Outer space, at least as we encounter it in science fiction, is basically a drug free-for-all. If character's aren't piloting starships on Melange or Somec, then they're playing with dolls on Can-D or pumping their brains full of Merge Nine, Semuta and whatever passes for rave music 20,000 years from now.
But let's steer clear of the fictional space drugs and consider the buffet of pharmaceuticals that real astronauts might indulge themselves in.
Booze: While coffee continues to be readily available in space, alcohol is more of a gray area. In 1969, Buzz Aldrin consumed communion wine on the moon and, if you believe some of the stories, the Russian MIR space station was practically swimming in vodka. While the ISS is technically a dry operation, NASA came under scrutiny in 2007 amid reports of astronauts hitting the bottle before takeoff. It's hard to argue drinking in orbit is a good idea, but that hasn't stopped scientists from developing space brews. According to New Scientist, a University of Colorado student, with a little help from Coors, actually sent a miniature brewing kit into orbit as part of her thesis on fermentation in space. The results were reportedly rather foul, but it's just as well. Without gravity, you can't get a good head on a pint anyway.
Modafinil: You may know it as Provigil, Alertec, Vigicer or Modalert, but astronauts know it as the upper they take when sleep isn't an option. The Good Drug Guide describes it as "a memory-improving and mood-brightening psychostimulant" that "enhances wakefulness, attention capacity and vigilance." You have to love vigilance-enhancing chemicals. According to a 2009 report in the Canadian Medical Association Journal, Modafinil helps ISS crew members optimize their performances, no matter how fatigued they feel.
Scopolamine: In order to avoid blasting forth some low-gravity vomit, astronauts sometimes turn to ScopeDex, a speedy cocktail of Scopolamine and Dexedrine to combat nausea. According to Xeni Jardin at BoingBoing, good old Scopolamine is also known as "devil's breath" in Colombia, where criminals use it to turn unsuspecting victims into temporary zombie slaves. The CIA even experimented with the stuff as a truth serum in the '60s. Perhaps the lesson here is to use zombie mind-control drugs responsibly while in orbit.
Zoledronate: Bone-mass loss is one of the more detrimental side effects of space travel, so it's only natural that we'd try to dream up a drug to combat it. Enter zoledronate, normally used to prevent secondary bone tumors in cancer patients. According to BioEd Online, the drug showed promise a few years back as a means to slow the effects of low-gravity bone-mass loss. NASA continues to research its potential.
Anti-moon dust pills: Lunar dust is a huge nuisance. It can damage sensitive equipment and, if it coats your space suit during an Earthlit stroll, it can absorb enough solar energy to bake you in your suit. The National Space Biomedical Research Institute (NSBRI) has also pointed out that, if tracked into a low-gravity lunar base, it could wind up inside human lungs. According to Science Daily, there are no known illnesses due to lunar dust exposure, but it has a lot in common with fresh-fractured quartz, a highly toxic substance. The long-term effects could be quite harmful, leading NSBRI researchers to propose the use of target drugs to minimize the effect of tiny particles suspended in the lung.
Tranquilizers: Yes, according to a 2007 report from the Associated Press, astronauts keep a few tranqs on hand in case anyone goes all suicidal or psychotic in space. NASA recommends binding the individual's wrists and ankles with duct tape (ever the space traveler's friend!), strapping them down with a bungee cord and, if necessary, sticking them with a tranquilizer. Sure, it hardly makes for a civilized evening aboard ISS, but it beats someone blowing the hatch because they think they saw a something crawling on one of the solar panels.
Finally, it's important to keep in mind that drugs have a shorter shelf life in space. According to Space.com, NASA has observed that the effectiveness of some drugs decreases after travel aboard the space shuttle or the ISS. So there's another obstacle to manned deep-space exploration.
You can return to your purely imaginary space substances now. Speaking of which, just what fictional space drugs do you find most amusing in film, TV or literature? Can you name the books and films I referenced in the first two paragraphs?