That consumers are hesitant to purchase off-brand OTC drugs is not only a tribute to the marketing power of the brand-name OTC drug companies, but also consumers' experience with private label brands in other arenas, such as grocery products.

"If you've had a bad experience with a private label brand in another setting you might be less willing to buy an off-label or store-brand OTC medication," says Mary Jenkins, vice president of clinical services for Innoviant, a pharmacy benefits administrator and unit of Fiserv Health.

Same factory, different box
What consumers don't realize is that in many cases, the brand-name and off-brand drug may be produced in the same factory, just placed in different boxes. So a store-brand bottle of pain-relieving ibuprofen may come from the same manufacturer as the brand-name ibuprofen.

So why do consumers keep going for the more expensive store brand?

"Expectations," says Jenkins. "These big consumer products companies spend millions of dollars in direct-to-consumer advertising to create a perception among consumers that they are safer and more reliable."

Findlay agrees, noting that not only do manufacturers of brand-name OTC drugs spend heavily on advertising, but their products also tend to be more "front and center on store shelves," where such placement is more likely to catch the eye of a consumer in a hurry.

"Despite all the evidence of the past 20 years that there is no difference between brand and off-brand OTC medications, consumers continue to buy the more expensive drugs, even though they could save considerable amounts of money by purchasing less expensive versions of the same drug," he says.

Read the label
With so many versions of brand-name and off-brand over-the-counter medications -- there are more than 20 different versions of Tylenol for pain relief, colds and allergies, for example -- it can be difficult to compare brand names to each other and to off-brands to make sure that you're getting exactly the medication that you need. But armed with some knowledge, a few minutes and help from your local pharmacist, it is possible to save a significant amount of money in shopping for OTC drugs.

You can find out on the back of the box whether a particular brand-name OTC drug designed to treat a particular condition is identical to another brand-name OTC drug or an off-brand name OTC medication, says Sean Karbowicz, clinical pharmacy manager for Regence Blue Cross Blue Shield.