P B Jayakumar / Mumbai July 19, 2008, 0:40 IST Amid reports of a US Congress probe against India's largest drug maker Ranbaxy Laboratories, data show that many leading multinational companies such as Pfizer, GlaxoSmithKline, Novartis and Merck are also under the scanner of the US drug regulator, for more or less similar violations as Ranbaxy is alleged to have committed. Data available from the US Food and Drug Administration (FDA) website reveal that the regulator has issued about 200 warning letters since January this year to various manufacturers, both in the US and outside, at an average of about 30-35 letters every month. These are mainly for deviating from manufacturing and quality assurance systems and for selling adulterated or misbranded products, the same charges levelled against Ranbaxy during the inspection of its Paonta Sahib facility in February 2006. Interestingly, records reveal that only three Indian drug companies have been served with warning letters