I am a 28 year old male. I was prescribed Ritalin LA 30 mg around 6 months ago. I was always aware that I had difficulty focusing. After 30 minutes of taking the Ritalin in the morning I would receive a pretty great high. It lasts about an hour. I have had many experiences with cocaine in my youth and this is the exact same high. The morning buzz is no longer that strong but there is still a little energy push 30 minutes after taking the pill. Before I ask my question I must first state the following:
1) I don’t know how they can prescribe this to children. This is a powerful drug.
2) I don’t condone the irresponsible use of any prescribed drug or the use of any illegal narcotic.

Now for my question. On occasion, there is a presence of cocaine within my circle of friends. In the past, I would do a line or a bump and receive the typical cocaine high. Ever since being on the Ritalin, cocaine has Zero effect on me. I mean nothing. I have tried different batches and it is almost as if my brain is completely immune to it. I know this sounds as if I am some addict wanting to get a buzz. That is not the case at all. I am concerned that I somehow either burnt out any receptors that are triggered by cocaine or if the Ritalin acts as some sort of blocker. I just hope it is nothing serious. Please assist me in any knowledge that might shed some light on this concern of mine.

I thank you in advance.