According to recent reports from the Food and Drug Administration, fake versions of GlaxoSmithKline’s drug Alli were found to have dangerously high levels of the prescription weight loss ingredient sibutramine.

Sibutramine is the main ingredient in the diet drug Meridia. Although with the right dosage sibutramine can be used safely, the amount of sibutramine found in the counterfeit Alli poses a serious health risk to some individuals.

Dr. Janet Woodcock, head of the FDA’s drug unit, told reporters

“A person taking the counterfeit Alli as directed would be exposed to twice the maximum prescription dose of sibutramine every day.”

Woodcock said even healthy people exposed to the counterfeit Alli pills could experience effects including palpitations, sleepiness, anxiety, nausea and slightly elevated blood pressure.

Fake version of the diet drug have been found for sale mainly at online auctions sites like eBay.

The FDA and GlaxoSmithKline are urging consumers to check any Alli recently purchased to make sure it is the real deal. The FDA said the counterfeit Alli has:

– An outer cardboard packaging missing a `”Lot`” code.

– An expiration date that includes the month, day, and year (“06162010″), while authentic Alli expiration date includes only the month and year (“05/12″).

– Packaging in a plastic bottle that has a slightly taller and wider cap with coarser ribbing than the genuine product.

– A plain foil inner safety seal under the plastic cap without any printed words. The authentic product seal is printed with “SEALED FOR YOUR PROTECTION.”

– Contains larger capsules with a white powder, instead of small white pellets.