Pharmacokinetics is the process of absorption, distribution, metabolism and elimination (ADME) of drugs. Some drugs undergo zero-order kinetics (e.g. ethyl alcohol,) first order kinetics (e.g. piroxicam) and mixed order kinetics (e.g. ascorbic acid). Drugs that undergo Michaelis-Menten metabolism are characterized by either increased or decreased Km and Vmax. Hence literatures were searched with a view to translating in vitro-in vivo enzyme kinetics to pharmacokinetic/pharmacodynamic parameters for determination of enzyme inducing and inhibiting drugs inorder to achieve optimal clinical efficacy and safety. Findings have shown that theophylline, voriconazole, phenytoin, thiopental, fluorouracil, thyamine and thymidine are enzyme inducers whereas mibefradil , metronidazole isoniazid and puromicin are enzyme inhibitors. They are metabolized and eliminated according to Michaelis-menten principle. The order could be mixed but may change to zero or first order depending on drug concentrations and frequency of drug administration. Hence, pharmacokinetic-pharmacodynamic translation can be optimally achieved by incorporating newly derived Michaelis-Menten equations into pharmacokinetic parameters for clinical efficacy and safety of therapeutics.