately 90% for immediate-release formulations; sustained-release formulations have slightly lower bioavailability due to incomplete release. IV: 100%.
Onset of ActionOral: 30-60 minutes for serum potassium elevation; IV: immediate (within minutes) when given as an infusion.
Duration of ActionOral: 4-6 hours for sustained-release formulations; IV: Duration depends on infusion rate and renal function, typically 1-3 hours after stopping infusion.
Molecular Weight74.551

Classification & Brands

Dosing & administration

40 mEq orally once daily or divided every 6-12 hours; IV infusion at a rate not exceeding 10 mEq/hour with a maximum concentration of 40 mEq/L via peripheral line.

Dosage formINJECTABLE
Renal impairmentGFR 10-50 mL/min: administer 50% of standard dose; GFR <10 mL/min: avoid potassium chloride or use with extreme caution, close monitoring required.
Liver impairmentNo specific adjustment per Child-Pugh class; use with caution due to potential electrolyte imbalances, especially in cirrhosis.
Pediatric use0.5-1 mEq/kg/dose orally or IV, maximum 40 mEq/dose; IV rate not exceeding 0.5-1 mEq/kg/hour.
Geriatric useStart at lower end of dosing range (e.g., 20 mEq/day) due to age-related decline in renal function; monitor serum potassium closely.

Use during pregnancy

1st trimesterPotassium chloride is generally considered safe in pregnancy when used at recommended doses for the treatment or prevention of hypokalemia. Normal potassium levels are essential for maternal and fetal physiology.
2nd trimesterSimilar to T1, potassium chloride is used as needed for potassium repletion. No increased risk of fetal harm has been reported with appropriate use.
3rd trimesterPotassium chloride can be used in the third trimester if indicated. Monitoring of serum potassium is recommended to avoid hyperkalemia, particularly in women with pregnancy-induced hypertension or renal impairment.

Clinical note

Comprehensive clinical and safety monograph for POTASSIUM CHLORIDE 40MEQ (POTASSIUM CHLORIDE 40MEQ).

Placental transferPotassium readily crosses the placenta via active transport and diffusion; fetal serum potassium levels are maintained within a narrow physiologic range. Excessive maternal potassium can lead to fetal hyperkalemia.
BreastfeedingPotassium chloride is a normal constituent of breast milk and is considered compatible with breastfeeding. Maternal supplementation at recommended doses does not pose a risk to the nursing infant. However, monitor maternal potassium levels to avoid hyperkalemia.
Lactation RatingL1 (Compatible)
Teratogenic RiskFirst trimester: No evidence of teratogenicity in human studies; potassium chloride is a physiologic ion not associated with structural anomalies. Second trimester: No known fetal risks; maintains maternal-fetal electrolyte balance. Third trimester: Use is safe; intravenous administration may be necessary for maternal hypokalemia; adverse fetal effects only if maternal toxicity occurs (e.g., hyperkalemia).
Fetal MonitoringMonitor serum potassium levels, renal function, ECG (if hyperkalemia risk), and fluid balance. In pregnancy, assess maternal blood pressure and fetal heart rate during intravenous infusion to avoid volume overload.
Fertility EffectsNo known effect on human fertility. Animal studies do not indicate reproductive toxicity at therapeutic doses.

Warnings & precautions

■ FDA Black Box Warning

Potassium chloride injection concentrate must be diluted before use. Undiluted administration can cause cardiac arrest, fatal arrhythmias, or sudden death.

Side Effect Profile

Serious Effects

Absolute Contraindications

HyperkalemiaSevere renal impairment with oliguria or anuriaUntreated Addison's diseaseAcute dehydrationHeat crampsConcurrent use of potassium-sparing diuretics (e.g., amiloride, spironolactone, triamterene) without careful monitoringSolid oral dosage forms in patients with gastrointestinal obstruction or delayed gastric emptying

Clinical Precautions

PrecautionsCardiac arrest and fatal arrhythmias if given undiluted or too rapidly, Hyperkalemia risk in patients with renal impairment, GI ulceration with oral formulations, Monitor serum potassium levels regularly
Food/DietaryAvoid high-potassium foods (bananas, oranges, tomatoes, potatoes, spinach) in large amounts unless specifically advised. Limit salt substitutes (contain potassium chloride). No significant interaction with alcohol or caffeine.

Clinical Tips & Counseling

Clinical PearlsMaximum infusion rate for peripheral lines is 10 mEq/h; central lines allow up to 20 mEq/h. Never administer IV undiluted; must be diluted to ≤ 0.1 mEq/mL. ECG monitoring required for rates >10 mEq/h. Contraindicated in severe renal impairment (CrCl <30 mL/min), hyperkalemia, and concomitant potassium-sparing diuretics. Use with caution in patients on digoxin due to arrhythmia risk.
Patient AdviceTake with food or after meals to reduce stomach upset. · Do not crush or chew extended-release tablets; swallow whole. · Avoid salt substitutes containing potassium unless directed by doctor. · Report symptoms of high potassium like muscle weakness, irregular heartbeat, or tingling in hands/feet. · Do not stop abruptly; may cause low potassium symptoms. · Keep medication in original container; protect from moisture.

POTASSIUM CHLORIDE 40MEQ Interactions

Loading safety data…

This overview is compiled from peer-reviewed clinical sources and FDA labeling. It's here to support — not replace — clinical judgment. Always verify dosing against your institution's current protocols before prescribing.

On this page

Mechanism of ActionDosing & administrationUse during pregnancyWarnings & precautionsDrug interactions

Compare with

POTASSIUM CHLORIDE 15MEQ IN DEXTROSE 5% AND LACTATED RINGER'S IN PLASTIC CONTAINERPOTASSIUM CHLORIDE 20MEQPOTASSIUM CHLORIDE 20MEQ IN DEXTROSE 5% AND LACTATED RINGER'S IN PLASTIC CONTAINERPOTASSIUM CHLORIDE 20MEQ IN DEXTROSE 5% IN PLASTIC CONTAINERPOTASSIUM CHLORIDE 20MEQ IN PLASTIC CONTAINER

External sources

DailyMed (NIH) PubMed OpenFDA