Comparing Potassium Chloride To Potassium Gluconate

The pharmacist compares dosing for potassium gluconate and potassium chloride as well as other differences between the two potassium salt forms.

Question

What are the differences between potassium chloride ER 20 mEq and Nature Made Potassium Gluconate 550 mg? The purpose is to alleviate nighttime leg cramps. Am I choosing an appropriate replacement?

Asked by Andy On Jul 30, 2018

Answered by
Medical Content Reviewed By PharmacistAnswers Staff

On Aug 02, 2018

It can sometimes be difficult to understand the difference in potassium products, as we are dealing with different units of measure (mEq vs. mg) and different salt forms (chloride vs. gluconate).


We'll first discuss conversions between the two in regard to attaining the same amount of 'elemental' potassium and then we'll discuss specific characteristics of each.


Coverting Potassium Chloride To Potassium Gluconate

Below, we get into the specifics regarding how to discern how much elemental potassium is in each product. Overall:

  • 2,350 mg of potassium gluconate is equivalent to 10 mEq of potassium chloride in terms of elemental potassium content (390 mg of elemental potassium).
  • 4,700 mg of potassium gluconate is equivalent to 20 mEq of potassium chloride in terms of elemental potassium content (780 mg of elemental potassium).


Potassium Chloride To Elemental Potassium

Potassium chloride, as a prescription, is measured in mEq or milliequivalents. The most common strengths are:

  • 8 mEq
  • 10 mEq
  • 15 mEq
  • 20 mEq


Each milliequivalent of potassium chloride contains 75 mg. Therefore:

  • 8 mEq of potassium chloride contains 600 mg
  • 10 mEq of potassium chloride contains 750 mg
  • 15 mEq of potassium chloride contains 1,125 mg
  • 20 mEq of potassium chloride contains 1,500 mg


Now, even though we have the total milligram quantity of potassium chloride, we need to do a further conversion to find out how much elemental potassium is contained within potassium chloride.


Potassium chloride contains 52.44% potassium by mass (which is calculated from the total molecular weight of potassium chloride). Therefore:

  • 600 mg of potassium chloride contains 314 mg of elemental potassium.
  • 750 mg of potassium chloride contains 393 mg elemental potassium (often rounded to 390 mg).
  • 1,125 mg of potassium chloride contains 590 mg elemental potassium.
  • 1,500 mg of potassium chloride contains 786 mg elemental potassium (often rounded to 780 mg).


Below is the complete breakdown of the common potassium chloride strengths:

  • Potassium Chloride 8 mEq = 600 mg of potassium chloride = 314 mg of elemental potassium
  • Potassium Chloride 10 mEq = 750 mg of potassium chloride = 393 mg elemental potassium
  • Potassium Chloride 15 mEq = 1,125 mg of potassium chloride = 590 mg elemental potassium
  • Potassium Chloride 20 mEq= 1,500 mg of potassium chloride = 786 mg elemental potassium

Potassium Gluconate To Elemental Potassium

Potassium gluconate contains much less potassium by mass than potassium chloride. It contains only 16.69% potassium by mass. Therefore, if your potassium gluconate supplement contains 550 mg, it only contains around 91 mg of elemental potassium.


To illustrate how much elemental potassium is in potassium gluconate, let's look at the label of the supplement you mentioned (Nature Made Potassium Gluconate 550 mg):

Potassium Gluconate

The label confirms what we have above, that there is approximately 16.69% elemental potassium by mass in potassium gluconate (550 * 0.1669 = 91).


Additional Information

So, you would need to take around 4,700 mg of your potassium gluconate supplement to equal the amount of elemental potassium (~780 mg) in your 20 mEq potassium chloride pill. Since your potassium gluconate supplement contains 550mg per pill, that equates to about 8.5 tablets.


What Is The Difference Between Potassium Chloride And Potassium Gluconate

Aside from potassium chloride containing far more elemental potassium by mass (52% VS. 16.7%) than potassium gluconate, there are other significant differences between the two:

  • Potassium chloride is often the potassium salt of choice for most individuals as chloride loss is very common in those taking diuretic medications (e.g. hydrochlorothiazide) or in those who have excessive diarrhea/vomiting.
  • Potassium chloride has better GI absorption than other potassium salts.
  • Potassium gluconate may be an option for those looking to restrict chloride intake.
  • Potassium gluconate is alkaline (compared to potassium chloride, which is acidic). The alkaline characterisctics may help in those with metabolic acidosis, or in those susceptible to kidney stones.


Final Words

Although we have provided rough conversions and compared potassium chloride and potassium gluconate, it is important to note that you should not try to take prescription strengths of potassium if you are not under the supervision of a doctor. Taking too much potassium can cause serious side effects like heart arrhythmias.

About the Pharmacist

Dr. Brian Staiger Pharm.D

Dr. Brian Staiger is a licensed pharmacist in New York State and the founder of PharmacistAnswers.com. He graduated from the University At Buffalo with a Doctor of Pharmacy degree in 2010. He has been featured in numerous publications including the Huffington Post as well as a variety of health and pharmacy-related blogs. Please feel free to reach out to him directly if you have any inquiries or want to connect! He's answered thousands of medication and pharmacy-related questions and he's ready to answer yours! Brian.Staiger@PharmacistAnswers.com Office: 716-389-3076

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