ZypAdhera ® (olanzapine pamoate monohydrate)

This information is intended for UK registered healthcare professionals only as a scientific exchange in response to your search for information. Please refer to the link for full prescribing information: ZypAdhera Summary of Product Characteristics (SmPC)

ZypAdhera® (olanzapine pamoate): Onset of Post Injection Syndrome

In most cases, initial signs and symptoms appeared within 1 hour following injection. Reactions occurred rarely (<1 in 1,000 injections) between 1 and 3 hours, and very rarely (<1 in 10,000 injections) after 3 hours.

Further Information from Clinical Studies

Onset in Clinical studies

The mean time to onset of symptoms for a post-injection syndrome event was 49 minutes (median, 25 minutes; range, 0-300 minutes), with 80% occurring within 1 hour post-injection.1

Time to incapacitation was defined as the presence of clinically significant disorientation, ataxia, or sedation, such that the patient would not have been able to seek assistance on his own. Of the 22 cases that met criteria for incapacitation, 21 cases contained enough information to determine when the patient was first observed in an incapacitated state. The time to incapacitation post-injection was a mean of 75 minutes (median, 60 minutes; range, 10-300 minutes).1 

Of the 30 total cases, 23 (77%) were hospitalized. The mean time to hospitalization was 178 minutes (median, 150 minutes; range, 50 to 420 minutes).1

Post-injection syndrome events have not been characterized by a sudden onset of incapacitation, but usually began with milder symptoms that progressed in number and/or severity. The duration of the post-injection event varied from 1.5 to 72 hours.1

Description of Data Set

An analysis of post-injection syndrome cases from 8 Lilly premarketing clinical trials (August 2000 through October 2008) in patients aged 18 to 75 years with schizophrenia or schizoaffective disorder receiving olanzapine LAI (mean exposure, 14 months; range, 2 weeks to 3.8 years) therapy was conducted.1 

Depending on the specific study, olanzapine LAI doses ranged from 45 to 405 mg, and injection intervals could be of 2, 3, or 4 weeks. Injections given at 2-week intervals could not exceed a dose of 300 mg.1

Events occurred at various olanzapine LAI doses, cumulative exposure lengths, and injection numbers.1

Update on Cases through August 30, 2019

Time to onset was reported to be within the first hour post-injection in 874/1097 (79.7%) postmarketing study and spontaneous cases through August 30, 2019, between 1 and 2 hours post-injection in 60 cases, between 2 and 3 hours post-injection in 32 cases, unspecified but reported as <3 hours in 5 cases, and unknown in 120 cases. Six spontaneous cases occurred after 3 hours.2


1. Detke HC, McDonnell DP, Brunner E, et al. Post-injection delirium/sedation syndrome in patients with schizophrenia treated with olanzapine long acting injection, I: analysis of cases. BMC Psychiatry. 2010;10(1):43. http://dx.doi.org/10.1186/1471-244X-10-43

2. Data on file, Eli Lilly and Company and/or one of its subsidiaries.


LAI = Long Acting Injection = olanzapine pamoate

Date of Last Review: December 12, 2019

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