ED visit rates for opioid analgesics were highest for oxycodone, hydrocodone, and methadone during the entire study period. Estimated ED visits involving oxycodone increased from 41,700 to 105,200 (p<0.001), and rates increased from 14.2 per 100,000 to 34.6 per 100,000, an increase of 144% (p<0.05). The estimated number of ED visits involving nonmedical use of benzodiazepines increased from 143,500 in 2004 to 271,700 in 2008 (89%, p=0.01), and rates increased from 49.0 to 89.4 per 100,000, an increase of 82% (p<0.05). The increases in numbers of ED visits during 2004-2008 for individual benzodiazepines were significant: alprazolam (125%, p=0.01), clonazepam (72%, p<0.001), diazepam (70%, p=0.02), and lorazepam (107%, p=0.006), as was the increase for the sleep aid zolpidem (121%, p=0.002). Carisoprodol-related visits also increased significantly (132%, p=0.04). The estimated number of visits for alprazolam in 2008 (104,800) was more than twice the number for the next most common benzodiazepine, clonazepam (48,400).