To create a universal language, to avoid mistakes and to make life easier for those patients who travel, the World Health Organisation (WHO) set up the system of INN in the 1950's.

The use of the INN by the doctor, pharmacist and patient allows each one of them to fully understand the contents of the medication that is prescribed, dispensed and used. This clarification means that the patient is less likely to take a double dose (or more) by mistake, for example, by taking the same substance under two different brand names, either as self medication, or through a prescription from another doctor. Indeed, severe overdoses have been reported, for example with medicines for hypertension such as diltiazem or verapamil. For those patients allergic to a particular medicine, the use of the INN helps them to avoid taking this medicine under a different brand name (without knowing) and therefore avoids the risk of a serious problem. Amoxicillin, a penicillin-based antibiotic, is commonly available under several brand names that are a cause for confusion.

By using the INN you can make savings when you organise your medicine cabinet. Not only can you compare the prices of medicines with their generic equivalents, but also avoid buying several medicines that contain the same substance.

For those curious enough, the INN is full of information. It contains a prefix and/or a suffix indicating the therapeutic family of the substance. Thus, people can better understand the kind of medicine used, what it is used for, when and why to take it or why not to take it.