AUGUSTA — Assistant Senate Majority Leader Lisa Marrache, D-Waterville, is not running for re-election in Senate District 25, the Senate President confirmed Tuesday.

Marrache, a Waterville physician, has served 10 years in the Legislature.

Senate President Elizabeth Mitchell, D-Vassalboro, said Tuesday that Marrache dropped out because of difficulties juggling work and legislative service.

Marrache could not be reached for comment.

“What a loss,” said Mitchell, the Democratic candidate for governor. “Having her expertise as a doctor helped so much with legislation on health care. It’s a real loss to the Maine Senate.”

Senate District 25 covers Albion, Benton, Clinton, Unity Township, Waterville, Winslow, Detroit and Pittsfield. Democrats will need to name a replacement candidate for Marrache for the November election.

Republican Thomas H. Martin Jr., of Benton, has filed to run for the seat.

For Democrats, it’s the second high-profile defection from Senate races in the past few days. On Monday, the Kennebec County Democratic Committee announced it will meet June 30 to pick a replacement candidate for Senate District 21 after Rep. Nancy Smith, D-Monmouth, dropped out of that race.