Effects of olanzapine and clozapine upon pulse rate variability

Michael Mueck-Weymann, Thomas Rechlin, Franz Ehrengut, Robert Rauh, Jens Acker, Ralf W. Dittmann, Jörg Czekalla, Peter Joraschky, Dominique Musselman

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


Based upon their in vitro receptor binding profiles, the atypical antipsychotics clozapine and olanzapine exhibit cholinergic receptor binding of similar potency. Data comparing the in vivo anticholinergic effects, however, of these neuroleptics upon neurocardiac control are sparse. The goal of this study was to compare the in vivo effects of clozapine and olanzapine upon neurocardiac control by assessment of the pulse rate variability (PRV) in schizophrenic patients and healthy controls. Twenty patients with schizophrenia (according to DSM-III-R criteria) treated with either clozapine (100-600 mg/day) or olanzapine (10-20 mg/day), and ten healthy controls, were recruited into the study. PRV was assessed by continuously recording the skin blood volume in the fingertip of the second digit under resting conditions and PRV parameters were calculated. When significant differences in PRV parameters between the patients and controls were detected by Kruskal-Wallis tests, Mann-Whitney tests were used to test for group differences between the olanzapine- and clozapine-treated patients. In comparison to the healthy controls, the PRV parameters of the clozapine- and olanzapine-treated schizophrenic patients were significantly reduced. Indeed the reduction of PRV was significantly greater in the clozapine-treated group compared to the olanzapine-treated group (P<0.05). Compared to the controls, only the clozapine-treated patients showed a significantly diminished low-frequency (LF)/high frequency (HF)-ratio, a PRV parameter reflecting sympatho-vagal balance. The significantly greater reductions in PRV parameters of the clozapine-treated compared to olanzapine-treated patients may be caused by clozapine's higher affinity for α1-adrenergic receptors in vivo compared with olanzapine. The similar LF/HF ratios of the healthy controls and olanzapine-treated patients suggests that the sympathetic-parasympathetic modulation of PRV remains relatively unchanged even during olanzapine treatment.

Original languageEnglish (US)
Pages (from-to)93-99
Number of pages7
JournalDepression and anxiety
Issue number3
StatePublished - 2002
Externally publishedYes


  • Atypical antipsychotics
  • Autonomic neuropathy
  • Clozapine
  • Heart rate variability
  • Neurocardiac control
  • Olanzapine
  • Pulse rate variability

ASJC Scopus subject areas

  • Psychiatry and Mental health


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