VPT 311: General and Systemic Veterinary Pharmacology (2+1)

DRUG ACCUMULATION

• In first order kinetics, on repeated dose within the complete elimination of the previous dose, drug accumulates in the body.
• Plateau (steady state) achieved within 4 –5 half lives. The C_ss is the average of min. and max. of the steady state or the plateau state.
• For long term therapy, it is aimed to have the therapeutic conc. as C_ss
• Target C_p = C_ss
• Dose rate = (target C_p x Cl ) (mg / kg per time)/F 
• In some cases immediate higher dose is to be given (otherwise target C_p will be reached only after 4 – 5 half lives)
• In such cases, Loading dose = (target C_p x V_d )/F