Medicines may have up to three different names:
A chemical name or formula
A generic name
A brand or trade name
For instance, Advil is a brand for ibuprofen – a non-steroidal anti-inflammatory drug (NSAID). In this case, ibuprofen is the generic name, and Advil is one of several trade names.
Trade names may vary from country to country. In the US, ibuprofen is also sold under other names (e.g., Motrin and Midol). In Spain, however, ibuprofen is mostly sold under its generic name (ibuprofeno).
Generic names are official and non-proprietary. For example, the USAN Council assigns unique names to medicines marketed in the US based on their pharmacological or chemical relationships.
People, including healthcare professionals communicating with patients, often refer to medicines by their generic or trade names.
Chemical names are generally only used by chemists, pharmacists, and researchers. The chemical name for the example above is p-isobutylhydratopic acid.
While generic names often have equivalents in other languages, trade names may be restricted to a single country. For instance, if somebody from a Spanish-speaking country came to the US and referred to a drug by a brand name that only exists in their country of origin, that could pose a translation challenge.
That's why you need a skilled English into Spanish translator specializing in medical translation for similar cases. Feel free to contact me if you have any questions!