Difference Between Dosage & Dose

The word "dose" refers to a quantity of medicine to be taken at one time, according to the National Institutes of Health. However, the word "dosage" indicates the amount and other stipulations of a medicine to be taken, according to The Merriam-Webster Dictionary.

Meanings

• According to eSpindle Learning, an online source for English vocabulary, the suffix "age" added to a word denotes an action or process. For example, a pharmacist may prepare one dose of a medicine, but a patient buying the medicine may ask, "What is the dosage?" The patient wants to know not only what quantity of the medicine to take but also the frequency and duration of the treatment period. When the pharmacist prepares a "dose," this refers only to the unit measure in the prescription.

Considerations

• Correct use of the suffix "age" doesn't allow the two words to be used interchangeably. It would be grammatically incorrect to use the word "dosage" if referring only to a single measure of quantity, since the suffix itself implies an action or process.

Analogy

• Consider that the speed of a moving car is given in "miles" but a person may wish to know the "mileage" of a vehicle before buying it. "Mileage" indicates how many miles the car was driven, or "gas mileage" denotes how many miles the car will travel per gallon of gas. Similarly, the word "dosage" gives more information than just the unit of measure.

Correct Use

• Use "dose" when referring to the single unit serving of medication to be taken at one time. A "double dose" would be twice the single unit measure. Use "dosage" when discussing both the quantity and the regularity of use of the medication.