WASHINGTON - A new biography asserts that Richard Nixon over many years took a mood-altering drug without a prescription and that he beat his wife at times of personal crisis - a claim a Nixon intimate calls ''inconceivable.''
''The Arrogance of Power'' by Anthony Summers will be published Monday. It chiefly concerns the aspects of Nixon's life ''that he and his supporters have preferred to conceal,'' writes Summers, a BBC journalist and author of biographies of J. Edgar Hoover and Marilyn Monroe.
The author named his sources for most of the book's assertions. But many of those he quotes got their information second-hand. Some of the book's claims have been made in the past but in less detail.
The book said that in 1968 Nixon was given 1,000 capsules of the drug Dilantin, an anti-convulsant used to counter epileptic seizures, by Jack Dreyfus, founder of an investment firm and an enthusiastic promoter of the drug. Dreyfus later supplied another 1,000, it said.
White House physician Dr. Walter Tkach, ''a compliant doctor who would do exactly as a patient asked,'' was also a user of the drug himself, the book said, citing Nixon aide John D. Ehrlichman as its source.
When asked later if Nixon was still taking the drug, Tkach replied, ''I don't know, but the amount of pills in the bottle in his bathroom is reducing in size, so I suppose he is,'' according to Summers.
''The Physicians' Desk Reference'' lists a number of adverse reactions to Dilantin, including slurred speech, decreased coordination and mental confusion.
Summers wrote that the relationship of Nixon and his wife was one of ''prolonged marital difficulty, of physical abuse, of threatened divorce.'' But that view was contested by John Taylor, Nixon's chief aide in his retirement years, now director of the Richard M. Nixon Library and Birthplace in Yorba Linda, Calif.
Summers' claims that Nixon abused his wife came from secondary sources. Among others, he cited journalist Seymour Hersh, who said he learned of three instances of Nixon wife beatings but did not identify his sources; retired Washington lawyer John Sears, who was a campaign consultant to Nixon; and the late Bill Van Petten, a Los Angeles area reporter, who years later told a friend, not identified by Summers, that just before or after his 1962 loss to Brown Nixon beat Mrs. Nixon ''so badly she could not go out the next day.''
Summers said Sears told him that he had been told ''that Nixon had hit her (Pat Nixon) in 1962 and that she had threatened to leave him over it. ... I'm not talking about a smack. He blackened her eye.'' Sears said he had been told of the beating by two lawyers, both now dead, Walter Taylor and Pat Hillings.
Twenty-two years later, after he resigned in disgrace over the Watergate scandal, Nixon ''attacked'' his wife at their home in San Clemente, Calif., and she had to be treated at a hospital, Summers wrote, citing Hersh as his secondary source.
The New York Times, which carried a story about the book Sunday, quoted Taylor, the former Nixon retirement aide, as responding on behalf of Nixon's daughter, Julie Nixon Eisenhower.
''It cannot possibly be true,'' Taylor told the Times. ''It is utterly inconceivable. Anyone who knows and worked with President Nixon knows first of all that he could not have done it, second of all that he would not have done it and third of all that had he done it there are innumerable people who would not have spoken to him and yet remained active in his life and in Mrs. Nixon's life until their deaths and beyond.''