From The Collaborative International Dictionary of English v.0.48:
Tope \Tope\, v. i. [imp. & p. p. Toped (t[=o]pt); p. pr. & vb.
n. Toping.] [F. t[^o]per to cover a stake in playing at
dice, to accept an offer, t[^o]pe agreed!; -- perhaps
imitative of the sound of striking hands on concluding a
bargain. From being used in English as a drinking term,
probably at first in accepting a toast.]
To drink hard or frequently; to drink strong or spiritous
liquors to excess.
[1913 Webster]
If you tope in form, and treat. --Dryden.
[1913 Webster]