Popular medications are going on the cheap

In the next 14 months, seven of the world's 20 best-selling drugs will be available in generic form, dramatically slashing the cost for patients but also decimating sales for the drug companies that created them. CBS News correspondent Ben Tracy explains what they are and what this means.

Marvelene Bickerstaff takes 9 medications every day -- and it's not cheap.

It costs her "at least $200 per month," she said. "And that's why I still work, because I am 74 years old now."

Her diabetes drug, Byettta, costs $75 a month, so she begs her doctor for samples to cut costs.

"Maybe four to five months out of the year I can get a sample," she added.

Over the next decade, patents on dozens of brand name drugs are expiring. That clears the way for generic versions which work just as well and cost much less.

So what are the two biggest drugs to go generic? Cholosterol drug Lipitor in November and blood thinner Plavix in May 2012. About 4.3 million Americans take Lipitor, while 1.4 million are on Plavix.

Cheaper pills? 7 top-selling drugs set to go generic

"I've seen people that couldn't afford the brand name," said pharmacist Nicky Rasmi-Shamsi. "Their insurance doesn't cover it or the co-pay was way too high, and they just had to either go without or take a medication that wasn't comparable."

Generic drugs cost 20 to 80 percent less than brand names. When heartburn drug Protonix went generic, the price dropped from $170 per month to just $16.

By 2016, dozens of popular drugs -- Lexapro, Avandia, Lunesta, Singulair -- with $255 billion in global sales will go generic. Pharmaceutical company profits are expected to plunge.

It's hard to feel too sorry for big drug companies, but a portion of the giant profits they make goes back into creating new drugs. With less money coming in they may not spend as much on innovation and could cut jobs.

But for Marvelene Bickerstaff, the savings could be $50 a month.

"That's a big difference," she said. "Big difference. That's lunch money for two or three more weeks if you're still working."

The generic drugs save the U.S. healthcare system much more -- an estimated $1 billion dollars every three days.