Post authorization safety study comparing quetiapine to risperidone and olanzapine.

Area of Science:

• Pharmacovigilance
• Comparative Effectiveness Research
• Antipsychotic Drug Safety

Background:

• Second-generation antipsychotics (SGAs) like quetiapine, olanzapine, and risperidone are widely prescribed.
• Understanding the comparative safety profiles of these agents is crucial for clinical decision-making.
• Previous studies have suggested varying adverse event profiles among SGAs.

Purpose of the Study:

• To compare the rates of specific adverse outcomes in patients initiating quetiapine, olanzapine, or risperidone.
• To provide real-world evidence on the comparative safety of these commonly used antipsychotics.

Main Methods:

• An observational study utilizing the PHARMO Database Network in the Netherlands.
• Inclusion of patients initiating quetiapine (n=4658), olanzapine (n=5856), or risperidone (n=7229) between 2000-2009.
• Comparison of rates for all-cause mortality, suicide attempt failures, extrapyramidal symptoms (EPS), diabetes mellitus (DM), hypothyroidism, and acute myocardial infarction (AMI).

Main Results:

• Quetiapine was associated with significantly lower EPS rates compared to both risperidone (HR 0.18) and olanzapine (HR 0.59).
• Quetiapine showed a higher rate of failed suicide attempts compared to risperidone (HR 2.07).
• Quetiapine was also linked to lower diabetes mellitus (DM) rates compared to olanzapine (HR 0.66).

Conclusions:

• Quetiapine demonstrated a favorable profile regarding EPS and DM compared to risperidone and olanzapine, respectively.
• However, quetiapine use was associated with an increased risk of failed suicide attempts compared to risperidone.
• Study findings should be interpreted cautiously due to potential channelling and residual confounding.