Technically you could try to use an adenosine agonist for this, as caffeine is an antagonist ... this would make you at least very drowsy of course for the time while it is active. I'm curious though why adenosine agonists or reuptake inhibitors are so relatively unknown - some specific benzodiazepines and barbiturates are AdRIs, and the benzo antagonist flumazenil is one too (which could be the reason that it can be used clinically, if it was like naloxone for opioids [okay, this one is an inverse agonist, so not the best example, but slow infusion of flumazenil is a standard procedure for benzo w/d in some countries and appears to be superior to cold turkey], it would instantly induce severe, maybe life treatening seizures- or?) ... so adenosinergics could be very useful for drug withdrawal..