What do you do for patients who have received accidental extra dosages of long-acting injectable antipsychotics?  

It depends on what kind of long-acting injection. Most antipsychotics, except Zyprexa Relprevv, would only require close monitoring for side effects (like dystonia, muscle twitches, and muscle spasms). I would encourage getting an EKG to check for any QTc prolongation. If there are any signs of side...

In addition, the patient needs to be made aware of what side effects may occur, and perhaps a guardian or parent or group home, so that they can receive appropriate follow-up to address symptom relief.

Close monitoring, any EPS, one repeat EKG in a few days, reporting this to the family so that they are aware of the patient getting an extra dose, and cutting down or stopping any oral anti-psychotics to mitigate risk are some of the things I would do. There is no clear protocol on this, unfortunate...