Welcome all to IS PHARMACOLOGY DIFFICULT Podcast ! I am Dr Radhika Vijay, in today's episode, I will be again talking about a new subtopic under the main head of Pharmacokinetics. To start the discussion, I will talk firstly about repeated drug administration leads to attainment of steady state plasma concentration denoted as "Cpss", where elimination balances the input.It is given by equation as follows: Cpss=Dose rate/ Clearance. Going deep in this concept, a little research would give another relation between dose rate and Clearance, dose rate needed to achieve target steady state plasma concentration, is given by Equation: Dose rate= Target Cpss X Clearance. Now again I will modify this formula for fraction of dose which reaches systemic circulation in active form, then this equation becomes as follows: Dose rate = (Target Cpss X CL)/F. This relationship is linear on graph for drugs following first order kinetics, not for drugs following zero order kinetics. In case of Michaelis Menten kinetics, an increase in dose beyond steady state plasma concentration goes out of proportion , then a new formula is derived which is given as: Rate of drug elimination= (Vmax X C)/(Km+C), where C is plasma drug concentration, Vmax is maximum rate of drug elimination, Km is plasma concentration at which elimination rate is half maximal. All in all giving you three equations of the day, too much for learning! Till next episode, do follow me here, stay tuned, do rate and review on ITunes, Apple podcasts, Happy learning! Thank you!