Yes and no. It's the same drug formulation but different strengths. Over-the-counter anti-inflammatory drugs are usually 200-250 mg. Prescription drugs by the same or similar names are around 400 mg.

Slight differences exist in the actual drug formulation of nonsteroidal antiinflammatories with similar names. You may have seen Naproxen sodium over-the-counter. This is also known as Aleve and other generic store brand names.

By prescription, there's Naproxen, Naprosyn, and Naprelan (same drug, different names). Also by prescription is Naproxyn sodium known as Anaprox, Anaprox DS, or EC-Naprosyn.

Drug companies can only keep drug formulas as their own for a limited number of years. Once they are released onto the market, then other drug companies can put the same or similar drug out with a slightly different name.

It can be very confusing. Don't take any drug without talking with your doctor first. A common mistake people make is to take the drug prescribed by the doctor along with the same drug at a lower dose over-the-counter. This can lead to serious complications.