Doris Webb was diagnosed earlier this year with a rare disease called Familial Mediterranean Fever, a hereditary condition that causes fevers, arthritis attacks, and inflammation of the lining of the lungs and abdomen. Debilitating pain in her joints and bones was relieved by a prescription drug called colchicine.

Webb, of Morristown, Tenn., takes two to three tablets a day, paying $11 at Wal-Mart for a 90-day supply, according to her daughter, Tina Martin, who also takes colchicine for FMF. The drug, which has long been used to treat gout, is cheap; like thousands of prescription drugs, it predates modern drug laws and is not approved by the Food and Drug Administration.

Webb, 66, who's on Medicare but cannot afford the Part D drug benefit, faces a problem in getting her colchicine. In July, Philadelphia-based URL Pharma won FDA approval for a branded version called Colcrys, which sells for about $4.50 a tablet – nearly 50 times the price of the unapproved version. While the uninsured will be hit hardest by the cost increase, even insured patients, like Martin, will face higher costs. She says her co-payment will rise from $10 to $35 for a 90-day supply.

The FDA found that Colcrys' drug-interaction labeling and recommended dosing regimen make it safer than the unapproved forms of colchicine. The agency said it had received reports of 120 patient deaths from interactions of unapproved colchicine with other drugs. It granted URL Pharma and Colcrys three years exclusivity for treatment of gout - a recurrent arthritic inflammatory disease caused by uric-acid buildup.

There were about 3.5 million colchicine prescriptions filled in 2009, according to IMS Health. There are an estimated five million gout sufferers in the United States, and fewer than 200,000 FMF patients.

Colchicine is the latest drug targeted by the FDA under a 2006 initiative aimed at prodding drugmakers to go through the agency's lengthy and costly approval process.

Recently, the American College of Rheumatology sent a letter to the FDA seeking a meeting to discuss how to keep colchicine affordable to patients. "We want to express our concern that a medicine used for centuries to treat gout and rare conditions, which costs pennies, will now cost patients quite a bit more," said Dr. Stanley Cohen, who is the Dallas-based president of the group.

Part of URL Pharma's business plan is to take advantage of the FDA's campaign against unapproved drugs.

"Four years ago we decided to join the FDA in this effort," said Dr. Richard Roberts, CEO of URL Pharma. "We are focusing on a few of the unapproved products where there are significant safety and medical issues, applying a lot of science and creativity to bring them into compliance and make them safer."

In 2005, the company won FDA approval for Qualaquin, a brand-name formulation of unapproved quinine sulfate, long used for treating malaria. The following year, the FDA halted sales of quinine sulfate.

In its 2006 policy guide, the FDA estimated there are several thousand drugs being marketed without the agency's approval. Federal law required approval of new drugs for safety beginning in 1938, and for effectiveness in 1962. Many drugs, like colchicine, currently on the market preceded those laws.

Cheap colchicine probably won't be on the market for long. URL Pharma is suing to force the unapproved products off the market. Whatever the outcome of that lawsuit, the FDA policy guide suggests the drug agency will give other colchicine-makers a year from Colcrys' approval before moving to halt sales.

Attempts to reach colchicine producers were unsuccessful.

Roberts argues that it's unfair to compare the price of Colcrys and unapproved colchicine. "The companies pushing out illegal products with no regard for safety issues didn't add value for patients and doctors that we've now created," he said.

URL Pharma is reaching out to calm the consternation over the price of its new product. It's offering a three-month supply of Colcrys for $15 to any U.S. patients with incomes under three times the poverty level. FMF patients with private insurance will qualify for coupons limiting their co-payment to $25 per prescription.