I was thinking more in terms of actual antidote by either binding the active substance or speeding up its metabolism, rather than having two substances acting in opposing directions.

Anyway, I gave up caffeine earlier this year and am quite happy with the results. Steady and calm energy, no frantic meandering of thoughts, no clinging to details anymore. Once every few weeks I'm craving the euphoric buzz and drink half an Espresso, but typically regret it later the same day as I'm unable to sleep and, interestingly, tend to wake up in the middle of the night for a couple of days after.