German Skier, Italian Bobsledder Fail Doping Tests

The Sochi Games have become the most tested in Winter Olympic history.

Feb. 21, 2014— -- intro: A German skier and Italian bobsledder have been kicked out of the Sochi Games after testing positive for banned substances, according to their countries' Olympic Committees.

Germany's Evi Sachenbacher-Stehle, a 33-year-old biathlete, was disqualified after testing positive for the stimulant methylhexanamine, the Associated Press reported.

Sachenbacher-Stehle, who won two golds and three silvers in cross-country skiing in previous games, claims she never knowingly took performance-enhancing drugs and blamed the positive test on a nutritional supplement.

"I am going through the worst nightmare that you can imagine, because I am unable to explain at all how there could be a positive test," she said in a statement, adding that she had her supplements checked out by a lab before the Olympics.

The World Anti-Agency classifies methylhexanamine as a "specified stimulant" that is more susceptible to inadvertent use.

Italy's bobsledding brakeman William Frullani tested positive for a different stimulant known as dimetylpentylamine, losing his place in Saturday's four-man run.

Sochi Winter Olympics 2014 Live Blog

The Sochi Games are the most tested in Winter Olympic history with officials collecting an estimated 2,453 blood and urine samples, according to the IOC. That's up from 2,149 in Vancouver, 1,200 in Turin and 700 in Salt Lake City.

Only one athlete tested positive for a banned substance in Vancouver, while Turin and Salt Lake City recorded seven positive tests each.

The World Anti-Doping Agency has a long list of banned substances ranging from stimulants to steroids. Click through to find out how they work and the side effects they carry.

quicklist: 1category: Performance-Enhancing Drugs Cheat Sheettitle: Anabolic Steroidsurl: text: How They Work

Anabolic steroids are synthetic versions of the male hormone testosterone. The drugs promote muscle growth, not to mention signs of male puberty, from body hair to voice changes.

The Health Risks

Steroids disrupt the normal production of hormones, prompting shrinking of the testes and breast development in men. More serious side effects include heart attacks and cancer.

How Often They're Used

Anabolic steroids are the most commonly reported banned substance, accounting for 50.6 percent of incidents reported to the World Anti-Doping Agency in 2012.

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quicklist: 2category: Performance-Enhancing Drugs Cheat Sheettitle: Hormones and Growth Factorsurl: text: How They Work

Testosterone isn't the only naturally-occurring substance exploited for its performance-enhancing effects.

The hormone erythropoietin, dubbed EPO, boosts the production of red blood cells, which deliver oxygen to muscles. And insulin-like growth factor (IGF) and human growth hormone (HGH) are thought to increase muscle strength and speed the recovery from injury.

The Health Risks

EPO's blood-thickening effects raise the risk of heart disease and stroke. And growth factors can raise the risk of diabetes, cardiovascular diseases and pain in the muscles and joints.

How Often They're Used

Peptide hormones and growth factors accounted for 4 percent of all WADA incident reports in 2012.

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quicklist: 3category: Performance-Enhancing Drugs Cheat Sheettitle: Beta-2 Agonistsurl: text: How They Work

Asthma drugs such as Clenbuterol that open up the airways are sometimes used by nonasthmatic athletes to boost lung function. But the jury's out on whether the drugs, dubbed beta-2 agonists, actually enhance performance, with some studies suggesting a slight advantage while others failed to find a benefit.

The Health Risks

Side effects of the drugs range from headache and insomnia to tremors and muscle cramps. They're also considered habit-forming and can cause increases in heart rate and blood pressure.

How Often They're Used

Beta-2 agonists accounted for 2.9 percent of all WADA incident reports in 2012.

quicklist: 4category: Performance-Enhancing Drugs Cheat Sheettitle: Metabolic Modulatorsurl: text: How They Work

Drugs that alter the amounts of circulating hormones like estrogen aren't themselves performance-enhancing. Rather, they're used to fight the unwanted side effects of steroids, such as male breasts and testicular atrophy.

The Health Risks

One of the so-called metabolic modulators, the breast cancer drug tamoxifen, has been linked to blood clots and certain cancers.

How Often They're Used

Metabolic modulators accounted for 1.6 percent of all WADA incident reports in 2012.

quicklist: 5category: Performance-Enhancing Drugs Cheat Sheettitle: Diureticsurl: text: How They Work

Drugs designed to make you pee are sometime used by athletes to mask the use of performance-enhancing drugs that can be easily detected in urine.

The Health Risks

Diuretics can trigger electrolyte imbalances and lead to dehydration, which can cause low blood pressure and blood clots.

How Often They're Used

Diuretics accounted for 7.2 percent of all WADA incident reports in 2012.

quicklist: 6category: Performance-Enhancing Drugs Cheat Sheettitle: Blood Manipulationurl: text: How It Works

Just as EPO can be used to boost the number of oxygen-carrying red blood cells, blood transfusions can directly inject an extra dose of oxygen-rich red blood cells into the blood stream.

Synthetic versions of the iron-based molecule that tethers oxygen to the blood cells, hemoglobin, are also used as a performance-enhancing drug.

The Health Risks

Blood transfusions carry the risk of infection, and abnormally high red blood cell counts can lead to heart disease and stroke.

Synthetic oxygen carriers can also raise the risk of cardiovascular disease.

How Often It's Used

Blood manipulation accounted for 0.2 percent of all WADA incident reports in 2012 – a single case.

quicklist: 7category: Performance-Enhancing Drugs Cheat Sheettitle: Stimulantsurl: text: How They Work

Substances such as caffeine and the ADHD drug methylphenidate can increase energy and alertness, as well as blood flow to muscles. They also decrease fatigue.

The Health Risks

Stimulant drugs can cause abnormal heart rhythms and palpitations, tremors and insomnia. Certain drugs, like cocaine, are also addictive and can be deadly in high doses.

How Often They're Used

Stimulants are the second most reported banned substance behind steroids, accounting for 15.5 percent of all WADA incident reports in 2012.

quicklist: 8category: Performance-Enhancing Drugs Cheat Sheettitle: Narcoticsurl: text: How They Work

Narcotic drugs that block pain like morphine and oxycodone can help athletes compete through injuries.

The Health Risks

The powerful painkillers can slow the heart rate as well as breathing. They can also lead to addiction.

How Often They're Used

Narcotics accounted for 0.6 percent of all WADA incident reports in 2012.

quicklist: 9category: Performance-Enhancing Drugs Cheat Sheettitle: Cannabinoidsurl: text: How They Work

Marijuana can actually inhibit athletic performance by reducing cardiac output and reaction time. But it also works to reduce anxiety, which might be why cannabinoids are the third most commonly reported class of drugs in competitive sport.

The Health Risks

Cannabinoids can cause restlessness and panic attacks in high doses.

How Often They're Used

Narcotics accounted for 9 percent of all WADA incident reports in 2012.

quicklist: 10category: Performance-Enhancing Drugs Cheat Sheettitle: Glucocorticosteroidsurl: text: How They Work

Glucocorticosteroid injections can help suppress inflammation, helping athletes get back on their feet after joint and tendon injuries.

The Health Risks

The drugs can cause pain and infection at the injection site.

How Often They're Used

Narcotics accounted for 8 percent of all WADA incident reports in 2012.

quicklist: 11category: Performance-Enhancing Drugs Cheat Sheettitle: Beta-Blockersurl: text: How They Work

Blood pressure-reducing beta-blockers are banned from sports like darts and golf because of their anti-anxiety effects.

The Health Risks

The drugs can cause headaches and dizziness but are generally considered quite safe.

How Often They're Used

Beta-Blockers accounted for 0.3 percent of all WADA incident reports in 2012.