But when pressed, Ms. Sanders said she could not comment on the credibility of specific charges.

“These are new,” she said. “I can only speak to some of the personal accounts that those of us have, as well as the records that we have that are substantiated through a very detailed and thorough background investigation process.”

Among those new charges she did not address: During an overseas trip by the Obama administration in 2015, Dr. Jackson went out drinking, came back to the delegation’s hotel and began banging on the door of a staff member’s hotel room, according to an account shared with Mr. Tester. The noise was so loud that members of the Secret Service came to see what was happening and warned Dr. Jackson to be quiet so he would not wake the president, who was staying nearby.

The episode was first reported by CNN.

On another trip during Barack Obama’s presidency, White House staff members reached out to Dr. Jackson for medical reasons but found him passed out in his hotel room after a night of drinking, Tester aides said. The staff members took the medical supplies they were looking for without waking Dr. Jackson.

The document prepared by the Democratic staff of the Veterans’ Affairs Committee paints a picture of a medical office that was casual with the prescribing and distribution of drugs but terrorized by a mercurial boss, quick to anger. According to the summary, interviewed staff members described Dr. Jackson as “the most unethical person I have ever worked with,” “flat-out unethical” and “incapable of not losing his temper,” among other charges.

The document includes allegations that Dr. Jackson regularly distributed Ambien, a prescription sleep aid, to members of the White House staff and members of the news media flying on long overseas trips, as well as another prescription drug to promote wakefulness.

It says that the committee was told that physicians working with Dr. Jackson “felt uncomfortable and refused to be a part of the loose dispensing of drugs to current and former” White House staff members. It also states that Dr. Jackson “also had private stocks of controlled substances.”