Green’s Dictionary of Slang

(drugs) Pantopon, a synthetic opiate.

1962		B. Jackson Get Your Ass in the Water (1974) 114–5: ‘You’re young and fine and you want to score, / from now on, jack, I’m gonna be your whore.’ / Now she named him Ping Pong Joe and put him on his feet, / and he was the sharpest junkie, Jack, to ever hit the streets.
1963		R.I. McDavid Mencken’s Amer. Lang. 726: Prisoners in the Virginia State Prison (1942) had a long list of local names for various mild narcotics [...] cement, codeine; ping-pong, pantopon.