Section 2: Key Points
What We've Covered
In this section, we explored the following main points:
What We've Covered
In this section, we explored the following main points:
- Dose is the amount of a substance administered; however, several parameters are required to characterize exposure to xenobiotics, including the:
- Number of doses
- Frequency of doses
- Total time period of exposure
- The dose-response relationship helps establish causality, or that the chemical induced the observed effects; the threshold effect, or the lowest dose that induced effects; and the slope, or the rate at which effects increase with dose increases.
- Estimating doses for toxic effects involves:
- Lethal Doses/Concentrations, such as LD0, LD10, and LC50, which denote doses or concentrations that are expected to lead to death in specific percentages of a population.
- Effective Doses, such as ED50 and ED90, which denote doses that are effective in achieving a desired endpoint in specific percentages of a population.
- Toxic Doses, such as TD0 and TD50, which denote doses that cause adverse toxic effects in specific percentages of a population.
- The Therapeutic Index (TI) compares the effective dose to the toxic dose of a drug.
- The Margin of Safety (MOS) compares the toxic dose to 1% of the population to the effective dose to 99% of the population.
- NOAEL is the highest dose at which there is no observed toxic effect.
- LOAEL is the lowest dose at which there is an observed toxic effect.