Clinical Pharmacokinetics 2 Flashcards
Maintenance doses
To maintain the plasma concentration within a specified range over long periods of therapy
At SS, dosing rate = elimination rate = CL*C/F
If intermittent doses: maintenance dose = dosing rate * dosing interval
Loading dose
Achieve a target plasma level rapidly
The dosing plan is base on
Therapeutic window
CL
Vd
Continuous IV infusion
Rate of elimination = CL * C
Css = infusion rate/CL
Loading dose = Vd*TC/F
Single IV injection
C will peak and decreae exponentially
Multiple IV injection
C increases until SS is achieved
C fluctuates about a mean
Given smaller doses at a shorter intervals reduces the amplitude of the swings in C
Css and the rate at which SS is approached are not affected by dosing frequency
Orally administered drugs
Single
Yields a more round peak
Changing the rate of absorption: rapid release vs. slow release
Slow release: delayed & lower peak, higher levels at later time > less frequent administration of drugs with short half-lives, prolong effects
Orally administered drugs
Multiple
The oscillations in C are influenced by both rate of absorption and rate of elimination