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How much potassium chloride to add to fluids for a dog or cat
Potassium chloride is added to IV fluids by the serum potassium, from 20 mEq/L at a normal potassium up to 80 mEq/L below 2.0 mEq/L, and the Vetinuity potassium chloride calculator below keeps the delivered rate at or under 0.5 mEq/kg per hour.
Potassium chloride doses at a glance
| Species | Use | Dose | Route and interval |
|---|---|---|---|
| Dog or cat | Serum K 3.6 to 5.0 mEq/L (maintenance) | 20 mEq per litre of fluid | IV, fluid rate up to 25 mL/kg/h |
| Dog or cat | Serum K 3.1 to 3.5 mEq/L | 28 mEq per litre | IV, up to 18 mL/kg/h |
| Dog or cat | Serum K 2.6 to 3.0 mEq/L | 40 mEq per litre | IV, up to 12 mL/kg/h |
| Dog or cat | Serum K 2.1 to 2.5 mEq/L | 60 mEq per litre | IV, up to 8 mL/kg/h |
| Dog or cat | Serum K below 2.0 mEq/L | 80 mEq per litre | IV, up to 6 mL/kg/h |
Vetinuity potassium chloride dose calculator
Why the cap is 0.5 mEq/kg per hour
Potassium given faster than about 0.5 mEq/kg per hour risks bradyarrhythmias and cardiac arrest, so every row of the chart pairs a concentration with the fastest fluid rate that keeps the patient under that ceiling1,2. The risk comes from the rate, not the bag: 80 mEq/L is safe at 6 mL/kg/h and dangerous as a shock bolus. Bolus fluids are therefore never run from a supplemented bag, and the potassium bag goes on a pump.
Mixing the bag
Potassium chloride concentrate is 2 mEq/mL. Adding 20 mEq to a 1 litre bag takes 10 mL; 40 mEq takes 20 mL. Invert the bag several times after injecting, because the concentrate is denser than the fluid and can pool at the bottom and run in as a bolus. Commercial fluids already carry some potassium (lactated Ringer's has 4 mEq/L), which is small enough to ignore at the low rows and is counted at the high ones.
Rechecking potassium
Recheck serum potassium every 4 to 12 hours while the supplemented rate is high, and move up or down a row as the value changes3. A potassium that will not rise despite the chart points to ongoing losses or to low magnesium, which drives renal potassium wasting and should be measured and corrected1. Insulin, dextrose, bicarbonate and beta agonists push potassium into cells, so a DKA patient often needs a higher row within hours of starting insulin2.
Oral potassium in cats with kidney disease
Hypokalemia is common in cats with chronic kidney disease, and the ISFM guidelines support oral potassium gluconate or citrate for hypokalemic cats, adjusted to the serum value at each recheck4. Oral supplementation is the maintenance route; the IV chart above is for hospitalized patients.
Related values on this site: Potassium, Chloride, Creatinine.
Frequently asked questions
What is the maximum IV potassium rate for a dog or cat?
0.5 mEq/kg per hour. Every row of the chart is built so the fastest allowed fluid rate stays at or under that ceiling1.
How many mL of potassium chloride go into a litre bag?
The concentrate is 2 mEq/mL, so divide the mEq per litre by 2: 20 mEq/L needs 10 mL, 40 mEq/L needs 20 mL.
Why is the potassium still low after a day on supplemented fluids?
Ongoing losses, a shift into cells from insulin or alkalosis, or low magnesium are the usual reasons1,2.
Sources
- Hoehne SN. Therapy of Potassium Disorders. Vet Clin North Am Small Anim Pract. 2026; 56(1):155-167. PMID: 41107159. DOI: 10.1016/j.cvsm.2025.09.017.
- Schaer M. Therapeutic approach to electrolyte emergencies. Vet Clin North Am Small Anim Pract. 2008; 38(3):513-33, x. PMID: 18402878. DOI: 10.1016/j.cvsm.2008.01.012.
- Feo Bernabe L, Autran de Morais H. A Quick Reference on Hypokalemia. Vet Clin North Am Small Anim Pract. 2026; 56(1):75-83. PMID: 41087252. DOI: 10.1016/j.cvsm.2025.09.010.
- Sparkes AH, Caney S, Chalhoub S, et al. ISFM Consensus Guidelines on the Diagnosis and Management of Feline Chronic Kidney Disease. J Feline Med Surg. 2016; 18(3):219-39. PMID: 26936494. DOI: 10.1177/1098612X16631234.