Add-on Cariprazine in patients with long-term clozapine treatment and treatment resistant schizophrenia: Two cases of psychotic deterioration and Pisa Syndrome
Judith Weise 1, Georg Schomerus 1, Sven Speerforck 1*
Department of Psychiatry and Psychotherapy, University of Leipzig, Leipzig, Germany
Received: June 9, 2021; Revised: August 25, 2021; Accepted: September 11, 2021; Published online: September 11, 2021.
© The Korean College of Neuropsychopharmacology. All rights reserved.

An increasing number of studies deal with medical options for treatment resistant schizophrenia. If no remission can be achieved with clozapine, a combination of antipsychotics can be considered. The combination of clozapine and cariprazine is rarely studied. Cariprazine is a partial agonist on dopamine D2 and D3 receptors and a pharmaceutically rational add-on to clozapine. Stimulating D3 receptors has been linked to improved cognition and mood, with negligible extrapyramidal side effects. We present two patients with long-term treatment resistant schizophrenia receiving cariprazine and clozapine. Whereas psychotic symptoms worsened, the patients developed extrapyramidal side effects with a Pisa syndrome. The syndrome remitted after discontinuation of cariprazine. Possible explanations by pharmacodynamic interactions and drug specific receptor profiles are discussed.
Keywords: cariprazine, clozapine, treatment resistance, schizophrenia, Pisa syndrome