Kelley's effort is being roundly denounced, even though it won't appear in bookstores until next week.
Republican officials have dismissed the book as "garbage" and "fiction."
The New York Times reports that a "White House representative" has even asked NBC News President Neal Shapiro to cancel Kelley's appearances on the network's "Today" show. The author is slated to be on the morning program three days in a row next week.
The newspaper also said the GOP has sent a memo to conservative talk-show hosts listing unproved allegations that have appeared in previous Kelley books, including a biography of Nancy Reagan.
A central allegation in the gossipy new book is that years ago, President Bush used cocaine at Camp David while his father was the president. The source for Kelley's claim was reportedly Sharon Bush, the president's former sister-in-law.
Sharon Bush, who is estranged from the Bush family, quickly distanced herself from the allegation.
"I categorically deny that I ever told Kitty Kelley that George W. Bush used cocaine at Camp David or that I ever saw him use cocaine at Camp David," she said in a statement.
Doubleday, Kelley's publisher, stood behind Kelley's account, saying a Doubleday editor had been party to a conversation between Sharon Bush and the author.