Dose and Dosage ─ What is the Difference?

Dose vs Dosage

Dose refers to a measured portion or a quantity of a medicine or a substance that must be taken at a time.

Dosage refers to the duration or frequency at which the medicine must be taken or administered.

We typically hear the words dose and dosage when a medical practitioner prescribes drugs for an illness. The two words have a distinct meaning but are often confused with each other. Let us break them down so that you never mix them up again.

What is the meaning of dose?

Dose refers to a measured portion or a quantity of a medicine or a substance that must be taken at a time. It does not talk about the frequency at which the drug should be taken. For instance,

The doctor prescribed a 5 mg dose of biotin.

What is the meaning of dosage?

Dosage refers to the duration or frequency at which the medicine must be taken or administered. It tells a person how many times and until when the dose must be repeated. For instance,

The doctor prescribed a dosage of 5 mg of biotin twice a day for two weeks.

Here, twice a day for two weeks is the frequency at which the drug should be taken. That’s why we use the word dosage.

Now, let us consider examples that are unique to medical writing.

Example 1:

Incorrect: We noticed that a dosage of 10 mg amphetamine did wonders on the patient.

Correct: We noticed that a dose of 10 mg amphetamine did wonders on the patient.

Example 2:

Incorrect: The patient was administered a dose of 200 mg lesinurad once daily for a week.

Correct: The patient was administered a dosage of 200 mg lesinurad once daily for a week.

We hope we have cleared up the difference between dose and dosage and made it simpler to pick the right word.