EXPOSED! JFK ran naked in posh hotel after a methamphetamine injection from notorious Dr. Feelgood put the “entire civilized world at risk” as John F. Kennedy’s drug dealer has been exposed in a blockbuster book.

Dr. Max Jacobson – known as Dr. Feelgood – repeatedly injected JFK with dangerous methamphetamine to keep him pain-free from war injuries and alert during his political battles.

But in one terrifying incident, the Commander-in-Chief suffered an overdose resulting in a horrific break from reality, reveal authors Richard Lertzman and William J. Birnes in their book, “Dr. Feelgood”.

Jacobson, who had a Who’s Who list of celebrity clients, had been treating the young President for some time when in the spring of 1962 he was called to New York City’s Carlyle Hotel – and things went terribly wrong.According to the authors, the shady doc overdosed the Leader of the Free World.

“After Jacobson left the Carlyle, the President, who at first felt invigorated and vibrant, suddenly began suffering from a serious psychotic reaction to the drugs and became manic,” they write. “It was an absolute psychotic break. He peeled off all of his clothing and began prancing around his hotel suite.” The Secret Service became alarmed when he left the suite and began roaming the corridor.

“He was completely naked, on the verge of paranoia, and feeling so free of pain.”

Dr. Lawrence Hatterer, a Big Apple psychiatrist, was called. He later stated he saw the President “in a manic condition furiously waving his arms and running around without any clothes on.” Hatterer recognized “drug-induced mania,” the authors write.

He then injected Kennedy with an antipsychotic and another drug that calmed him down.

JFK first fell into Dr. Feelgood’s clutches in 1960 after an introduction from his Harvard roommate, Chuck Spalding.

In the middle of his fierce presidential campaign the U.S. Senator from Massachusetts  felt drained, fatigued, weak and was coming down with laryngitis. He was soon to face his Republican rival Richard Nixon in America’s first televised debate.

JFK told Feelgood he drank a lot, took phenobarbital for his irritable bowel syndrome, cortisone steroids for his Addison’s disease, painkillers for his back, sleeping aids, antibiotics for various infections – and was being treated by Dr. Janet Travell for back pain with procaine injections.

Jacobson promised his “vitamin cocktail” would help with everything and relieving stress was one of his specialties.

The authors say the drug-dealing doc knew the powerful stimulant might be dangerous to JFK – but “it was a risk Jacobson was willing to take.”

JFK didn’t give a second thought to what was in the syringe and experienced what Truman Capote had described as “instant euphoria. You feel like Superman,” the authors write. That was just the ticket JFK needed! Jacobson gave him a vial of “vitamin” drops – another dose of methamphetamine – that he could take orally before his face-off with Nixon.

BUT that wouldn’t be enough for Kennedy, who visited the doc on the evening of the debate in September 1960.

“This time, Jacobson inserted his needle directly into Kennedy’s throat and pumped methamphetamine into his voice box,” the book says.

After Kennedy won the presidency, Jacobson was invited to inaugural events, where he met an upcoming patient, Jackie Kennedy. JFK even asked Jacobson to join him for the Vienna Summit with Nikita Khrushchev in 1961.

Shortly before the trip, the doctor’s shabby medical offices were ransacked by the KGB looking to confirm reports Kennedy was taking drugs. Vienna turned out to be a disastrous trip. Khrushchev was late and by the time he arrived, Kennedy had taken three injections of methamphetamine that caused “an almost stupor-like depression.”

Kennedy would later describe the meeting as the worst day of his life.

Still, he asked Jacobson to move into the White House so he’d always be close by. But Feelgood declined, not wanting to give up his New York practice and his other A-list  clients.

Before he died in 1979, Jacobson had hooked the likes of Marlene Dietrich, Liz Taylor, Judy Garland, Ingrid Bergman, Hedy Lamarr, Arlene Francis and Rosemary Clooney, the authors write.

Marilyn Monroe, another of Jacobson’s victims, came down with stage fright on the big night in May 1962 she was to sing Happy Birthday to the President at Madison Square Garden – so Jacobson shot her up.

But perhaps the most frightening thing of all, the authors write, “In the eyes of the CIA, Jacobson’s injections had put the office of the presidency, the nation, and perhaps the entire civilized world, at risk.”