The recently released information about the toxic effect of the FAAH inhibitor BIA-10-2474 clearly indicates that there were no symptoms of toxicity observed up to 20 mg single dose in all subjects. The first symptoms of toxicity were detected when the the subjects received the next dose of 50 mg. It remains unclear how long the substance remains in the tissue and whether accumulation might have contributed to the toxicity. However, since they waited 19 days between the last cohort dosage and the next, this is unlikely. Therefore, a single dose of 50 mg of this compound is neurotoxic, again pointing towards non-FAAH mediated adverse effects.