From the Guidelines
Olanzapine is classified as a second-generation atypical antipsychotic medication, and its use is associated with significant side effects, including metabolic effects such as weight gain, hyperglycemia, and increased risk of diabetes, as well as sedation, drowsiness, and orthostatic hypotension. The medication is primarily used to treat schizophrenia, bipolar disorder, and treatment-resistant depression. According to the most recent evidence 1, olanzapine requires greater monitoring due to its increased risk of type 2 diabetes. Common side effects of olanzapine include:
- Significant weight gain
- Increased appetite
- Sedation
- Drowsiness
- Metabolic side effects, such as hyperglycemia, increased risk of diabetes, elevated cholesterol, and triglycerides
- Dry mouth
- Constipation
- Dizziness
- Orthostatic hypotension More serious side effects include extrapyramidal symptoms, tardive dyskinesia with long-term use, and neuroleptic malignant syndrome in rare cases. Olanzapine carries a black box warning regarding increased mortality risk in elderly patients with dementia-related psychosis. The medication works primarily by blocking dopamine D2 receptors and serotonin 5-HT2A receptors in the brain, which helps regulate neurotransmitter activity that contributes to psychotic symptoms. Regular monitoring of weight, blood glucose, lipid profiles, and movement disorders is essential for patients taking olanzapine to manage these potential side effects, as recommended by the 2024 standards of care in diabetes 1.
From the FDA Drug Label
Dystonic events, Parkinsonism events, Akathisia events, Dyskinetic events, and Nonspecific events are categories of extrapyramidal symptoms as defined in MedDRA version 12. The following table enumerates the percentage of patients with treatment-emergent extrapyramidal symptoms as assessed by categorical analyses of formal rating scales during controlled clinical trials comparing fixed doses of intramuscular olanzapine for injection with placebo in agitation. Symptoms of dystonia, prolonged abnormal contractions of muscle groups, may occur in susceptible individuals during the first few days of treatment Dystonic symptoms include: spasm of the neck muscles, sometimes progressing to tightness of the throat, swallowing difficulty, difficulty breathing, and/or protrusion of the tongue. Other Adverse Reactions Observed During the Clinical Trial Evaluation of Oral Olanzapine Reactions are classified by body system using the following definitions: frequent adverse reactions are those occurring in at least 1/100 patients; infrequent adverse reactions are those occurring in 1/100 to 1/1000 patients; rare reactions are those occurring in fewer than 1/1000 patients
The classification of Olanzapine is an atypical antipsychotic. The side effects of Olanzapine include:
- Extrapyramidal symptoms such as:
- Dystonic events
- Parkinsonism events
- Akathisia events
- Dyskinetic events
- Other adverse reactions such as:
- Infrequent: chills, face edema, photosensitivity reaction, suicide attempt
- Rare: chills and fever, hangover effect, sudden death
- Cardiovascular System: Infrequent: cerebrovascular accident, vasodilatation
- Digestive System: Infrequent: abdominal distension, nausea and vomiting, tongue edema
- Hemic and Lymphatic System: Infrequent: thrombocytopenia
- Metabolic and Nutritional Disorders: Frequent: alkaline phosphatase increased
- Musculoskeletal System: Rare: osteoporosis
- Nervous System: Infrequent: ataxia, dysarthria, libido decreased, stupor
- Respiratory System: Infrequent: epistaxis
- Skin and Appendages: Infrequent: alopecia
- Special Senses: Infrequent: abnormality of accommodation, dry eyes
- Urogenital System: Infrequent: amenorrhea, breast pain, decreased menstruation, impotence 2
From the Research
Classification of Olanzapine
- Olanzapine is classified as a second-generation (atypical) antipsychotic agent 3, 4
- It is a thienobenzodiazepine derivative with proven efficacy against the positive and negative symptoms of schizophrenia 3
Side Effects of Olanzapine
- Common adverse effects reported with olanzapine include:
- Olanzapine is associated with significantly fewer extrapyramidal symptoms than haloperidol and risperidone 3, 5
- In adolescents, olanzapine is likely to cause greater increases in bodyweight, sedation, blood lipids, serum prolactin, and liver transaminase levels compared to adults 6
Comparison with Other Antipsychotics
- Olanzapine has been compared to other antipsychotics, including haloperidol, risperidone, and clozapine, in various studies 3, 5, 7
- Olanzapine has been shown to have superior antipsychotic efficacy compared to haloperidol in the treatment of acute phase schizophrenia 3
- Olanzapine may cause fewer extrapyramidal side effects than risperidone, but more weight gain 5