A federal judge in Washington yesterday removed himself from presiding over a drug case in which a police informant had alleged that he had seen the judge at the home of a doctor connected to the case.

During a closed hearing last week, U.S. District Judge Barrington D. Parker took the witness stand and testified that he did not know the informant, Nathaniel Lee Edwards, and had never been to the home of Dr. Marshall D. Nickerson.

Nickerson, who is alleged to have written prescriptions for a third person charged in the case with conspiracy and drug distribution, appeared before Parker in December 1979. He pleaded guilty to one count of mail fraud and a drug distribution charge and was later sentenced to serve six months in jail.

Edwards had told police investigators that he saw a "judge" whom he later identified as Parker at Nickerson's Southwest Washington home in mid-1979.

Yesterday, U.S. Attorney Charles F. C. Ruff formally asked Parker to step down from the case.

In court papers asking that Parker disqualify himself from the Bramson case, Ruff said that the issue was not whether Edwards' allegations were true, but whether Parker could impartially preside over a trial in which Edwards would be the key government witness.

Ruff said in court papers that Edwards' credibility as a witness is a major point in the case and he noted that Parker in his own testimony last week stated that Edwards' statements about him were false.

Ruff also noted that it was a possibility that Parker himself could become a subject of testimony at the Bramson trial or even a witness in connection with defense efforts to discredit Edwards.

Parker said yesterday that in the interest of "fairness and justice" he felt he had to step down from the case and have it assigned to another judge. Parker said that the police informant either "suffers from some severe visual and other acute disabilities or he has absolutely no regard for the truth."