For how long after anaphylactic shock can we expect after effects & what are they?

1-2 days: Depending on the severity of the reaction, a person can feel drained for a day or 2 after their reaction. Ample rest should be enough and hydration.

1-2 days: Developing anaphylactic reactions involves many organs, depending how severe the reaction was. If it was treated as out patient and did not need intubation, usually a few hours to a day the person feels tired. If the person was ill enough to be intubated and admitted to the hospital, the time to resuscitation is key for brain preservation. So it is variable.