And now we turn to healthy living -- the prescription drug equivalent of an earthquake. Lipitor the best selling drug ever goes generic at midnight tonight and it will be a huge loss in profits for... See More
And now we turn to healthy living -- the prescription drug equivalent of an earthquake. Lipitor the best selling drug ever goes generic at midnight tonight and it will be a huge loss in profits for the company that makes it Pfizer. But big savings for the eight point seven million Americans who take it. ABC's health and medical editor doctor Richard -- right here with us now so how much savings on average for the person taking them to me it's a lot and it starts tomorrow. Most patients pay thirty to fifty dollars as a co pay every month for Lipitor. That's gonna drop to an average of ten dollars a month. Enormous drop. And then in six months is -- -- be more companies making the generic form it may drop to as low as four dollars a month we're gonna see people who are more expensive drugs like -- for. Being switched over Lipitor but -- ingredients are not always exactly the same as the name brand ingredients is this. Just as effective and is it safe. Well I'm a big fan of generics when a lot of people think about -- they think about products in the supermarket spaghetti sauce the -- out like a flavor. Generic drugs the active ingredient has to be identical. There may be some -- -- near their little bit differently but for most patients who make no difference with the law ever be just as effective. OK doctor Richard -- are weighing in tonight this is big as we said.
This transcript has been automatically generated and may not be 100% accurate.