West Bromwich defender Gabriel Tamas, who was with the Cesena striker at the time, shared the same fate, Piturca said late Wednesday after Romania beat San Marino 1-0.
"The two players have been expelled for life from the national team", Piturca stressed.
"It's a pity but rules are strict and they should have known it," he added.
Local media said that Mutu and Tamas, who had been involved in drinking bouts before, had gone out partying on Monday evening despite strict orders from the coach.
"We understand Piturca's decision," Mutu said.
The expulsions come less than a month before Romania resume their Euro-2012 qualifying campaign, against Luxemburg on September 2 and France four days later.
Nicknamed the "Brilliant" by Romanian fans, Mutu was suspended for taking cocaine in 2004 and still owes 17.2 million euros in damages to Chelsea, his club at the time.
In January 2010 he was banned for nine months by Italian club Fiorentina after he failed anti-doping tests.
When he returned in October, he was involved in a bar brawl and was almost forced to leave Fiorentina during the winter due to his poor attitude in training.
Last month he joined the modest Italian club of Cesena, saying he had come "to set an example and help the team progress".
After six qualifiers Romania are currently fourth in Group D, five points behind leaders France.