“What hath night to do with sleep?” John Milton wrote in “Paradise Lost.”

For the millions of people who suffer from insomnia and need help from prescription drugs to sleep, Milton’s words are timeless.

Professional hockey players are no exception. Many have trouble sleeping and turn to prescription drugs such as Ambien. But like any other drug, Ambien can be abused and lead to harm. On May 13, 2011, New York Rangers forward Derek Boogaard was found dead at age 27 from an overdose of alcohol and drugs, including Ambien. According to The New York Times, Boogaard had as many as 25 prescriptions for the sleep aid from 10 doctors.

When it came to problems associated with sleep, the NHL has had its wake-up call. The league, in accord with the NHL Players’ Association, instituted rules this past offseason related to getting enough rest as part of its new collective bargaining agreement. Among them: Players must receive at least four days off per month during the season. Previously, days off were at the coach’s discretion. Also, from the time a team’s plane lands after a flight, no practice can be started before at least nine hours has elapsed.

The NHL and NHLPA formed a joint committee to study the use of Ambien by league players, and will make recommendations for monitoring and controls based on its findings by June 30.

“It’s certainly an important issue, which is why we put some things in the CBA,” NHLPA spokesman Jonathan Weatherdon said. “Things like the practices no earlier than nine hours later after landing, where hopefully you don’t have a situation where players have to rely on sleeping pills, because they have more time to sleep and they don’t have to rush to get to sleep because of an early-morning practice. Teams have tightened up on the use of Ambien and are making sure that guys are educated on making sure they are taking it as prescribed.”

In the U.S., studies have shown that as much as 10 percent of the public occasionally uses Ambien or other prescription sleep aids. Avalanche winger P.A. Parenteau said he uses Ambien.

“I’ve been taking it maybe every other night right now,” Parenteau said. “The other night, we got back from a road trip at 4 a.m. and I’m like, ‘OK, I need some.’ You try not to use it too often. I usually just take half a pill.”

Ambien can be dangerous when not taken as prescribed. It’s intended to be a temporary aid for sleep, with eight hours of rest necessary after ingestion. Performing actions that require alertness, such as driving, while under the effects of the drug can be dangerous. It can be habit-forming. Mixed with alcohol, it can be deadly.

Avalanche defenseman Ryan O’Byrne has been in the NHL since 2007. While he doesn’t believe Ambien use is a big problem leaguewide, Boogaard’s death is a cautionary tale, O’Byrne said.

“Used properly, it can be a helpful drug. But obviously, there’s been circumstances when it’s been overused,” O’Byrne said. “But sleep is an issue, especially in the Western Conference. We get in later than teams in the East, and when you have to play again the next night, or have a practice the same morning, it can be tough to get enough rest.”

Parenteau can vouch for that. Playing most of his career for Eastern teams, Parenteau was accustomed to getting back to his bed by midnight, even after road games. With the Avalanche, the travel time to and from road games is double, sometimes triple, what it is in the East.

“My sleep got kind of messed up from our travel. I’m still getting used to it,” he said.

The Avalanche wouldn’t comment on anything related to prescription drug procedures with players, which the new CBA mandates must be monitored by teams. Weatherdon said players can refuse any medication prescribed by a team if they’re not comfortable using it.

“I’m not sure it was ever a big problem back in the day, but maybe that’s because some of the drugs today didn’t exist back then,” former NHL coach Scotty Bowman said. “I think most hockey players, with all the physical activity they do, don’t have trouble sleeping. But I’m sure some players have problems and need to take something sometimes.”

Avs defenseman Jan Hejda said he uses sleeping pills, but only on rare occasions.

“Sometimes you’re just on the go so much, it’s hard to find time to rest,” he said. “You think you can get by without it sometimes. But you can’t. You have to get your sleep.”