Well, I am in Colombia (still) and cycling (barely - I took a month off and now I am suffering mightily). Several years ago I read an article on the Internet discussing the use of cocaine and performance enhancing drugs in professional cycling. Since Colombia is the world's leading supplier of cocaine, I thought I would do some research.
Before we get into the results of several scientific studies, here is a brief history of performance enhancing drugs in professional cycling:
It started with alcohol in the early 1900s. Cyclists commonly drank brandy in an effort to dull the pain. Suffice to say that many cyclists didn't know what they were doing back then (I drank of couple of beers during a 2010 end-of-season club ride, and I felt like crap). In 1924, a French newspaper, Le Petit Parisian, reported widespread use of cocaine in the Tour de France. The 1930 Tour de France rulebook stated explicitly that race organizers were not responsible for providing drugs to cyclists (implying that the teams, themselves, were responsible).
Cyclists started using amphetamines in the 1940s. Fausto Coppi apparently took seven packets of amphetamine when he beat the world hour record in 1942. Amphetamines, and a mixture commonly referred to as "Pot Belge" (a mix of heroin, cocaine, amphetamines, and caffeine) were the drug of choice until EPO rocketed through the peloton in the 1990s.
But the results could be tragic. A Danish cyclist, Knud Enemark Jensen, died in a 100km road race at the 1960 Olympics. The autopsy discovered amphetamines and other drugs. Tom Simpson, a British cyclist, died during a stage of the 1967 Tour de France. Amphetamines, alcohol, searing temperatures, and the intense physical effort of competition proved a fatal combination.
Aside from possible death, amphetamines are known to cause 1) a lack of judgement, and 2) a higher tolerance for risk-taking. Generally, this is not life-threatening, especially on an ascent. But plenty of director-sportifs and team-mates had cause for worry on the treacherous European descents. Apparently, there are pictures of Charly Gaul frothing at the mouth in the 1958 TDF (I couldn't find any in a quick online search). I have read other articles in the past describing how Eddy Merckx couldn't even see straight during several queen-stage descents.
Fans quickly realized that drugs ran rampant through the European peloton. RoadBikeRider.com reports that by the 1950s, following the TDF routes was simple - just look for the trail of discarded syringes and empty pill bottles. No need for arrowed routes.
Back to cocaine. According to ESPN, there is little-to-no athletic performance enhancement as a result of cocaine use. In fact, cocaine's reality-distorting properties create a false sense of performance. An athlete may think he/she is performing better, but just the opposite is true.
Furthermore, cocaine causes abnormal heart-rhythms, which can be life-threatening to athletes.
So, there you have it. Don't mix cocaine and cycling.
As for me, my favorite performance enhancer is a can of Coke-Cola 20 minutes before the end of a suffer-fest. The body is so depleted of carbohydrates by this stage, that the sugar reaches the muscles in several minutes. You have to be careful with timing, as the energy-levels peak and then rapidly fall again.
Viagra is also reported to be performance enhancing; inside and outside the bedroom. The Daily News reported in 2008 that Roger Clemens and several other athletes used Viagra on the field. They believed that the active ingredient, sildenafil, opened blood vessels and enriched the muscles. Viagra is available over the counter in Medellin supermarkets. I'll have to pop a pill or two before the group ride this Saturday.