It is left of the viewer's imagination to figure out if Harry Alexander lived or died. My guess is he probably lived. I think that doctor Mayfield was just trying to shoot him up with drugs to make him look like a active addict. After he said he was being cleaned up. Overall this was a great episode. I've watched it many times.
Just watched this episode again for the 100th time...it's amongst my favorites. I think Nimoy is one of the most diabolical criminals in the history of the show. He's smart, cold, calculating, and utterly ruthless. I also got a huge surprise when Columbo get mad...it's SO infrequent that it really comes across as special. As I watch this episode of Columbo in 2020 and during this infernal pandemic, it give me comfort, and much like Jeremy Brett in the Granada Sherlock Holmes, Columbo is ageless and as fresh today as it was when it first arrived on our tv's so long ago.