Potassium Chloride vs Potassium Citrate

Today I encountered an interesting drug information question regarding the various potassium products that were available. I have summarized my findings in the table below. Additionally, the question arose as to whether or not potassium citrate and potassium chloride could be used interchangeably; if not, what is the difference in these two salts?

The answer is no, these are not equivalent products. Unlike potassium chloride, potassium citrate does not have an FDA-approved labeled indication for the treatment of  hypokalemia. Potassium citrate's three indications are as follows:

• Prevention of uric acid nephrolithiasis
• Prevention of calcium renal stones in patients with hypocitraturia 
• Urinary alkalinizer for situations in which sodium citrate is contraindicated

Mechanism of Action:

Oral administration of potassium citrate produces an alkaline load, as the citrate is converted hepatically to bicarbonate. This increases the urinary pH and further enhances the clearance of citrate, thus increasing urine citrate concentration. Also, the bicarbonate may reduce bone resorption (release of calcium from bone to blood via action of osteoclasts) and increased renal calcium reabsorption. These combined effects may lead to a transient decrease in urinary calcium, and makes the environment of the urine less conducive to the crystallization of stone-forming salts. Increased urinary PH also causes uric acid's more soluble urate ion to form, thus decreasing the risk of uric acid stones. 

GENERIC	DOSAGE FORM	BRAND NAMES	AVAILABLE STRENGTHS	INDICATIONS
Potassium Chloride	Extended-release capsules	Micro-K	8 mEq; 10 mEq	·         Treatment/prevention of hypokalemia ***K-TAB NOT BIOEQUIVALENT
	Oral Solution	K-Sol	20 mEq/15 mL ; 40 mEq/15mL
	Oral packet	K-Vescent	20 mEq
		Klor-Con	20 mEq; 25 mEq
	Extended-release tablets	K-Tab	8 mEq; 10 mEq; 20 mEq
		Klor-Con	8 mEq; 10 mEq; 15 mEq; 20 mEq
Potassium Citrate	Extended release tablets	Urocit-K 5	5 mEq	·         Prevention of uric acid nephrolithiasis ·         Prevention of calcium renal stones in patients with hypocitraturia ·         Urinary alkalinizer when Na-Citrate contraindicated
		Urocit-K 10	10 mEq
		Urocit-K 15	15 mEq
Potassium Gluconate (1gm = 4.3 mEq)	Capsules	K-99	595 mg	·         Dietary supplement
	Tablets	(generic)	2 mEq; 2.5 mEq; 8mg (base)
Potassium Acid Phosphate (500mg = 3.7 mEq)	Tablets	K-Phos	500mg	·         Acidify urine—lower urine calcium concentration ·         Reduce odor and rash from ammonia in urine ·         Synergistic effect with antibacterial activity of methenamine
Potassium Bicarbonate/Potassium Citrate	Tablets (for solution)	Effer-K	10 mEq; 20 mEq	·         Treatment/prevention of hypokalemia (if avoiding chloride or acid/base status requiring bicarb)
		Klor-Con/EF	25 mEq
Potassium Iodide	Oral Solution	SSKI	1 gm/mL	·         Expectorant; chronic pulmonary diseases complicated by mucus ·         Block uptake of radioactive isotopes
		ThyroShield	65 mg/mL
Potassium  P-aminobenzoate	Capsules	M2 Potassium	60 mg	·         Scleroderma ·         Dermatomyositis ·         Morphea ·         Pemphigus ·         Peyronie’s Disease
		Potaba	500 mg
	Packet	(generic)	2g
	Tablets	Potaba	500 mg

References:

1. Lexicomp. Accessed 7/31/2015. <www.online.lexi.com.proxy.lib.uiowa.edu>

2. Drugs.com. Accessed 7/31/2015 <http://www.drugs.com/pro/potassium-citrate.html>

3. Krieger NS, Asplin JR, Frick KK, et al. Effect of Potassium Citrate on Calcium Phosphate Stones       in a Model of Hypercalciuria. J Am Soc Nephrol. 2015.