For the past few years, Peggy Lewis has paid $10 or less for a 90-day supply of her gout drug, colchicine. But Lewis, 71, fears she will soon be forced to pay hundreds of dollars more for that medication.

Lewis, of Fairfield, Ohio, has taken colchicine for about 20 years to prevent attacks of gout, a form of arthritis that causes flares of sudden pain, stiffness and swelling in joints.

But sometime in 2010, Lewis will have to replace her current version with a brand-name colchicine medication, Colcrys, which, she was told, could cost up to $550 for a 3-month supply.

“I think it’s a shame," she says of the price increase. “It would take my whole Social Security check."

The jump in price follows a push by the U.S. Food and Drug Administration (FDA) to stop the sale of hundreds of medications that had been grandfathered onto the drug market because they were dispensed before the agency began reviewing and approving new drugs.

Colchicine, for example, which is made from a flowering plant called the Autumn Crocus, was first used for gout treatment in the 1800s.

It’s estimated that thousands of drugs fall into this “marketed, unapproved” category, and they include many other medical mainstays, including forms of the painkiller morphine and the heart drug nitroglycerine.

The agency says it is concerned that many of these medications could have safety issues that have never been brought to light. In 2008, for example, the FDA banned injected forms of colchicine after 23 deaths were linked to its use.

The FDA has called on drug manufacturers to conduct clinical trials on these unapproved medications. In return, the Agency offers them some patent protections so they can recoup their investments in the drugs.

In 2009, Philadelphia-based company, URL Pharma, which is thus far the only company that has tested colchicine and submitted an application for FDA approval, was granted the exclusive rights, for three years, to market colchicine as a treatment for gout attacks. The company was also granted the right to be the sole supplier of colchicine as a treatment for familial Mediterranean fever, a rare disease, for seven years.

Colchicine currently accounts for about 3.5 million prescriptions in the U.S. annually, according to IMS Health.

Pharmacies still carry the unapproved, generic versions of colchicine, but as these versions are forced off the market, at some point, those supplies will dry up.

When that happens, the price of colchicine is expected to soar from about $.10 to $5 per tablet.

The steep increase of Colcrys has alarmed both patients with these diseases and the rheumatologists who treat them.

“Rheumatologists are incensed – there’s anger out there," says Edward Herzig, MD, an Ohio rheumatologist who treats Lewis.

In response to the price uproar, URL Pharma points out that their testing of colchicine revealed that lower doses were equally effective as the dose commonly prescribed by doctors. The company also points to newly-identified drug interactions between colchicine and some kinds of antibiotics and antifungal drugs, which might not have been identified without its research.

The company also promised to expand its patient assistance and co-pay programs, which, the company says, should make Colcrys affordable to all.

Nevertheless, the American College of Rheumatology in January said it asked the FDA to prolong the typical "grace period" of one year before forcing other colchicine makers to halt production.