Clin Psychopharmacol Neurosci.  2015 Aug;13(2):157-162. 10.9758/cpn.2015.13.2.157.

Effect of Adenine on Clozapine-induced Neutropenia in Patients with Schizophrenia: A Preliminary Study

  • 1Department of Psychiatry, Okehazama Hospital, Toyoake, Aichi, Japan.
  • 2Office of Clinical Pharmacy Practice and Health Care Management, Faculty of Pharmacy, Meijo University, Nagoya, Japan.


This study examined the utility of adenine for preventing clozapine-induced neutropenia.
This retrospective study examined the effect of adenine on clozapine-induced neutropenia in patients with treatment-resistant schizophrenia and was conducted at Okehazama Hospital in Japan from July 2010 to June 2013. Adenine was available for use from June 2011 onwards. Twenty-one patients started receiving clozapine treatment from July 2010 to April 2011 (the pre-adenine adoption group), and 47 patients started receiving it from May 2011 to June 2013 (the post-adenine adoption group). The effects of adenine were assessed based on changes in the patients' leukocyte counts and the frequency of treatment discontinuation due to clozapine-induced neutropenia.
Sixty-eight patients were treated with clozapine from July 2010 to June 2013. Of the 21 patients in the pre-adenine adoption group, 4 discontinued treatment due to clozapine-induced neutropenia, whereas only 2 of the 47 patients in the post-adenine adoption group discontinued treatment. The frequency of treatment discontinuation due to clozapine-induced neutropenia was significantly lower in post-adenine adoption group than in the pre-adenine adoption group (p=0.047).
Adenine decreased the frequency of treatment discontinuation due to clozapine-induced neutropenia. Our data suggest that combined treatment with clozapine and adenine is a safe and effective strategy against treatment-resistant schizophrenia.


Clozapine; Adenine; Neutropenia; Schizophrenia; Side-effect
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