What is the formula used to determine the safety of a drug related to its effective and lethal doses?

The formula used to determine the safety of a drug in relation to its effective and lethal doses is known as the therapeutic index. The therapeutic index is calculated by comparing the dose that produces a therapeutic effect (effective dose) to the dose that produces toxicity or lethal effects (lethal dose). A higher therapeutic index indicates a greater margin of safety, meaning there is a larger difference between the effective and toxic doses, which suggests that the drug can be used safely at higher doses.

In contrast, while effective dose refers specifically to the dose required to achieve the desired therapeutic effect, it does not account for safety. The safety margin is also related but reflects the additional buffer between the effective and toxic doses without providing a clear quantitative relationship. Dosage range describes the spectrum of doses at which a drug may be effective but is not specifically about the relationship between effectiveness and safety.

Understanding the therapeutic index is crucial for healthcare providers as it aids in prescribing dosages that maximize therapeutic benefits while minimizing the risk of adverse effects or toxicity.