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Krokodil, a flesh-eating drug which first surfaced in Russia more than a decade ago, has reportedly been found in the United States.

Similar to morphine or heroin, krokodil is made by mixing codeine with substances like gasoline, paint thinner, oil or alcohol. That mixture is then injected into a vein, potentially causing an addict's skin to turn greenish, scaly and eventually rot away.

Dr. Frank LoVecchio, co-medical director at Banner Good Samaritan Poison and Drug Information Center in Arizona, told CBS5 that the first two cases of people using the drug have been reported in the state. He declined to comment on the patients' conditions.

"As far as I know, these are the first cases in the United States that are reported," LoVecchio said, adding that the cases are believed to be linked. "So we're extremely frightened."

Users of krokodil — or desomorphine — had previously only been found in large numbers in Russia, where 65 million doses of the opiate were seized during the first three months of 2011, Russia's Federal Drug Control Service told Time.

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"This is really frightening," Dr. Aaron Skolnik, a toxicologist at Banner Good Samaritan Poison and Drug Information Center told MyFoxPhoenix.com. "This is something we hoped would never make it to the U.S. because it's so detrimental to the people who use it."

To produce the potentially deadly drug, which has a comparable effect to heroin but is much cheaper to make, users mix codeine with gasoline, paint thinner, iodine, hydrochloric acid and red phosphorous. Codeine, a controlled substance in the United States used to treat mild to moderate pain, is widely available over the counter in Russia.

In 2010, up to a million people, according to various estimates, were injecting the resulting substance into their veins in Russia, thus far the only country worldwide to see it grow into an epidemic, Time reports.

The drug's sinister moniker — also known as crocodile — refers to the greenish and scaly appearance of a user's skin at the site of injection as blood vessels rupture and cause surrounding tissues to die. According to reports, the drug first appeared in Siberia and parts of Russia around 2002, but has spread throughout the country in recent years.

Officials at the Washington-based National Institute on Drug Abuse told FoxNews.com in 2011 that they had not heard of the drug prior to an inquiry by FoxNews.com.

Dr. Ellen Marmur, chief of dermatological and cosmetic surgery at the Mount Sinai Medical Center in New York City, told FoxNews.com in 2011 she had never seen any cases involving krokodil, but said it reminded her of "skin popping," or when intravenous drug users inject a substance directly into their skin due to damaged veins.

"This looks to me a lot like skin popping, what drug users used to do back in the day with heroin and other drugs," Marmur said. "It just kills the skin, that's what you're seeing, big dead pieces of skin."

Those large pieces of dead skin are referred to as eschars, Marmur said, leaving the user prone to infection, amputation and other complications.

Marmur said at the time that she was concerned the drug could eventually make its way into the United States.

"It's horrible," she continued. "These people are the ultimate in self-destructive drug addiction. Once you're an addict at this level, any rational thinking doesn't apply."

Dr. Lewis Nelson, a medical toxicologist at Bellevue Hospital Center in New York, also said in 2011 that he doubted krokodil would reach the United States due to the availability of other cheap, powerful drugs such as black tar heroin and Oxycontin.

"It's not going to become a club drug, I can guarantee you that," he said.

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FoxNews.com's Joshua Rhett Miller contributed to this report.