In a 2011 interview with "The A. V. Club," David Hyde Pierce said that it cost him more to join the Screen Actors Guild (so that he could appear in this movie) than he was paid for his role, so he had to borrow the dues money from his agent. His character's name was "Bartender at Fashion Show", and his one line was, "Sorry, the bar is closed."
The substance used to depict cocaine was really a powdered milk substance known as "milk sugar".
The book "Bright Lights, Big City" is one of the few well-known novels in the English language written in second person ("you") form, and the film's narration is a result of this adaptation. Much of the narration is lifted directly or adapted from the novel; for example, the movie's first line, "You are not the kind of guy who would be at a place like this at this time of the morning . . . " is also the first line of the book.
In seven days James Bridges wrote a new draft and got rid of six cast members, replacing them with Jason Robards, Jr. John Houseman, Swoosie Kurtz, Frances Sternhagen and Tracy Pollan while keeping Kiefer Sutherland and Dianne Wiest. Those cast members took the part based on a reading of the novel, since there was no script at the time.
Dianne Wiest: As the mother of Michael J. Fox. Her character is never known by any personal name, and is billed in the credits only as "Mother".