GC: n

S: https://www.ncbi.nlm.nih.gov/pubmed/5914087 (last access: 30 June 2017); https://www.ncbi.nlm.nih.gov/pubmed/2447738 (last access: 30 June 2017).

N: 1. 1867; see dose + -age, perhaps on model of French dosage (1812).
2. Several meanings depending on field and context:

• The addition of an ingredient or the application of an agent in a measured dose.
• The presence and relative representation or strength of a factor or agent.
• Dose (to give a dose to; especially: to give medicine to; to divide into doses; to treat with an application or agent).
• The giving of a dose: regulation or determination of doses.
• An exposure to some experience in or as if in measured portions.

3. Dose vs. dosage: 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. One way to absolutely never forget the distinction between dose and dosage is to focus on the meaning of the suffix –age in dosage. Dose will then be understood by default.

S: 1. OED – http://www.etymonline.com/index.php?term=dosage (last access: 30 June 2017). 2. MW – https://www.merriam-webster.com/dictionary/dosage; https://www.merriam-webster.com/dictionary/dose (last access: 30 June 2017). 3. http://www.medlinguistics.com/didyouknow.asp (last access: 30 June 2017).

SYN:
S:

CR: dose, pharmacology, posology.