Treatment response, safety, and tolerability of paliperidone extended release treatment in patients recently diagnosed with schizophrenia

A simple and rapid LC-MS/MS method for the simultaneous determination of eight antipsychotics in human serum, and its application to therapeutic drug monitoring

A simple and rapid liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed and used to determine eight antipsychotics (aripiprazole, clozapine, haloperidol, olanzapine, paliperidone, quetiapine, risperidone, and ziprasidone) in human serum for practical clinical usage. Stable isotope-labeled internal standards were used for all drugs to compensate for method variability, including matrix effects, ion extraction and ionization variations. Samples were prepared by simple protein precipitation with methanol. Chromatographic separation was accomplished in less than 3.3 min on a KINTEX C18 column (50 mm × 3.0 mm, 5 μm) using a gradient elution of 2 mM aqueous ammonium formate and methanol at a flow rate of 0.5 mL/min. Quantification was performed by multiple reaction monitoring (MRM) in the positive mode. The method was fully validated according to the latest recommendations of international guidelines. The correlation coefficients of calibration curves were all greater than 0.9945. Internal standard-normalized matrix effects ranged from 96.3% to 115%, and extraction recoveries were between 88.1% and 107%. Coefficients of variation ranged from 1.82 - 13.5% for intra-day precision, 5.69-14.7% for inter-day precision, and the relative error for accuracy did not exceed ± 13.5% for any analyte. The method was successfully applied to routine clinical therapeutic drug monitoring for 2,173 samples.

Long-lasting extrapyramidal symptoms after multiple injections of paliperidone palmitate to treat schizophrenia

PURPOSE

Antipsychotic drug treatment can potentially lead to adverse events such as extrapyramidal symptoms (EPSs). If these events persist, they lower patient quality of life. The purpose of this report is to present our experience with such a case, as an example to encourage further study.

PATIENTS AND METHODS

The patient was a 64-year-old male who had been diagnosed with schizophrenia that had been treated with oral antipsychotics for over 40 years. Due to lack of compliance, he was treated with the long-acting injectable antipsychotic, paliperidone palmitate, but developed persistent EPSs after 6 months. He was subsequently treated and monitored in our inpatient facility.

RESULTS

Antipsychotic treatment was stopped. After 6 weeks, the patient's psychosis had worsened, but his EPSs remained unchanged. Levodopa treatment was then started (up to 400 mg/d), which improved his EPSs, so he was restarted on oral antipsychotic therapy (aripiprazole, 6-18 mg/d). His psychotic symptoms improved over 2 months. The improvements in both psychosis and EPSs remained stable. Dopamine transporter scans revealed moderate dopamine transporter loss in the striatum, and computed tomography revealed no sign of brain abnormalities, suggesting that the patient was susceptible to dopamine reductions.

CONCLUSION

Paliperidone palmitate can induce EPSs, even if injected only a few times. Although the characteristics of the drug are potential causes, the patient's predisposition to dopamine perturbations can also influence the outcome. Therefore, adequate awareness is required before injection.