Single intravenous dosing

Single intravenous dosing

When a drug is administered by an intravenous injection, all the drug enters the systemic circulation. It is possible to determine how much drug is necessary to reach a desired serum concentration.
For example: for the administration of digoxin to a 70 kg patient. What intravenous loading dose should be given to reach a target plasma level of 1,5 ng/ml?
Population parameters are: Vd = 7,3 L/kg; Therapeutic plasma level = 0,5-2 ng/ml;

Dose / V = Cmax or Dose = C 12.800000190734863px; caret-color: #000040; color: #000040; font-family: Verdana, Arial; background-color: #e4eaff;">maxx V

Vd = 7,3 L/Kg x 70 Kg = 511 L
Dose = 1,5 ng/ml x 511 L = 0,766 mg

See how dosing variations give different concentration-time curves here (module 1 for intravenous dosing).


What is the inital plasma concentration (C0) when 10 mg of a drug (Volume of Distribution = 3 L/kg) is administered to a 70 kg patient?