TUESDAY, Sept. 16 (HealthDay News) -- More than 30 generic drugs made by Indian drug maker Ranbaxy Laboratories Ltd. are being denied entry into the United States due to quality concerns at two of the company's factories, the U.S Food and Drug Administration announced Tuesday.

Ranbaxy is one of the world's largest producers of generic drugs. The FDA's Import Alert involves drugs such as the cholesterol-lowering drugs simvastatin and pravastatin and the antibiotic clarithromycin. Also on the list are HIV drugs lamivudine and zidovudine, as well as the diabetes drug metformin. The company also makes penicillin.

"FDA is taking this proactive step to ensure that drugs from these two facilities are not allowed into the United States until they meet FDA requirements for quality drug manufacture," Dr. Douglas Throckmorton, deputy director of FDA's Center for Drug Evaluation and Research, said during an afternoon teleconference Tuesday.

"To date, we have seen no evidence of harm to consumers from drugs produced at these two facilities and have no reason to believe that drugs already in the United States from these plans pose a safety problem," Throckmorton said.

He noted that U.S. shortages of these drugs are unlikely, as other manufacturers will be able to meet consumer demand.

However, Ranbaxy is the sole U.S. supplier of the antiviral ganciclovir capsules. To avoid a shortage of this drug, the FDA will not hold up shipments but will provide stepped-up oversight until the company fixes its problems, Throckmorton said.

"Based on what we know today, consumers who use products affected by this import alert should not discontinue their drug therapy, as such action could seriously jeopardize their health," Throckmorton said.

According to the agency, the two affected plants are the ones in Dewas and Paonta Sahib, India. The problems in these plants relate to deficiencies in the manufacturing process, the FDA said.

On Tuesday, the FDA told Ranbaxy that until it resolves these problems in its plants and complies with U.S, requirements, the agency will recommend denying approval of any new drug applications that list these plants as the manufacturer.

In August 2005, the FDA first received information about possible fraudulent practices at Ranbaxy. In 2006, the agency inspected Ranbaxy plants and found significant problems, Deborah M. Autor, director of FDA's Office of Compliance, Center for Drug Evaluation and Research, said during Tuesday's teleconference.

"These problems included failure to retain complete drug testing data, insufficient documentation to demonstrate stability tests were valid, and lack of sufficient laboratory personnel and instrumentation," Autor said.

Further investigation found inadequate sterile processing of penicillin products, Autor said. But, before Tuesday's action, the agency did not feel that an import alert was justified, she said.

"The deficiencies in the process have reached a level where we feel an import alert is justified," Autor said. "The firm is sufficiently out of control that we feel an import alert should be put in place until the deficiencies are corrected," she said.

In July 2008, the FDA charged Ranbaxy with forging and concealing documents relating to an investigation into the quality of the company's drugs sold in the United States. In addition, the agency filed a motion in the district court of Maryland asking for documents from Ranbaxy. The criminal case is continuing, Throckmorton said.

Ranbaxy is one of the largest suppliers of generic drugs to the United States and has worldwide sales of $1.61 billion, 25 percent -- or $386 million worth -- of which are to the U.S.

More information

For more about drugs on the import alert, visit the U.S. Food and Drug Administration.