Patient Rights Treatment Decisions & Safety Print Difference Between Drug Dose and Dosage By Michael Bihari, MD Michael Bihari, MD, is a board-certified pediatrician, health educator, and medical writer, and president emeritus of the Community Health Center of Cape Cod. Learn about our editorial policy Michael Bihari, MD Updated on November 18, 2019 HOANG DINH NAM/AFP Creative / Getty Images More in Patient Rights Treatment Decisions & Safety Medical Marijuana Navigating Your Diagnosis Medical Records Managing Medical Costs Patient Advocacy Healthcare Team Hospital Stay Safety Although people often use dose and dosage interchangeably, these terms have very different meanings. By adding the suffix -age to the base dose, we are implying a regulated amount, a differentiation similar to the words' mile and mileage. Definition According to the American Medical Association (AMA) Manual of Style, the definitive guide on medical writing and style, dose and dosage each have very specific meanings. A dose refers to a specified amount of medication taken at one time. By contrast, the dosage is the prescribed administration of a specific amount, number, and frequency of doses over a specific period of time. According to the AMA, drug doses are expressed in conventional metric mass units (for example, milligrams or milligrams per kilogram) rather than in molar SI units. Moreover, certain drugs (such as insulin or heparin) may be prepared as mixtures and have no specific molecular weight, thereby precluding their expression in mass units. Although other drug dose units such as drops (for ophthalmologic preparations), grains (for aspirin), and various apothecary system measurements (eg, teaspoonfuls, ounces, and drams) may be encountered clinically, these units generally are not used. In other words, a dose is simply an amount (think weight) of a medication that is administered at one specific time. Whereas, the dosage is the dose, or amount of drug, attached to a time-frequency. A dosage guides a drug regimen. Using Tylenol as an Example Different types of Tylenol (acetaminophen) come in different doses. Choice of which specific type, or dose, of Tylenol, depends on the condition being treated. Dosages also vary by the condition being treated. Here are some different dosages of Tylenol dosages: For minor aches and pains, take 2 tablets of Regular Strength Tylenol (dose 325 mg each tablet) every 4 to 6 hours as needed. Do not exceed more than 10 tablets in 24 hours, and if the pain persists for more than a day or two, see a physician.For more severe aches and pains (like a bad headache), take 2 Extra Strength Tylenol caplets (dose 500 mg each caplet) every 6 hours as needed. Do not exceed more than 6 caplets a day. If pain persists for more than a day or two, see a physician.For arthritis pain, take 2 Tylenol Arthritis Pain caplets (dose 650 mg each caplet) every 8 hours as needed. Do not exceed more than 6 caplets a day. Was this page helpful? Thanks for your feedback! Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial policy to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. AMA Manual of Style, Oxford University Press, 10th edition, 2007. Continue Reading