Madeline Kahn left the show early in the run after having missed 10 performances in two months. She was replaced by her understudy, Judy Kaye. At the time, it was reported that the role was too vocally demanding for her to perform eight times a week, and that she had proposed having Judy Kaye play matinees. Judy Kaye took over full time on April 24, 1978. The notes in the booklet for the CD issue of the cast recording give that as the date of Madeline Kahn's last performance, but her last performance was on April 22.
Hal Prince stated in later interviews that she was having trouble commanding the energy to play physical comedy eight times a week, and his statements suggest that he and possibly the writers tried to persuade her to leave. At least a few critics, having attended critics' previews rather than opening night (when Prince says she was wonderful), did find her performance a bit lackluster, although most of her reviews were favorable.
The song list on this page reflects the song list in the playbill with two exceptions: the Overture wasn't listed, and what we've listed as "Entr'acte (Life Is Like a Train)" was listed in the playbill as "Entr'acte."
The complete cast list on the Full Credits page reflects the playbill "in order of appearance" cast list. There is one oddity in the cast list, which we've retained: Dr. Johnson actually made her first appearance — singing a reprise of "I Have Written a Play" that wasn't listed in the playbill — before the appearance of the Hospital Attendants. This out-of-order listing was never corrected during the run.
Mildred Natwick was originally announced for the role of Letitia Primrose. Charles Durning was also in an early cast announcement. He presumably would have played either Oliver Webb or Owen O'Malley had he ended up being in the production.