Figure 1.8 compares current (nominal) prices of different generations of antibiotics. There is a general increasing trend in prices, with newer antibiotics, such as oxazolidinones and quinolones, costing much more than penicillins, sulfonamides, and other older drugs. Since most antibiotics, with the exception of the most recent ones, are off patent, the higher cost of relatively newer drugs likely reflects the enormous regulatory costs of bringing a drug to market. To date, there has been only one analysis of the drug-related cost  of bacterial resistance. Howard and Rask (2002) take 1980 1998 data on antibiotics used to treat ear infections from the National Ambulatory Medical Care Survey to estimate the increase in the cost of antibiotic treatment attributable to increases in bacterial resistance. Lacking data on resistance, they used time trends as a proxy for resistance to show that between 1997 and 1998, increases in drug resistance are estimated to have raised the cost of treating ear infections by about 20 percent ($216 million). This approach is not perfect, however, since time trends may capture costs unrelated to resistance, such as the costs of antibiotics with lower  side-effect profiles or more convenient dosing.