The U.S. Food and Drug Administration (FDA) is warning that drugs sold abroad may have the same brand name or similar sounding names as domestic drugs, but have completely different ingredients.

The agency said taking the wrong medication can have serious consequences, reports Health Day News.

The FDA studied drugs in 29 countries and found multiple cases of similar-sounding drug names resulting in serious health problems.

For example, in Jan. 2004, a patient traveling in Serbia ran out of Dilacor XR, which treats high blood pressure. He went to a local pharmacy and received digoxin.

In Serbia, Dilacor is a brand name for digoxin, which is used to treat heart failure and abnormal heart rhythms. The patient ended up being hospitalized with life-threatening drug toxicity after he returned to the U.S., according to an Institute for Safe Medication Practices report.

In the United States, the drug Ambien is a popular sleep aid, however in the United Kingdom, a similar sounding-drug called Ambyen is the brand name for amiodarone, which is used to treat abnormal heart rhythms.

"If you're traveling abroad, bring enough medication and then a little bit more, in case your travel plans are changed," says Ilisa Bernstein, director of pharmacy affairs at the FDA.

"If you lose your medication while you are traveling, or run out, get advice from a qualified medical expert, because going to the pharmacy, you could get the wrong drug," she adds.