Ropinirole involved in a fatal case: blood and urinary concentrations

Purpose Ropinirole is an antiparkinsonian drug and has recently been suggested to be effective in amyotrophic lateral sclerosis. It is expected that ropinirole prescriptions will increase in the near future. However, the fatal concentration in blood is unclear at this time. Therefore, we report a fatal case involving ropinirole intoxication and discuss the fatal concentrations with reference to several autopsy cases involving ropinirole. Methods Ropinirole was quantified in femoral vein blood, cardiac blood, and urine from five autopsy cases in which ropinirole was detected by drug screening in our laboratory. One is a ropinirole intoxication case (this report) and the others were non-intoxication cases. Their ropinirole concentrations were compared and discussed. Results The ropinirole concentration in this case was 100 ng/mL in femoral blood, 160 ng/mL in cardiac blood, and 1840 ng/mL in urine. The ropinirole concentrations in the four non-ropinirole poisoning cases were 7–35 ng/mL (mean: 24 ng/mL) in femoral blood, 13–100 ng/mL (mean: 60 ng/mL) in cardiac blood, and 140–1090 ng/mL (mean: 640 ng/mL) in urine. Cardiac/peripheral ratios were in the range of 1.6–2.1 (mean 1.8). Conclusions There were no obvious signs of overdose, and the high cardiac/peripheral blood ratio suggested that postmortem redistribution may have occurred, but the peripheral blood ropinirole concentration (100 ng/mL) was obviously higher than that reported in the previous fatal case of ropinirole poisoning (64 ng/mL). Based on these results, the cause of death in this case was considered to be shock and fatal arrhythmia due to ropinirole poisoning. This case provides important data on postmortem blood and urinary levels of ropinirole poisoning.