Death following an intramuscular injection of paliperidone: A case report

Abstract

Summary Paliperidone (9-hydroxyrisperidone), the primary active metabolite of risperidone, is a benzisoxazole derivative of the second-generation antipsychotics. Paliperidone palmitate or PP (the palmitate ester of paliperidone) is available as a once-daily oral tablet, a once-monthly injection or PP1M, and a 3-monthly injection or PP3M (marketed under the name of Trevicta® in the European Union). Despite the recent availability of PP3M, several cases of intoxication have been reported worldwide, including lethal cases. However, in Europe, no case of fatal poising has been reported to date. A 33-year-old man was found dead in his room at his parents’ home. His only medical background was a history of schizophrenia. The external examination was without any particularity except a runny nose of brownish liquid with an alcoholic smell. Given the context and the lack of evidence of a third party intervention, an autopsy was not considered necessary. Toxicological analysis of right femoral blood highlighted the presence of paliperidone (240 μg/L) only. The risk associated with the use of PP3M formulation is still imperfectly evaluated and several cases of intoxication have been reported worldwide, including fatal cases. In this case, paliperidone poisoning appears to be the highly likely cause of death. In fact, the blood concentration of paliperidone is high, twice the toxicity threshold used in therapeutic monitoring, and no other substances have been identified. This case highlights: the necessity to always evaluate the benefit-risk balance when prescribing this sustained-release form of paliperidone and the difficulties in interpreting paliperidone concentration in forensic cases.