What is the difference between ‘dose’ and ‘dosage’?

Solution 1:

They can often be used interchangeably. A 'dose' is a countable unit of it (1 spoonfuls, etc). The uncountable 'dosage' is what the doctor prescribes.

The following extract from MedLinguistic explains the difference:

• Despite repeated emphasis upon the distinction between dose and dosage, these two terms continue to baffle us. As we’ve often been told, dose refers to a specified amount of medication taken at one time.

• In the preferred use of dosage, however, the term refers to the administering of a specific amount, number, and frequency of doses over a specified period of time. Dosage implies duration: a “dosage regimen” is a treatment plan for administering a drug over a period of time.