Fitton A, Benfield P
Adis International Limited, Auckland, New Zealand.
Pharmacoeconomics. 1993 Aug;4(2):131-56. doi: 10.2165/00019053-199304020-00007.
Clozapine, an antipsychotic agent with relatively weak central antidopaminergic activity, displays atypical pharmacological and clinical properties vis-a-vis the classic antipsychotics. Thus, clozapine is effective against both the positive and negative symptoms of schizophrenia and has a low propensity to cause extrapyramidal effects. Furthermore, clozapine is effective in a substantial proportion (up to 60%) of patients who are refractory to or intolerant of standard antipsychotic therapy. Despite its promising therapeutic potential, the relatively high incidence of clozapine-induced agranulocytosis (approximately 1% of patients) and the associated need for regular haematological monitoring currently restricts the drug's use to the treatment of chronic and severe schizophrenia refractory to standard antipsychotic therapy, and to those patients unable to tolerate such therapy. In the US, the current wholesale price of clozapine (exclusive of monitoring) is $US2.85 per 100mg tablet, amounting to $US4160 annually (1992 dollars) at the most commonly prescribed dose of 400 mg/day ($US2.40 per tablet and $US3510 annually to state programmes through Medicaid reimbursement legislation). In the UK, the annual cost of clozapine (at the average dose of 300 mg/day), inclusive of blood monitoring, is 1806 British pounds sterling (1992 pounds). Although the acquisition cost of clozapine is high in comparison with that of standard antipsychotics, preliminary cost-effectiveness estimates in patients with treatment-resistant schizophrenia suggest that the clinical benefits of the drug (viz. improved psychopathology, social functioning and quality of life) may confer medium to long term economic benefits, primarily by reducing the need for psychiatric hospital services. This effect is most likely to be seen on long term ( greater than or equal to 2 years) maintenance therapy with clozapine. Savings in hospital costs are, however, likely to be offset, at least initially, by increased reliance on outpatient services, and clozapine may therefore confer additional economic costs during the first year or so of treatment. In the longer term, however, the initial cost investment may be recouped in the form of savings to psychiatric institutions and insurers.
氯氮平是一种中枢抗多巴胺能活性相对较弱的抗精神病药物，与经典抗精神病药物相比，具有非典型的药理和临床特性。因此，氯氮平对精神分裂症的阳性和阴性症状均有效，且引起锥体外系反应的倾向较低。此外，相当一部分（高达60%）对标准抗精神病治疗无效或不耐受的患者使用氯氮平有效。尽管氯氮平具有潜在的治疗前景，但氯氮平引起粒细胞缺乏症的发生率相对较高（约1%的患者），以及相关的定期血液学监测需求，目前限制了该药物仅用于治疗对标准抗精神病治疗无效的慢性重度精神分裂症，以及那些无法耐受此类治疗的患者。在美国，氯氮平目前的批发价（不包括监测费用）为每100mg片剂2.85美元，以最常用的每日400mg剂量计算，每年高达4160美元（1992年美元）（每片2.40美元，通过医疗补助报销立法，每年给各州项目3510美元）。在英国，氯氮平的年度费用（平均每日剂量300mg），包括血液监测，为1806英镑（1992英镑）。尽管与标准抗精神病药物相比，氯氮平的购置成本较高，但对难治性精神分裂症患者的初步成本效益估计表明，该药物的临床益处（即改善精神病理学、社会功能和生活质量）可能带来中长期经济效益，主要是通过减少对精神病院服务的需求。这种效果最有可能在氯氮平的长期（大于或等于2年）维持治疗中显现。然而，至少在最初阶段，住院费用的节省可能会被对门诊服务的更多依赖所抵消，因此氯氮平在治疗的第一年左右可能会带来额外的经济成本。然而，从长远来看，最初的成本投入可能会以节省精神病院和保险公司费用的形式收回。
