Contents

### **Preface XI**


Preface

adverse effects of drugs.

these steps.

Adverse effects as unwanted outcomes of drug effects occur generally when the upper threshold of therapeutic dosage range is reached. Several events and factors may lower this threshold or bring about the trespassing of the therapeutic level. The relevant events include what happens during the journey of the drug in the body, from its absorption from the site of administration, through its distribution and metabolism, to its elimination from the body. Every chapter in this book discusses and provides illustrations on the theme discussed based on authors' understanding and experience while summarizing existing knowledge. In doing so, each chapter provides a new insight that would benefit a novice as well as a seas‐ oned reader in understanding the mechanisms and risk factors involved in the occurrence of

Chapter 1 explains the linkages between pharmacokinetic processes and the occurrence of adverse effects. It provides an overview on how through direct actions and interactions drugs produce changes in absorption, metabolism and transformation, distribution in or‐ gans, and elimination from the body. These changes as moderated by individual risk factors such as the genetic makeup, sociodemographic and health status, and lifestyle factors lead

Chapter 2 dwells on the pharmacokinetics of one of the most common beverages world‐ wide, the green tea. This chapter elaborates on how food interactions affect the absorption of catechins and provides some practical illustrations that would help tea drinkers to maximize the benefits of this beverage. It further details how subsequent steps, namely, metabolism, distribution, and elimination, of the catechins take place in the mechanisms underlying

Chapter 3 illustrates the role of enzymatic transformations that result in the advent of de‐ pressive symptoms in patients suffering from chronic hepatitis C treated with interferon al‐ pha (IFN-α). In this chapter, the findings presented demonstrate how upward changes in concentration in plasma and in other compartments such as in cerebrospinal fluid of trypto‐ phan (TRP)-kynurenine (KYN) and its active metabolites [3-hydroxykynurenine (3-HK), ky‐ nurenic acid (KA), and quinolinic acid (QUIN)] are associated with the severity of depressive symptoms clinically seen as adverse effects of IFN-α. This chapter links up to the first chapter in making an exposé of one of the mechanisms by which pharmacokinetic proc‐

Chapter 4 shows the major roles of pharmacokinetics in drug development, particularly how pharmacokinetic data are useful in ascertaining the safety profile of drugs under devel‐ opment. It provides technical details of relevant steps and endpoints for each phase of a drug development; in doing so, the chapter demonstrates how pharmacokinetic studies are an important tool used to link exposure to efficacy and safety and how they assist in deter‐

Chapter 5 provides an overview on hepatotoxicity of drugs: how several drugs affect the organ that is responsible for most of the metabolism in the body, the liver. It is noted that

to the elicitation of adverse effects observed in clinical practice.

esses lead to the advent of adverse effects.

mining the dosages of marketed drugs.
