Quetiapine and risperidone show equivalent efficacy for schizophrenia but quetiapine appears to be associated with a lesser degree of extrapyramidal symptoms
Quetiapine and risperidone have equivalent
efficacy for patients with schizophrenia exhibiting predominately
negative symptoms, but quetiapine has superior tolerability, especially
with respect to extrapyramidal symptoms, according to an article
in the January issue of the European Archives of Psychiatry and
Clinical Neuroscience.
The current study was a double-blind, randomized
study comparing efficacy and tolerability of the two atypical antipsychotics.
The study investigator, Michael Riedel, MD,
Ludwig-Maximilian-University Munich, Germany, commented: "One
of the key issues in treating patients with schizophrenia is achieving
a good quality of life by balancing efficacy and tolerability of
medication. Negative symptoms associated with schizophrenia are
less responsive to treatment. This small, but tightly controlled
pilot study shows that quetiapine and risperidone have the same
efficacy in patients with schizophrenia exhibiting mainly negative
symptoms, but only quetiapine shows a statistically significant
effect on treating alogia and affective blunting compared to baseline.
“Importantly there are significant differences
in the tolerability between both medications; quetiapine was superior
in many tolerability parameters including extrapyramidal symptoms.
To patients, a reduction in extrapyramidal symptoms really matters
in terms of quality of life. Medication with less extrapyramidal
symptoms therefore may help address patient compliance issues by
achieving the best balance of treatment efficacy and superior tolerability."
A total of 44 patients with schizophrenia
presenting with predominantly negative symptoms were randomized
to quetiapine (mean dose 589.7 mg/day) or risperidone (mean dose
4.9 mg/day) for a 12-week study period.
Efficacy was measured by the Positive and
Negative Syndrome Scale (PANSS) score (primary endpoint) and the
Scale for the Assessment of Negative Symptoms (SANS) and Clinical
Global Impression (CGI) rating scale. Tolerability was measured
using the Simpson-Angus Scale (SAS) and various laboratory measurements
Patients in both treatment groups showed significant improvements
in the PANSS (Positive and Negative Syndrome Scale) total, positive,
negative, and general psychopathology scores (P<0.01 compared
to baseline).
Patients in both treatment groups experienced
significant reduction in negative symptoms as early as week one
(P less than or equal to 0.01) and this improvement continued up
to week 12 (P less than or equal to 0.01 for all time points).
At week 12, both medications also achieved
significant improvements on some parameters of the Assessment of
Negative Symptoms (SANS) scale (quetiapine P<0.001 and risperidone
P<0.01 compared to baseline); however only quetiapine demonstrated
significant improvements in alogia and affective blunting compared
to baseline (both P<0.001).
Patients treated with quetiapine had a significantly
lower incidence of extrapyramidal symptoms, including akathisia
and parkinsonism compared to patients treated with risperidone (P=0.006).
In addition, more patients using risperidone required anticholinergic
medication to control such symptoms.
Quetiapine also resulted in decreased serum prolactin levels, while
risperidone increased prolactin levels, which has frequently been
associated with reduction in sexual drive and fertility.
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