Ketamine/Calvin Klein every hour

I know a few people who are heavily addicted to ketamine and Calvin Klein (cocaine and ketamine). They do it every hour and a half in the bathroom at work (Amazon fulfillment). And much more on their days off I’m sure. My question is how much damage are they doing to themselves, and how long before they realize it? Have anyone in this group ever done it every hour? If so, what damage has it caused?