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Clozapine-induced weight loss?

Francisco Appiani, MD

Universidad de Buenos Aires, Facultad de Medicina, Asociación Civil para el Estudio y Desarrollo de las Neurociencias (ACEDEN), Buenos Aires, Argentina

Brendan T. Carroll, MD

University of Cincinnati College of Medicine, Chillicothe, OH, USA

Camilo Muñoz, MD

Santa Rosa Hospital, La Pampa, Argentina, Asociación Civil para el Estudio y Desarrollo de las Neurociencias (ACEDEN), Buenos Aries, Argentina

Juan Trecco, MD

Trenque Lauquen, Asociación Civil para el Estudio y Desarrollo de las Neurociencias (ACEDEN), Buenos Aires, Argentina

KEYWORDS: clozapine, weight loss, schizophrenia


Olanzapine and clozapine are known for their capacity to produce metabolic syndrome through weight gain. Moreover, in a meta-analysis about atypical antipsychotic-induced weight gain reported by Allison et al, therapy with clozapine and olanzapine was associated with an average increase in body weight of 9.9 lb and 9.2 lb, respectively within 10 weeks of continued treatment.1,2

This letter presents the case of a schizophrenia patient, age 32, who was treated with olanzapine for 4 years. The dose range was between 10 to 20 mg/d (according to his clinical state) because the patient remained with residual positive and negative symptoms. With this pharmacological regimen the patient had a body weight increase of 44 lbs (from 184.5 to 228.5 lbs). Because of an acute relapse, we decided to replace olanzapine with clozapine. This drug was titrated up to 300 mg/d and with this change the patient stabilized, was without residual symptoms, and within 1 year of clozapine treatment his body weight decreased 30.5 lbs (from 228.5 to 198 lbs).

In this patient, despite clozapine’s tendency to increase body weight, the favorable clinical outcome achieved with this drug (especially the reduction of negatives symptoms) made it possible to adhere to a diet and exercise regimen.

DISCLOSURES: The authors report no financial relationships with any company whose products are mentioned in this article or with manufacturers of competing products.


  1. Allison DB, Mentore JL, Heo M, et al. Antipsychotic-induced weight gain: a comprehensive research synthesis. Am J Psychiatry. 1999;156:1686–1696.
  2. Nasrallah HA, Newcomer JW. Atypical antipsychotics and metabolic dysregulation evaluating the risk/benefit equation and improving the standard of care. J Clin Psychopharmacol. 2004;24:S7–S14.
  3. Hanwella R, de Silva V, Wijeratne C, et al. Clozapine-associated weight loss. J Psychopharmacol. 2009;24:1127–1129.

CORRESPONDENCE: Brendan T. Carroll, MD, University of Cincinnati, The Neurosciences Alliance, 330 Taylor Blair Road, West Jefferson, OH 43162 USA, E-MAIL: