BLONANSERIN (BLN) DIFFERS FROM other atypical antipsychotic agents in that it binds selectively with only D2/D3 and 5-HT2A receptors.1 We report here three cases of schizophrenia improved by switching to blonanserin.

Case 1 was a 30-year-old male college student with paranoid schizophrenia, strong delusions of being observed, and auditory hallucinations. As an outpatient, he was initially prescribed 2 mg risperidone (RIS), which was increased over a 1-month period to 4 mg. However, auditory hallucinations were largely unchanged and maintaining concentration became difficult. A switch to 24 mg aripiprazole (ARP) showed little improvement, and we switched to BLN. As he could not attend classes or lead a normal daily life, 24 mg ARP was maintained and 8 mg BLN added. Auditory hallucinations almost completely disappeared, so ARP was tapered and discontinued. On only 16 mg BLN, the patient was able to attend classes over the next year without problems.

Case 2 was a 21-year-old man with paranoid schizophrenia who had presented 4 years earlier. Treated mainly with 15 mg/day of olanzapine (OLZ), he began to experience increased hallucinations and aggravation of other symptoms, such as tightness in the chest and anxiety. He was re-hospitalized and OLZ dosage was increased to 20 mg. This reduced auditory hallucinations slightly, but he had an onset of Parkinsonian symptoms, and sinus tachycardia adverse events led to higher levels of anxiety. Over the next 2 months, he was switched to 20 mg BLN. The psychotic symptoms disappeared and tachycardia improved. Slight drooling was quickly cleared up with 2 mg biperiden, which was continued after discharge.

Case 3 was a 44-year-old man with paranoid schizophrenia who had auditory hallucinations, paranoid delusions, hypersensitivity to sound and light, and delusions of being observed. The hallucinations and delusions were effectively treated with 4 mg RIS, but he suffered extreme drowsiness. After being switched to 16 mg BLN over a 1-month period, the drowsiness was alleviated, his psychotic symptoms disappeared, and he was discharged.

BLN could reduce auditory hallucinations when other medications had been ineffective. Compared to RIS, BLN has a stronger affinity for D2/D3 receptors,1,2 and this is likely why it can inhibit delusions and hallucinations. BLN was also effective for tachycardia, which was assumed to have been caused by muscarinic acetylcholine receptor M2 blockers and adrenergic α1 receptors (Case 2). Weak adrenergic α1 receptors and histamine H1 receptor blockers did not induce oversedation and lethargy, as is often seen with other medications (Case 3).

Taken together with the findings from tests in Korea,3 BLN has the potential to become the first-choice drug for schizophrenia, especially with predominantly positive symptoms, such as delusions and auditory hallucinations.


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  • 1
    Murasaki M. Preclinical characteristic and clinical positioning of blonanserin for schizophrenia. Jpn. J. Clin. Psychopharmacol. 2008; 11: 461476 (in Japanese).
  • 2
    Murasaki M, Nishikawa H, Ishibashi T. Dopamine-serotonin antagonist: receptor-binding profile of a novel antipsychotic blonanserin. Jpn. J. Clin. Psychopharmacol. 2008; 11: 845854 (in Japanese).
  • 3
    Yang J, Bahk WM, Cho HS et al. Efficacy and tolerability of blonanserin in the patients with schizophrenia: a randomized, double-blind, risperidone-compared trial. Clin. Neuropharmacol. 2010; 33: 169175.