Fiona Gillies was the producers' first choice to play Clare Shearer, when the character was introduced in 1997. However, she was expecting a baby at the time, and so was unable to accept the role, which instead went to Yolanda Vazquez. When Vasquez decided to leave at the end of the 1997 season, the producers debated whether to kill off her character, but instead they approached Fiona Gillies. This time she was free to take over the role.
When the scriptwriters wrote the cliffhanger ending to season twelve, in which Alex and Claire fell (presumably to their deaths) over the side of a quarry, they expected that there would be another season. However, the producers subsequently decided not to make another season, feeling that Peak Practice had outlived its usefulness, and leaving the fate of these two characters forever unknown.
The house in Wessington, which was used as the location for David and Clare Shearer's house, was owned by Tim Parkin, the Medical Advisor to the program.
Kevin Whately, Sylvia Syms and Simon Shepherd all starred together in the BBC adaptation of Miss Marple: A Murder Is Announced (1985) in 1985.
Originally, Larry Lamb was due to join the regular cast in season four, playing Dr. Richard Carey, with Jane Wymark playing his wife. However, their characters were dropped after four episodes had been filmed. Some scenes in those episodes had to be edited or re-shot. New Producer Richard Handford left abruptly, and Michele Buck (Producer of earlier seasons) was asked to return.
Saskia Wickham's real-life parents, Jeffry Wickham and Clare Stewart, played the adoptive parents of her character, Erica Matthews.
In season five, Will and Kate's baby, Emily, is treated at a cystic fibrosis unit in Bristol, which is named after Vanessa Machin, a cystic fibrosis sufferer (played by Susannah Corbett) who appears in episode Peak Practice: Other Lives (1995).