Pfizer's drug to treat tuberculosis in short supply Mon Mar 25, 2013 12:47pm EDT (Reuters) - The Food and Drug Administration has added Pfizer Inc's tuberculosis treatment rifampin to its list of drugs in short supply, the latest in a growing number of spottily available TB medications. The FDA noted in a post on its website on Monday that the injectible antibiotic will be in short supply until the end of June. The cause of the shortage is a manufacturing delay, it said. Rifampin is one of the most potent and widely used TB drugs, and its shortage comes amid an increased prevalence of the disease around the world, though TB rates in the United States fell to an all-time low last year. In a letter to physicians dated March 18, Pfizer said a number of vials of the medication may not meet the specifications for drug potency, and exhibited a change in color from the expected red powder to brown or black. The company said it was investigating the matter. At the end of last year, the FDA approved a new TB drug made by Johnson & Johnson for patients who do not respond to other treatments. It is the first in 40 years to tackle the disease using a new mechanism of action. In 2011, nearly 9 million people around the world became sick with TB, according to the Centers for Disease Control and Prevention, and there were 1.4 million TB-related deaths. Reporting by Toni Clarke in Washington; Editing by Dale Hudson