NITROFURANTOIN ASSOCIATED LUNG DISEASE INCIDENCE RATE IS 0.00017%

NITROFURANTOIN ASSOCIATED LUNG DISEASE INCIDENCE RATE IS 0.00017%, Norwich Eaton maintained in June 11 comments to FDA. The company wrote in opposition to an April 20 citizen petition by Public Citizen which requested a box warning and a patient package insert to highlight the pulmonary complications associated with nitrofurantoin. Norwich Eaton calculated the chronic pulmonary reaction incidence rate based on a worse case scenario, comparing the total number of drug experience reports in the U.S. from all brands of nitrofurantoin (154) with the courses of therapy of Norwich Eaton's brand of nitrofurantoin (Macrodantin or Furadantin) consumed (90,000,000). The firm noted that the figure is based on both short-term and long-term usage of nitrofurantoin. For long-term use alone the company calculated an incidence rate of 0.0009%, based on market research data that indicate over 20% of nitrofurantoin use is for chronic urinary tract infection. Norwich Eaton maintained that since the warning in the current package insert went into effect in 1978, "the reported annual incidence of chronic pulmonary reactions in the U.S. has remained virtually constant, ranging from only 0.0001% to 0.0003%" and nothing has happened to show the labeling is inadequate. The firm said Public Citizen did not find the insert to be "insufficient in content or detail to alert a physician to this reaction," but instead was requesting that labeling "include specific directions to the physician." Norwich Eaton argued that "it is not the function of a package insert to dictate to the physician how to detect these symptoms in the patient." Public Citizen requested that the labeling specify that "close monitoring" of the patient includes chest x-rays and examinations and questioning about shortness of breath and cough. Norwich Eaton asserted that the chronic pulmonary reaction associated with nitrofurantoin "is no different from adverse reactions that occur with other prescription drugs." The company said "while the insidious nature of this reaction is acknowledged, it is not unlike those reactions observed with many other drugs, such as the hematologic reactions associated with amitriptyline and thioridazine, or the ocular disorders known to be associated with haloperidol and prednisone." Norwich Eaton said that it would be arbitrary for FDA to single out its drug and "mandate a patient package insert without having established that a patient package insert for nitrofurantoin would even be effective in preventing this complication in patients."