(CNN) — It was a fun flight for travel writer John Vlahides as he flew from London to San Francisco in 2008. He taught a flight attendant how to tie a Bedouin turban with an airplane blanket, and then showed a sleepless young boy how to make paper airplanes. Sailing them over passengers' heads in the economy cabin caused quite a ruckus.
It might have been a great way to pass the time on a boring overnight journey, except for one thing: John thought he was sleeping. After downing two small bottles of wine he had taken one milligram of a tranquilizer and 10 milligrams of Ambien, a popular sleeping aid.
Settling down for a long snooze, he had no idea he had been sleepwalking until he saw the photos and selfies on his smartphone the next day.
"The weird thing was remembering it all when I saw the pictures," Vlahides said. "And you say, 'Oh my God' and you cringe."
John Vlahides with a turban and paper airplane he unconsciously made while under the influence of sleeping pills.
Vlahides had become what many flight attendants unflatteringly call an "Ambien zombie." But Vlahides was lucky. He hadn't done anything too embarrassing, unlike other unlucky sleepwalkers.
A flight attendant who called herself "Betty" wrote about "The Streak" in a Yahoo article called "Confessions of a Fed-Up Flight Attendant: Attack of the Ambien Zombies."
The streaker was a sleepwalking economy passenger who had taken off all his clothes and decided to run up the aisle to first class. According to the story, he was stopped by flight attendants and told to don his clothes; he only realized his humiliating exploit when he later woke with his underwear in his hand.
Flight attendants told similar stories to Mayo Clinic sleep specialist Dr. Lois Krahn during her research on inflight substance use and jet lag. Krahn tells her patients one disconcerting tale as a warning about the potential dangers of sleeping aids, especially if combined with alcohol.
"This trans-Pacific and business class passenger mixed alcohol and Ambien and then woke needing to relieve himself," Krahn said. "He stood up and urinated on the passenger sitting next to him.
"Can you imagine how hard it was to calm down the business class cabin for the rest of the night?," Krahn added with a chuckle.
Do people on sleeping aids really behave this way on a plane and not remember?
"It's true, I've seen the pictures," said Taylor Garland, spokesperson for the Association of Flight Attendants. "But I would say those are some pretty extreme circumstances. It's not necessarily an everyday occurrence."
More common on planes, said Garland, is for the dosed sleeper to reach out and fondle their unlucky seatmate.
Ambien, or zolpidem tartrate, belongs to a class of drugs called sedative-hypnotics. Prescribed to treat insomnia for adults over the age of 18, it works by slowing brain activity.
"One of the normal side effects of Ambien is that it basically turns your brain into Teflon. You don't lay down any new memories," said Dr. Julie Holland, a psychopharmacologist who practices in Manhattan.
"And the other thing that happens is that you get sort of disinhibited, the way that you would if you were drunk or had taken Xanax or Ativan or Valium or something like that," Holland said. "So you get very relaxed and disinhibited, and you don't remember what you're doing."
If you're in bed and asleep that's not an issue. To ensure that, the manufacturer of Ambien has clear-cut safety information on its website: Don't take Ambien more than once per night and take it just before going to bed. Don't take Ambien unless you can stay in bed for seven to eight hours.
It's tough to follow those instructions on a plane, Holland warns.
"You're not really sleeping deeply because the lights are on, there's people around and tons of interruptions by flight staff," Holland said. "Or you may take the sleeping pill and not fall asleep, and then you are going to be in this altered state."
That's what happened to Vlahides on his transatlantic journey a decade ago. A friendly flight attendant interrupted just as he'd taken his sleeping pills to ask about his career as a travel writer.
"If she hadn't been bored on an empty flight and kept me awake, I'm absolutely certain it wouldn't have happened," said Vlahides, who later wrote about the funny incident. "But she was wonderful and she was fun. Who can say 'no' to that?"
Embarrassing, even dangerous behaviors
Activities that can happen in an altered state include "sleep-walking or doing other activities when you are asleep like eating, talking, having sex, or driving a car," according to the Ambien safety warnings, as well as "not thinking clearly" and "acting strangely, confused, or upset."
Those behaviors make sense to Holland. "When people are disinhibited, anything can happen because you're talking about basic primal instincts that are coming out. What are our basic instincts? To have sex and eat and sometimes to be aggressive."
Travelers often make the possible side effects worse by combining them with tranquilizers and alcohol, said Dr. Rajkumar Dasgupta, an assistant professor at the Keck School of Medicine at the University of Southern California.
"The worst thing you can do is drink alcohol on a plane," Dasgupta said. "You're already dehydrated, you have a lot of travel fatigue, and on top of that you're adding sleeping aids to it."
Another factor: a preexisting sleep disorder. For example, it's estimated that one billion adults in the world suffer from obstructive sleep apnea, a condition in which the throat muscles relax and your breathing stops and starts.
"When you're in a plane, the air is thin up there," Dasgupta said. "Even though they pressurize the cabin to 8,000 feet, it's still going be thinner air, less oxygen. You don't want to be on a sleep medication that will depress your respiratory drive."
Sleeping pills can also affect women and the elderly differently, said Krahn.
Alcohol can also cause blackouts. Drinking is linked to many complaints of passenger bad behavior.
"Ambien lasts about four to five hours for most people, a little longer for women, a little longer for older people," she said. "They may not remember to collect their bags when the plane lands or leave things behind like a wallet or passport because they are not as sharp under the lingering effects of the sleeping pill."
Ambien isn't the only sleeping aid that can cause parasomnias, or unwanted behaviors that happen when transitioning between different stages of sleep. At times, those behaviors have had tragic outcomes.
Following reports of "rare but serious injuries and deaths resulting from various complex sleep behaviors," the Food and Drug Administration decided earlier this year to require black box warnings on zolpidem (brand names Ambien, Ambien CR, Edluar, Intermezzo, and Zolpimist), eszopiclone (Lunesta), and zaleplon (Sonata).
Anyone who has experienced an episode of an odd sleep behavior while on one of these sleeping aids should discontinue their use after consulting with their doctor, the FDA said.
Sanofi, the company that manufactures Ambien responded to the issue of erratic behavior on planes by saying, "We encourage any patient prescribed a Sanofi medicine to work with their healthcare provider to ensure the treatment is taken properly."
Tips for sleeping on a plane
What can a weary traveler do to avoid a sleepless overnight flight? Sleep specialists CNN spoke with offered five key tips:
1. Avoid pharmaceutically induced sleep
"It's not something to be messing around with," said clinical psychologist and sleep specialist Michael Breus. "Certainly you should never be taking a medication like that for the first time while in the air, because you don't know how you're going to react to it, or if it might interact with any of your existing medications."
2. Try melatonin instead
"That's my preferred option for an overnight flight," said Mayo's Krahn. "You want to take it when you've got enough time for it to take effect."
Breus, who also recommends melatonin, said the time depends on the type of melatonin you choose.
"When you take it in a pill form, it has to go down to your stomach and then get up to your brain. That takes about 90 minutes," Breus said. "If you were to take a tincture or a sublingual under the tongue, then you're looking at 20 to 25 minutes, which is much more like an Ambien type of sleeping aid."
Krahn recommends three milligrams of melatonin, and suggests sticking with the short acting version to avoid feeling groggy if awakened too soon.
"There are some people who will say, 'I just can't handle melatonin because I feel too foggy and I have some concentration difficulties,'" Krahn said. "If they awakened too early when the melatonin is still in their blood and in their brain, that's probably a very real experience.
"So for someone who's flying early evening or during the day, it may not match up with their circadian pattern," Krahn said.
3. Limit alcohol
Alcohol interferes with sleep, said Breus, who has written several books on better sleep and writes a regular blog on the topic. It's dehydrating and interferes with sleep rhythms, he said, thus keeping you in the lighter stages of slumber when onboard airplane noise and distractions can jostle you awake.
4. Pack a sleep kit
Breus said he doesn't "wing it" when it comes to plane travel. He keeps a well-stocked sleep kit at the ready.
An eye mask is critical, he said, to block out unwelcome rays. Ear plugs, a well-designed travel pillow, a light blanket or sweater (for those airlines that no longer provide blankets), an audiobook and relaxing playlist makes his list, along with noise-cancelling headphones and water to stay hydrated.
5. Plan ahead
As much as possible, try to plan your sleep around the timing and purpose of your flight, Dasgupta said.
"Do you need to be alert right away?" Dasgupta asked. "If yes, then perhaps the lesser of two evils will be drinking caffeine in the morning before your meeting instead of taking a sleeping aid on the plane. Get out into the sunlight, get some morning exercise. Those are always winners."
Try these tips, say experts, and you could avoid the fate of becoming another airplane Ambien zombie. Unless you enjoy embarrassing yourself, of course.