CASE

A 42-year-old female with schizophrenia, nonadherent to previously prescribed medication was admitted to our acute psychiatric department. She experienced positive symptoms (paranoid delusions), as well as disorganized thinking and behavior. Oral risperidone 4 mg two times a day was recommenced and titrated with mild improvement in her psychotic symptoms with the idea of switching to paliperidone LAI and eventually ceasing oral medication. Oral paliperidone was unavailable for prescription due to local restrictions. At admission her routine laboratory tests showed no abnormalities, but 5 days after receiving paliperidone LAI, routine laboratory tests showed a strong decrease in her WBC and absolute neutrophilic and lymphocytic count ( Lkc 2.89x109/L, Neut 1.57x 109/L, Lym 0.88x 109 /L ). Antipsychotic-induced blood dyscrasia was suspected and paliperidone depot was discontinued. The patient had rapid improvement in her WBC reaching the reference range in 10 days ( Lkc 4.23 x 109/L, Neut 2.51x10 9/L, Lym 0.98x 109/L). Sertindole was introduced consdering her history of a good therapeutic response to the drug, with improvement in psychotic symptoms. She is currently stable taking sertindole 16 mg/day, clonazepam 2 mg/day and alprazolam 0.5 mg/day.

DISCUSSION

The onset of neutropenia and lymphopenia post-paliperidone LAI initiation, resolving in 10 days,, indicate a direct association. Few cases report to date describe paliperidone-induced leukocytopenia, with rapid recovery post-discontinuation. Proposed mechanisms include bone marrow suppression and peripheral WBC destruction. It has been proposed that drug-induced neutropenia is often dose-dependent, which could explain why our patient exhibited tolerability to risperidone but developed cytopenia upon transitioning to depot paliperidone.