- The model described in this exercise is dose independent. When dosage is changed in such a model, which of these does not change (list all that apply)? Cmax, Cave, Cmin, Clt, Vz, T1/2
The pharmacokinetic constants Clt, Vz, T1/2 do not change.
- Assume that moderate analgesia requires a plasma concentration of 30 μg/ml. Based on the information in this module and for a dog, can an oral dose regimen for aspirin be designed to produce moderate analgesia without toxicity for an entire 12 hour dose interval?
No. A dose of 30 mg/kg produces a Cmax (PO) of 50 (toxic threshold) but effective concentrations are still maintained for only 3.5 yours.
- According to the plasma concentrations, how long was mild analgesia maintained after a 10 mg/kg oral dose? after a 20 mg/kg oral dose?
Nearly 2 hours after a 10 mg/kg dose and 3 hours after a 20 mg/kg dose.
- Which calculated value conveniently approximates the increase in the length of time achieved (duration of a particular effect) when increasing the dose from 10 to 20 mg/kg?
A 20 mg/kg dose is 2x a 10 mg/kg dose so the half-life (approximatly 1 hour) in this example nicely predicts the increase in duration of any particular effect.