With regular, (daily or every 2 days) relatively high dose abuse of both substances would IMO / IME could result in:
-Srong psychological addiction to both
-Serious bladder problems, long term wil destroy your bladder, have to have a "piss pouch and tube" or transplant maybe (Ket)
-Severe paranoia (coke)
-Risk of heart problems, possible heart attck(s), which can be fatal (cocaine)
-Isolating yourself socially (ketamine)
-Only having "drug friends" (both)
These are a few possibilities to consider...