統合失調症における長時間作用型パリペリドンパルミテートによる遷延性遅発性ジスキネジアの誘発：症例報告

BACKGROUND Tardive dyskinesia is an iatrogenic syndrome that can include dystonia, akathisia, facial tics, chorea, and other abnormal involuntary movements. Tardive dyskinesia follows antipsychotic medication and results from the antagonism of dopamine receptors. This report describes a 40-year-old woman with schizophrenia treated with the long-acting antipsychotic paliperidone palmitate, with persistent tardive dyskinesia, requiring long-term management. CASE REPORT A 40-year-old woman with schizophrenia was administered long-acting paliperidone palmitate for 1 month in April 2017 and then switched to long-acting paliperidone palmitate for 3 months starting in October 2017. After 3 months of long-acting injection exposure (April 2018), she developed sustained cervical posturing and mask-like facies. Dose reduction to 350 mg was ineffective; the long-acting injection was stopped in June 2019, and aripiprazole 10 mg/day was started. Adjuncts (trihexyphenidyl, amantadine, and intermittent benzodiazepines) provided only limited benefit. Clozapine was started in December 2019 and titrated, with gradual, incomplete improvement. On readmission in May 2024, Neurology diagnosed tardive dyskinesia, particularly tardive dystonia. Over 6 years without vesicular monoamine transporter 2 (VMAT-2) inhibitors, her dystonia lessened but persisted, and she was discharged on clozapine and fluvoxamine. CONCLUSIONS Tardive dystonia can follow exposure to long-acting injectable paliperidone and may be prolonged yet partly reversible despite discontinuation. Given therapeutic limits, variable prognosis, and the 3-month formulation's extended pharmacokinetics, clinicians should maintain high suspicion, minimize dopamine-receptor-blocking exposure, and individualize care, considering timely VMAT-2 inhibitors or clozapine, plus structured long-term motor monitoring and shared decision-making. This report highlights the presentation of tardive dyskinesia as a complication of antipsychotic medication and the approach to management of this iatrogenic syndrome.