Why does zyprexa (olanzapine) relprevv have to given in the butt?

Zyprexa (olanzapine) Relprevv. Is an injection designed to release slowly into the blood stream over a 4 week period. As such, it is designed to be given deep intramuscularly. Your bicps, where most other injections are given, are not big enough.
Zyprexa (olanzapine) relprevv. Thigh muscle is larger & is more suitable for deep intramuscular injections.
For safety. This was how the medication was standardized and approved by the fda. Absorption rates can differ based on the muscle and the vascular supply to the muscle. Ideally with relprevv due to the 7/10000 rate of pdss the injection is provided in large muscle.