Laadimisannus

Laadimisannus is an Estonian term used in pharmacology to describe the initial, higher dose of a drug given at the start of therapy to rapidly achieve therapeutic plasma concentrations. It denotes the loading dose intended to bring drug levels to the target range quickly, after which a maintenance dose is used to sustain those levels.

The main purpose of a loading dose is to overcome a drug’s pharmacokinetic properties that would otherwise delay therapeutic effect. It is particularly relevant for drugs with a large volume of distribution, long half-life, or when rapid onset of action is clinically important. By achieving the desired concentration promptly, loading doses can shorten the time to clinical efficacy and improve treatment outcomes.

Calculation and administration of a loading dose are based on pharmacokinetic principles. A commonly cited relation is LD = (C_target × Vd) / F, where C_target is the desired plasma concentration, Vd is the volume of distribution, and F is bioavailability (with F = 1 for intravenously administered drugs). For oral dosing, F is typically less than 1, and the calculation accounts for absorption. The loading dose is usually followed by a maintenance dose to sustain therapeutic levels, adjusted for patient-specific factors.

Clinical use of a loading dose requires careful consideration of patient factors such as renal and hepatic function, age, weight, and potential drug interactions. Monitoring of drug levels and clinical response helps guide subsequent dosing adjustments to balance efficacy and safety.

See also: maintenance dose, pharmacokinetics, loading dose, dosing regimen.