From the Guidelines
The administration of combined high-dose antipsychotic therapy to an autistic patient with contraindications is potentially life-threatening.
Key Risks and Considerations
- The use of high-dose antipsychotics, such as haloperidol and olanzapine, in combination, poses significant health risks, including neuroleptic malignant syndrome, a potentially life-threatening condition 1.
- QTc prolongation, a condition that can lead to dysrhythmias such as torsades de pointes, is a feared cardiac adverse effect of antipsychotics, and the risk is increased with coadministration of other medications 1.
- The combination and dosing regimen employed may lead to severe and potentially life-threatening complications, including cardiac adverse effects, neurologic adverse effects, and metabolic adverse effects 1.
- Antipsychotic polypharmacy may be associated with a higher risk of adverse effects, including extrapyramidal symptoms, weight gain, and metabolic changes 1.
Recommendations
- Monotherapy should be strived for with most patients, as it generally incurs less health service costs and gives a lower overall risk for adverse effects 1.
- Clozapine monotherapy is underutilized and should be considered for a wider spectrum of patients than it is currently used for 1.
- Pharmacogenetics may offer a fast and cost-effective method to determine better optimized treatment approaches in the future 1.
- Patients on antipsychotic polypharmacy should be closely monitored for adverse effects and considered for switching to monotherapy if possible 1.
From the FDA Drug Label
5.16 Use in Combination with Fluoxetine, Lithium, or Valproate
When using olanzapine and fluoxetine in combination, also refer to the Boxed Warning section of the package insert for Symbyax.
Warning: Increased Mortality in Elderly Patients with Dementia-Related Psychosis
5.3 Neuroleptic Malignant Syndrome (NMS)
5.9 Leukopenia, Neutropenia, and Agranulocytosis
The use of combined high-dose antipsychotic therapy, including olanzapine, in an autistic patient with contraindications may be potentially life-threatening due to the increased risk of adverse reactions such as:
- Neuroleptic Malignant Syndrome (NMS)
- Leukopenia, Neutropenia, and Agranulocytosis However, the label does not directly address the use of high-dose antipsychotic therapy in autistic patients. 2