Doses

Doses refer to the amount of a substance given or received at a specific time. In medical and scientific contexts, a dose is the quantity administered to achieve a desired effect, while dosing describes the pattern of administration, including how often and for how long. The term can apply to medications, nutrients, chemicals, or radiation exposure.

Common units and expressions include mass-based measures such as milligrams (mg), micrograms (µg), and grams (g), as well as volume-based measures like milliliters (mL). Dosing is frequently expressed as milligrams per kilogram of body weight (mg/kg) or, for some regimens, milligrams per square meter (mg/m2). International Units (IU) are used for certain vitamins, hormones, and biological products. The exact dose is typically specified on product labeling and adjusted by clinicians.

In pharmacology, the dose–response relationship describes how effects change with different doses. The therapeutic window is the range between an effective dose and a dose that causes harm. Concepts such as ED50 and LD50 illustrate population-level responses in research, while individual regimens may employ fixed doses or titration to reach the desired effect.

Pharmacokinetics influence dosing through absorption, distribution, metabolism, and excretion. Route of administration, bioavailability, and a substance’s half-life determine how large a dose should be and how often it must be given. Special populations, including children, the elderly, and individuals with organ impairment, often require dose adjustments to maintain safety and efficacy.

In radiation contexts, dose concepts include absorbed dose and effective dose, measured in Gray and Sievert, respectively. Diagnostic procedures contribute to overall exposure, which is subject to regulatory limits and safety guidelines. Clinical practice uses dose-finding studies and guidelines to balance benefits and risks, with ongoing monitoring and adjustments as needed.