Abstract: Objective To investigate the patterns of adverse drug reactions (ADRs) associated with olanzapine, and to provide a reference for rational clinical drug use. Methods ADR reports related to olanzapine and collected in 2021-2025 were retrieved from the spontaneous reporting system database of The Second Affiliated Hospital of Henan Medical University. The basic data, demographics of patients, medications, system-organ classes involved and clinical manifestations were analyzed. Results A total of 243 reports on ADRs of olanzapine were included, 32.10% of which (78/243) were classified as “new/serious.” The most common systems involved were the nervous system (37.45%), hepatobiliary system (15.64%), cardiovascular system (15.64%), hematological system (11.52%), and gastrointestinal system (5.76%). Conclusion The ADRs of olanzapine can involve multiple systems and organs. Damage to the nervous system is the most common. Most of these ADRs occur at conventional doses of 5 mg·d^-1 and 10 mg·d^-1. Olanzapine is likely to induce a marked increase in transaminase levels in early treatment, and female patients are more susceptible to hematologic system damage. The safety of olanzapine needs to be monitored in clinical practice, especially in terms of liver function and routine blood tests.

Key words: Olanzapine, Hematological System Damage, Hepatobiliary System Damage, Cardiovascular System Damage, Nervous System Damage, Adverse Drug Reactions