80% of Nitroglycerin Pills Unapproved, NY Times Reports

FDA sends out warning letters about unapproved nitroglycerin

March 29, 2010

March 29, 2010 (New York, NY) - Around 80% of the almost five million prescriptions for sublingual nitroglycerin tablets dispensed in the US last year were unapproved medications because of a loophole in FDA regulations relating to drugs developed before it was founded, in 1938, says an article in the New York Times [1].

The agency has now decided to tackle the problem as part of its Unapproved Drugs Initiative announced in 2006 to address marketed drugs that have not received FDA approval. On March 16, 2010, it sent warning letters to two manufacturers of 0.3-mg, 0.4-mg, and 0.6-mg dosages of unapproved nitroglycerin [2]--Konec of Tucson, AZ [3] and Glenmark Generics of Mahwah, NJ [4]--giving them 90 days to stop making the products and 180 days to stop shipping them.

"The unapproved nitroglycerin tablets have not been proven safe and effective, and the FDA has not reviewed the quality and labeling of these products. The unapproved products may differ from approved nitroglycerin products in some respects, such as formulation and labeling," the agency notes.

The letters did not, however, demand a recall, so the manufacturers have six months to continue marketing their unapproved nitroglycerin tablets, notes the report, and some major pharmacy companies said they would continue to sell the unapproved products.

Cardiologists told Times reporter Natasha Singer that they were shocked to discover this. ACC president Dr Ralph Brindis (University of California, San Francisco) said he was "taken aback." And Dr Harry M Lever (Cleveland Clinic, OH) commented: "If it's not approved and no one has tested it, we can't be sure that it's safe and effective. Every day when I write a prescription, I'm thinking, 'Is the patient going to get the right stuff?' "

The FDA has advised patients who are taking unapproved nitroglycerin products to continue taking their medication but to consult their physicians for guidance on alternative treatments.

Contacted by a reporter from the New York Times, Konec said its tablets had equivalent safety and potency to the only approved brand-name nitroglycerin product, Nitrostat (Pfizer), but admitted it had not conducted bioequivalence studies required for the approval of a generic drug. The company now plans to perform such tests and submit its product for approval as a generic. And a spokesperson for Glenmark Pharmaceuticals in India, the parent company of Glenmark Generics, said it would comply with the FDA's directive to stop making the unapproved products.

Pfizer said it had stepped up production of Nitrostat and expected to be able to meet the entire market demand for nitroglycerin in the US.