DOSAGE definition: the administration of medicine in doses. See examples of dosage used in a sentence. Dosage is the predetermined amount and rate of administration of a drug for a patient. According to the AMA (American Medical Association) Manual of Style, Dosage is the prescribed administration of a predetermined amount, number, and frequency of doses of drug over a specific period of time. 1. the quantity of medicine etc to be taken at one time. In pharmacology and medicine, dosage refers to the prescribed regimen for administering a medication or substance, encompassing the amount, frequency, and duration of use. [1] A dose is the amount of a substance administered at one time, while dosage refers to the frequency and size of doses over a period. DOSAGE definition: 1. the amount of medicine that you should take at one time: 2. the amount of medicine that you…. Learn more. A dose is the amount of a drug taken at one time, while dosage refers to how often and how long you'll take the drug for. Following guidelines for dose and dosage can ensure you get effective treatment. Strengthen your mastery of dosage calculations and clinical decision-making with these related guides. Each article builds on the skills you learned here and helps you move confidently through increasingly complex medication math. Find dosage information for over 5,000 prescription and over-the-counter medications, based on FDA-approved labeling and established drug reference sources. The meaning of DOSAGE is the addition of an ingredient or the application of an agent in a measured dose.