Ricki starred in a number of episodes in Season 3 as Doug's sister, Stephanie, a frumpy character, but then disappeared.

I wonder if Ricki didn't like the character and thus didn't want to play it anymore, since it was a major downgrade from being a star of a talk show for 10 years.

Or did the show not want her? From a story perspective, she seemed to fit in well as Doug's sister and as a second child to Doug's parents - who guested on the show on many seasons. Generally, different than Carrie's sister who was written off the show.

Anyone know?

On a side note:
There was also one episode with Stephanie hooking up with Carrie's boss, Pruzan, and then a few seasons later, Holly and Carrie's boss, Pruzan, similar story. (Kind of a repeat story)

Ricki Lake: Queen of Queens

Ricki Lake is only halfway through her six-episode stint as Kevin James's sister on The King of Queens, and already producers of CBS's hit sitcom are begging her to quit her day job. "They want me there every week," Lake tells TV Guide Online. "They're like, 'Wait a minute, can't your talk show go away? Can't it be cancelled?'" Not likely. Although Lake says she's "so psyched" to be a part of Queens, the native New Yorker insists she has no plans to put down her microphone anytime soon. "My talk show is not going anywhere," she says. "I truly love going to work every day. I love talking to people about the inner-most details of their life.

https://www.tvguide.com/news/ricki-lake-queen-37214/

Thanks. I assumed her 90s talk show had already ended but it actually overlapped. Surprised they couldn't get to reprise her role even for 1 or 2 more episodes in the later seasons.

She was good for sure. I guess she had moved on by then.