The following is a summary of the “Long-acting injectable paliperidone palmitate induced severe cutaneous allergic reaction in a patient with first episode delusional disorder tolerating oral paliperidone regimen: a case report” published in the November 2022 issue of Psychiatry by Borojevic et al.

Paliperidone is an effective second-generation antipsychotic medicine that is used for the treatment of schizophrenia and schizoaffective disorder, as well as for the management of bipolar and depressive episodes when combined with mood stabilizers and antidepressants. Paliperidone may be administered either orally or intravenously. An unanticipated episode of cutaneous allergic reaction was provoked by paliperidone long-acting injectable (LAI) following oral tolerance, and the researchers publish their findings here.

Paliperidone pills with tolerance were administered to a 55-year-old male patient who was diagnosed with first episode delusional disorder. On day 7, following administration of paliperidone LAI, he had an acute and severe allergic reaction, which included face flushing, widespread urticaria, and some moderate airway tightness. Within a few minutes of receiving the antihistamine injection, the allergy symptoms were alleviated.

It is likely that the excipients in the formulation of the LAI, rather than paliperidone itself, were responsible for the allergic reaction that occurred following administration of the LAI, but not the oral tablets. The allergic reaction did not occur after administration of the oral tablets. This case demonstrates how important it is to keep an eye out for allergic responses in mental patients as they are transitioning from the oral to the LAI version of paliperidone.