Ambien, the top-selling insomnia drug in the United States, and Lunesta. (Bloomberg News)

White House physician Ronny L. Jackson allegedly provided travelers on White House trips with Ambien, a prescription sedative that is widely regarded as a safe drug that poses little risk of addiction. Nearly 30 million Americans take it for it insomnia — the vast majority of them in its generic form, zolpidem — for a single night or for longer periods of sleeplessness.

But that doesn't mean a physician can hand out the drug “like candy,” as Sen. Jon Tester (D-Mont.) said Jackson did, without inquiring about other medications a patient might be taking, drug history or other medical issues, experts said.

“Any physician prescribing a controlled substance should have a doctor-patient relationship, just because of knowing the other health problems and the other medications,” said Cathy Goldstein, an assistant professor of neurology at the University of Michigan School of Medicine and a physician at the Michigan Medicine Sleep Disorders Center. Taking Ambien, “you could get hurt. You could be disruptive, especially if you're using it with alcohol.”

Ambien and the stimulant Provigil, which Tester said Jackson dispensed to help travelers awaken, are Schedule IV controlled substances in the government's five-category ranking of drugs' risk of abuse. But like any medication, they pose some risk, particularly in certain groups.

During a news conference in January, Jackson said, “When we travel from one time zone to another time zone on the other side of the planet, I recommend that everyone on the plane take a sleep aid at certain times so that we can try our best to get on the schedule of our destination.”

Anecdotes abound of people behaving strangely under the influence of Ambien and being unable to remember that behavior when the drug wears off. Chris Winter, a neurologist at Charlottesville Neurology and Sleep Medicine in Virginia and author of “The Sleep Solution,” said a patient of his on the drug emerged from her bedroom naked and held a lengthy conversation with her in-laws. In 2006, then-Rep. Patrick Kennedy (D-R.I.) crashed his car into a barrier near the Capitol, citing disorientation from Ambien and another medication.

“It is not a harmless drug,” Winter said.

That is particularly true for older patients, who can become confused and unsteady or fall, said Thomas Scammell, a professor of neurology at Harvard Medical School and a sleep medicine specialist at Beth Israel Deaconess Medical Center.

“The truth is any sedating medicine has the tendency to make someone a bit addled at night,” Scammell said.

The drug allegations helped delay a Senate hearing on Jackson's nomination to head the Department of Veterans Affairs, the government's second-largest bureaucracy. Other alleged incidents have since emerged, including news that Jackson allegedly wrecked a government vehicle after getting drunk at a Secret Service going-away party.

While zolpidem carries little risk of physical dependence, people with chronic insomnia can become psychologically dependent on it, Scammell said, as they grow to believe that the medication is the only thing that will help them to sleep. Specialists prefer to use it as a short-term bridge to better sleep, he said, while they teach better sleep hygiene and techniques. That means avoiding cellphones, laptops and other screens near bedtime, cutting off caffeine intake by early afternoon, and using cognitive behavioral techniques such breathing exercises, which have proved as effective as drugs, the experts said.

If Jackson did pass out the drug indiscriminately on long government flights, he is not the only physician to do so. Staffers and news media traveling with the secretary of defense also have received the same offer.

More than 29 million people had prescriptions for the generic zolpidem in 2017, according to a spokeswoman for the drugmaker Sanofi, and 88,000 more had Ambien prescriptions. The numbers don't include controlled-release Ambien.

Experts said that when properly prescribed, Ambien has proven benefits beyond insomnia, including use when crossing many time zones. “It should not be taken in lieu of proper evaluation and treatment of other sleep issues,” said Jerald Simmons, founding director of Comprehensive Sleep Medicine Associates in The Woodlands, Tex. But “sleep loss itself has its downside,” including safety behind the wheel and the ability to perform other functions, he said.

“If you only get two hours of sleep,” Scammell said, “you’re not going to negotiate with the North Koreans as well.”

Similarly, Provigil — first developed to treat narcolepsy — and its successor Nuvigil, now have the approval of the Food and Drug Administration for treatment of “shift work disorder,” a circadian-rhythm condition caused by work schedules that do not jibe with natural sleep patterns.

But it shouldn't be prescribed in conjunction with Ambien, to help travelers stay awake, as Tester alleged, the experts said.

“For a sleep physician there is virtually no situation where we would be prescribing a hypnotic medication at night, like Ambien, and then a stimulating medication in the morning,” Goldstein said. “If somebody has residual sedation the next morning, the treatment is no more Ambien.”