Department of Social Psychiatry, National Institute of Mental Health, National Center of Neurology and Psychiatry, Tokyo, Japan.
Psychiatry Clin Neurosci. 2013 Jul;67(5):345-51. doi: 10.1111/pcn.12056. Epub 2013 May 28.
It has been recommended that for patients with schizophrenia, antipsychotics should be prescribed simply, using an optimal dose. However, pro re nata (p.r.n., meaning to use on an as-needed basis) antipsychotics may increase the risk of excessive dosing (defined as mean chlorpromazine-equivalent doses above 1000 mg) and polypharmacy (combination use of different antipsychotics). This study aimed to investigate the increased risk caused by p.r.n. antipsychotics.
The subjects included 413 patients with schizophrenia from 17 acute psychiatric wards in nine hospitals. Over a 24-h period on a survey day, data on regular medication and the use of p.r.n. were collected. The analysis focused on p.r.n. antipsychotics in agitated patients. We used McNemar's test to evaluate differences in the proportions of patients prescribed antipsychotics with excessive dosing or polypharmacy before (i.e., regular medication only) and after prescribed p.r.n. antipsychotics were added to regular medication (i.e., regular medication plus p.r.n. antipsychotics).
Of 413 patients, 312 (75.5%) were prescribed p.r.n. for agitated status. Of those, 281 (90.1%) were prescribed p.r.n. antipsychotics. The total doses were significantly higher and more compounded in case patients prescribed p.r.n. antipsychotics than in those who were not. Seventeen patients (4.1%) were actually administered p.r.n. antipsychotics. Their total medication, including p.r.n. on the current day, represented excessive dosing or polypharmacy of antipsychotics.
The use of p.r.n. antipsychotics may cause hidden excessive dosing and polypharmacy. Our results indicate the importance of careful monitoring of p.r.n. antipsychotics to agitated patients with schizophrenia.
对于精神分裂症患者，建议简单地开处方，使用最佳剂量的抗精神病药物。然而，需要时（prn，按需使用的意思）给予的抗精神病药物可能会增加过度给药（定义为平均氯丙嗪等效剂量超过 1000mg）和联合用药（使用不同的抗精神病药物联合治疗）的风险。本研究旨在探讨 prn 抗精神病药物引起的风险增加。
研究对象为来自 9 家医院 17 个急性精神科病房的 413 例精神分裂症患者。在调查日的 24 小时内，收集常规药物和 prn 使用的数据。分析重点是激动患者的 prn 抗精神病药物。我们使用 McNemar 检验评估在未使用（即仅常规药物）和使用 prn 抗精神病药物后（即常规药物加 prn 抗精神病药物），患者被处方过度给药或联合用药的比例差异。
在 413 例患者中，312 例（75.5%）因激动状态而开具了 prn 药物。其中，281 例（90.1%）开具了 prn 抗精神病药物。与未开具 prn 抗精神病药物的患者相比，开具 prn 抗精神病药物的患者的总剂量显著更高，且更复杂。17 例患者（4.1%）实际上接受了 prn 抗精神病药物治疗。他们当天包括 prn 的总用药量代表了抗精神病药物的过度给药或联合用药。
使用 prn 抗精神病药物可能导致隐藏的过度给药和联合用药。我们的结果表明，对于患有精神分裂症且激动的患者，谨慎监测 prn 抗精神病药物非常重要。
