China White epidemic: an eastern United States emergency department experience. STUDY OBJECTIVE: The purpose of this study was to isolate significant clinical or demographic findings concerning overdose patients treated during a China White (3-methyl fentanyl) epidemic and compare them with data for all unintentional narcotic overdose patients during a 24-month period. DESIGN: We reviewed charts from 85,246 patient visits to our emergency department during the 24-month period of January 1987 through December 1988 to study this narcotic epidemic. Data from the Allegheny County Coroner's Office pertaining to unintentional drug overdose deaths that occurred during this same period also were reviewed. SETTING: The first outbreak of narcotic overdoses in the eastern United States involving China White occurred in Allegheny County, Pennsylvania, in 1988. TYPE OF PARTICIPANTS: Patients were included if they met the criteria of a suspected unintentional narcotic overdose, but excluded if they were not given naloxone. INTERVENTIONS: Emergency physicians became suspicious of China White use after an unusual increase in narcotic overdoses presenting to the ED coupled with "routine drug of abuse" screens negative for opiates despite dramatic patient responses to naloxone. In most of the cases in which specific testing was done, there were positive indicators of fentanyl derivatives. Investigations found China White present in street drugs and paraphernalia. MEASUREMENTS AND MAIN RESULTS: A cluster was defined as a time period with a statistically significant increase in overdoses over the expected number for an interval of equal length. Although there were no significant clinical differences in case presentation during the 24-month period, there was a statistically significant 13-fold increase in overdoses during the September through November 1988 cluster (mean, 13 vs 0.95 per month, P less than .001 by Wilcoxon rank-sum test). A dramatic increase in unintentional drug overdose deaths occurred in the county during this cluster. A total of 18 fentanyl-positive unintentional drug overdose deaths, predominantly male (89%) and black (56%), with an age range of 19 to 44 years (mean, 34.9 years), were reported by the county coroner (13 during the cluster). Narcotic overdoses and unintentional drug overdose deaths declined sharply with confiscation of a clandestine China White laboratory. CONCLUSIONS: China White was responsible for a dramatic rise in unintentional drug overdose deaths in Allegheny County in 1988. There were no significant clinical differences between China White overdose survivors and other unintentional narcotic overdose victims. Overdoses responsive to naloxone with inconsistent routine toxicologic screens may be due to a fentanyl analogue. 