dose

A dose is the amount of drug given at one time to produce a desired effect — the two tablets you take now, the 5 mL of syrup you measure for a child, the volume drawn into a syringe. It is the practical answer to the question how much.

The right dose is a careful balance. Too little and the drug does nothing; too much and it harms. The gap between an effective dose and a toxic one is called the therapeutic window, and for some drugs it is dangerously narrow, demanding precise dosing and sometimes blood-level monitoring.

Dose depends on more than the drug. Body weight, age, kidney and liver function, other medicines and the route of administration all influence how much is needed. Pharmaceutics supports correct dosing by designing dosage forms that deliver the intended amount reliably, such as unit doses that package one dose at a time.