The US (United States) Food and Drug Administration (FDA) has warned healthcare professionals and the public about the risks of having US prescriptions dispensed in another country.  This is because foreign drugs may have identical or very similar brand names as US products but contain different active ingredients.  This could result in serious adverse effects from taking the wrong active ingredient, without any health benefits.

For example Amyben® is a UK brand name for amiodarone, which is used to treat abnormal heart rhythms.  Supplying Amyben® instead of Ambien,® a US brand name for zolpidem, a sleeping tablet, could have a serious adverse outcome. 

The FDA link below lists further examples of:
• Identical US and foreign brand names associated with different active ingredients
• Similar US and foreign brand names associated with different active ingredients

Therefore when a prescription is dispensed in a country other than where it was written, patients and healthcare professionals should be aware of the risk of incorrect medication supply.  Although the FDA advice inclines towards US products, this is also a problem in other countries.  If patients keep details of the active ingredient in their own medicine(s), this will help to avoid these errors. 

Limitations
The list of medicines in the FDA link is not comprehensive and covers prescription only medicines, not over-the-counter products. The list excludes drug products available only in a hospital setting and drugs regulated as controlled substances in the US. In addition some of the medicines may have been discontinued, or are no longer actively marketed since the publication of the information in the FDA link.

See NeLM for full disclaimer.