In this episode, I’ll discuss the dose of insulin to use when treating hyperkalemia.
Hyperkalemia treatment generally includes 3 steps:
1. Protect the cardiac membrane with IV calcium
2. Hide the potassium from the heart
3. Remove the excess potassium from the patient
Insulin works in step #2. I think of insulin like a key that unlocks a door in cell membranes to allow glucose, potassium, and water to walk through. This hides the potassium from the heart, preventing arrhythmias until the excess potassium can be removed. The intracellular concentrations of sodium and potassium are essentially the reverse of the plasma concentrations. This is why a couple extra mEq/L of potassium doesn’t do any harm inside cells, but has a tremendous impact on the outside of cells.
While the standard dose of insulin to treat hyperkalemia is 10 units, this dose may result in excessive hypoglycemia, even when IV dextrose is given at the same time.
The dose of 10 units is also completely arbitrary and has never been subjected to a dose-finding study.
In the journal Pharmacotherapy, authors recently published a meta analysis looking at Reduced Alternative Insulin Dosing in Hyperkalemia.
10 studies, all retrospective cohorts, involving more than 3400 patients were analyzed. Dosing strategies for insulin in hyperkalemia included 5 units, 0.1 units/kg, and <10 units.
The authors found that compared with 10 units of insulin, these lower dosing strategies had an odds ratio for hypoglycemia of 0.55 and for severe hypoglycemia of 0.41.
At the same time, there was no difference in potassium reduction between the different doses of insulin used.
This meta-analysis suggests that using less than 10 units of insulin is reasonable for treating hyperkalemia. Prospective studies will need to be performed to identify the best dose to use.
Members of my Hospital Pharmacy Academy have access to practical training from a pharmacist’s point of view on the management of severe hyperkalemia, as well as over 150 other practical trainings in video and audio format. This is in addition to many other resources to help in your practice. To get immediate access, go to pharmacyjoe.com/academy.
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