What is the difference between diclofenac sodium and diclofenac potassium?

Diclofenac is a non-steroidal anti-inflammatory drug (NSAID) used to relieve pain and reduce inflammation.

Diclofenac exists in two salt forms - diclofenac sodium (the sodium salt) and diclofenac potassium (the potassium salt). Each salt contains the same amount of diclofenac base. The main difference between the two salts is that diclofenac potassium is slightly more soluble in water than diclofenac sodium.

Diclofenac potassium is generally considered to be more quickly absorbed and have a faster onset of analgesic activity than diclofenac sodium.

Diclofenac is available in the following branded products for oral use:

• Cambia 50 mg (diclofenac potassium) for Oral Solution
• Zipsor 25 mg (diclofenac potassium) Liquid Filled Capsules
• Zorvolex 18 mg and 35 mg (diclofenac) Capsules

The following products have been discontinued:

• Cataflam 50 mg (diclofenac potassium) Immediate-Release Tablets
• Voltaren 25 mg, 50 mg and 75 mg (diclofenac sodium) Enteric-Coated Tablets
• Voltaren-XR 100 mg (diclofenac sodium) Extended-Release Tablets

The different formulations of diclofenac cannot be considered equivalent even if the dose is the same.