One of the most commonly prescribed brand name drugs in the U.S., the cholesterol-lowering drug Crestor, will become available in a generic version later this year.

If you've been paying high co-pays for brand-name Crestor, you'll likely get an immediate price break if you switch to the generic version, since co-pays are typically less for generics than branded drugs. But experts say it may be months—or even longer—before those who pay the entire cost of the drug out of their own pocket see substantial savings.

Drugmaker AstraZeneca holds the patent on Crestor and has exclusive rights to market the drug until July. But the Food and Drug Administration (FDA) has already issued tentative approval to several companies for the generic version of the drug, rosuvastatin. One of those manufacturers, Actavis, negotiated a deal with AstraZeneca to bring the generic to the market as early as May of this year.

While Actavis wouldn't respond to our request for information about the debut price for generic Crestor, it’s likely to be only about 10 to 20 percent less than the retail price for brand-name Crestor (currently about $284 for a 30-day supply), says Stephen Schondelmeyer, Pharm.D., Ph.D., a professor of pharmaceutical economics at the University of Minnesota in Minneapolis.

“Americans won’t realize significant savings on rosuvastatin until a second and even a third generic manufacturer enters the market to create competition,” says Schondelmeyer. “That could take six months to a year—or possibly even longer.”

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"Sticky Pricing" Keeps Costs High

Even after several generic makers enter the market, retail pharmacies such as CVS, Rite Aid, and Walgreens sometimes keep the list price of a new generic set high, a practice Schondelmeyer refers to as “sticky pricing.” 

That's one of several reasons Consumer Reports has found that many people are paying more for their medications.

“While some pharmacies drop the price as generics enter the market, others will hold it near the brand-name price as long as possible.” They get away with it, he says, because many customers who have health insurance pay a set co-pay regardless of the retail price. But those consumers who pay the entire cost of the drug themselves because they don’t have insurance or have a high deductible may not see the substantial savings that should come with generic availability.

Last year, Consumer Reports Best Buy Drugs' pricing survey found lots of sticky pricing when secret shoppers called to check the price of common generic medications at more than 200 drugstores around the U.S. For example, they discovered that CVS drugstores still priced the cholesterol-lowering drug atorvastatin (the generic version of Lipitor) at $146 for 30 days worth, even though generic versions have been available since the fall of 2011. On the other hand, Costco’s price for the same drug was $18.

The lesson here, says Schondelmeyer, is that people who don't have good prescription drug coverage have to shop around. “Don’t assume that just because there is a generic, that it is a lot cheaper than the branded version, or that you’re getting a great deal,” he says.

In the case of generic Crestor, check prices again after the drug has been available for six months to a year as, over time, some generic drugmakers and drugstores are bound to reduce the price more than others.

See more tips for ways to save on prescription drugs.    

Do You Really Need Crestor?

There's no reason to pay a premium for brand-name Crestor. That's according to our Best Buy Drug report on statin drugs to treat high cholesterol. But when the less expensive generic version of rosuvastatin becomes available, that may be a reasonable choice.

Still, even if you have good prescription drug coverage, you should review your options carefully, as other statins may still be cheaper than generic Crestor.

For example, if you haven’t had a heart attack and need to reduce your cholesterol levels by less than 50 percent, Consumer Reports Best Buy Drugs recommends generic pravastatin (40 mg) or generic simvastatin (20 mg or 40 mg) as Best Buys based on effectiveness, safety, and cost. Many drugstores offer those cholesterol medications at a low cost of $4 for a month’s supply or $10 for three month’s worth.

Editor's Note: These materials were made possible by a grant from the state Attorney General Consumer and Prescriber Education Grant Program, which is funded by a multistate settlement of consumer fraud claims regarding the marketing of the prescription drug Neurontin (gabapentin).