Being extremely tired on not present in your mindset from anything, including but not limited to drugs & alcohol. When someone is wonked out, they resemble the mentality of a sterotypical zombie, with no cognative ability. When they are wonked out, they will not being able to think or practice reason, and are unlikely to remember any details of this experience later.
Likely to have stemmed from the expression zonked out, but has particular circumstances to help better describe these moments when they occur.
This can also include people who have passed out or are not awake if they got to this state from previous actions resulting in being wonked out prior to their sudden slumber.
I once worked 75 hours in a week on very little sleep, and was so wonked out by the final day I now need to work 75 more to make up for all my actions.
Jimmy finished his weekend alcohol supply by early saturday morning and was so wonked out we had to get him back to his home.