What is the therapeutic index used for in pharmacology?

The therapeutic index is an important concept in pharmacology that measures the safety of a drug. It is defined as the ratio between the toxic dose and the therapeutic dose of a medication. A high therapeutic index indicates that there is a wide margin between the effective dose and the dose that can cause harmful effects, suggesting that the drug can be administered safely to patients with less risk of toxicity. Conversely, a low therapeutic index denotes that small increases in dose can lead to toxicity, which requires careful monitoring and potentially more stringent dosing guidelines.

Understanding the therapeutic index is crucial for healthcare providers when prescribing medications, as it informs decisions on dosing and the potential risks involved, ultimately guiding safer pharmacological practices. This is why the first option is the correct answer, as it directly relates to the assessment of drug safety in clinical use.