Principles of toxicology

There are three basic and interwoven principles of toxicology  

While these principles may form much of the foundation of toxicology, when it comes to any specific substance there is likely to be controversy. Disagreement may arise on the relative importance of any one of these principles while trying to evaluate implications for public health. Exploring these principles is an essential first step before examining their application to any specific substance. This chapter will explore some of the details and issues surrounding these principles, but first it is appropriate to put them in historical context. 

Risk management combines the risk assessment with economic, political, public opinion, and other considerations to determine a course of action. These judgments seldom satisfy everyone. The principles of toxicology form the foundation for the risk assessment and ultimately for the risk management decisions. Individual and community involvement in the decision-making process is a critical part of developing sound policies to minimize risks to people and the environment. 

Oral dose = amount of material consumed (mg)/body weight (kg) 

By knowing just a couple of facts we can turn our everyday exposure of caffeine into a dose. There are approximately 100 mg of caffeine in a cup of coffee. The actual amount of caffeine in a cup of coffee depends on the coffee bean, how the coffee was prepared, and the size of the cup. An adult weighing 155 lbs (about 70 kg) consuming this one cup of coffee would receive a dose of 100 mg divided by 70 kg, or 1.4 mg/kg of caffeine. The importance of including body weight becomes clear if you consider a child who weighs only 5 kg (11 lbs). If this child consumed the same cup of coffee, the dose would be 100 mg/5 kg or 20 mg/kg, more than ten times higher than the adult. 

Other than humans. The need for expanding the focus of medicinal chemistry is met by including the principles of toxicology into all chemistry curricula. 

Toxicology is central to designing products with minimal hazard to human health and the environment. Determining whether a substance is toxic or non-toxic requires a set of metrics representing both assessment and measurement endpoints for clearly defined adverse outcomes. A cornerstone of toxicology, articulated by the medieval physician Paracelsus, states that every compound is toxic at sufficient dose in other words, the dose makes the poison . This central message has been expanded and appropriately refined to include time as a core component of the manifestation of toxicity. The idea that a chemical can be non-toxic is actually a misnomer because all chemicals are toxic at some defined dose. There is also an inherent assumption that there is a threshold dose below which adverse effects do not occur and that all chemicals are therefore non-toxic at some dose. 

Before we continue, a few definitions of terms used throughout this chapter are necessary to maintain subtle but important differences among 

The manifestation of adverse effects in biological systems is the result of perturbations of normal function or homeostasis, which involves a complex network of biochemical reactions that have evolved to maximize efficiency at the cellular, organ, tissue and whole organism level. These reactions are governed by the fundamental chemical principles that are part of typical chemistry curricula. Therefore, it is a natural extension to disclose opportunities to demonstrate the relationship between structure and toxicity. 

2 Opportunities to Embed Toxieology into the Chemistry Currieulum 

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Natural and synthetic chemicals affect every phase of our daily Hves ia both good and noxious manners. The noxious effects of certain substances have been appreciated siace the time of the ancient Greeks. However, it was not until the sixteenth century that certain principles of toxicology became formulated as a result of the thoughts of Philippus Aureolus Theophrastus Bombastus von Hohenheim-Paracelsus (1493—1541). Among a variety of other achievements, he embodied the basis for contemporary appreciation of dose—response relationships ia his often paraphrased dictum "Only the dose makes a poison."... 

It is a first principle of toxicology that no chemical substance is a poison at all concentrations toxicity occurs only when a critical concentration is reached within vital cells. Whether or not an economic poison will exert a particular deleterious effect depends on the relative rates of absorption as compared with detoxication and elimination, its inherent toxicity, and the physiologic status of the organism. 

The basic principle of toxicology, as first noted by the Swiss physician Paracelsus, is that the dose makes the poison. While this principle is easy to understand, the processes used to understand the relationships between dose and biological response, and ultimately to determine what dose of a chemical poses a reasonable certainty of no harm , are much more complicated. 

The purpose of A Small Dose of Toxicobgy is to build upon our intuitive understanding of toxicology and make it the basis for the knowledgeable and comfortable application of the principles of toxicology. Placing some form and structure around what we already intuitively know about toxicology will allow more critical analysis of not only our immediate environment but many of the current events... 

Understanding the principles of toxicology can provide the power to discover new insights into decision-making. The principles of toxicology can then be... 

Risk assessment is a complex area that requires the application of all the principles of toxicology. It is often divided into four somewhat overlapping areas ... 

Principles of Toxicology presentation material. Online. Available HTTP and follow the links to downloads and then the catalog number TF1691. 

Web site contains presentation material related to the principles of toxicology. 

People who drink caffeine have learned from experience how much to consume and thus to avoid the adverse behavioral effects of too much caffeine. Excessive consumption of caffeine is an almost perfect example of the fundamental dose-response principle of toxicology. A sudden reduction in caffeine consumption by... 

The absorption, distribution, and subsequent health effects of lead illustrate the basic principles of toxicology. Foremost is the sensitivity of children to the adverse... 

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