Threshold dose

Threshold dose is the minimum amount of a drug or chemical that results in a detectable physiological or biological response. This concept is fundamental in toxicology and pharmacology, as it helps determine the safety and efficacy of drugs and chemicals.

Definition

The threshold dose is defined as the lowest dose of a substance at which a specified measurable effect is observed and below which it is not observed. This concept is used in risk assessment to identify the dose at which a substance may begin to pose a risk to human health.

Determination

Determining the threshold dose involves conducting dose-response studies, where varying amounts of a substance are administered to a test population, and the responses are observed and recorded. The dose at which a response is first observed is considered the threshold dose.

Importance in Pharmacology

In pharmacology, the threshold dose is crucial in drug development and testing. It helps in determining the minimum effective dose (MED) of a drug, which is the smallest dose that will produce a therapeutic effect. It also aids in establishing the maximum tolerated dose (MTD), which is the highest dose that will produce desired effects without causing unacceptable side effects.

Importance in Toxicology

In toxicology, the threshold dose is used to establish safety guidelines and exposure limits for potentially harmful substances. It is used to determine the No Observed Adverse Effect Level (NOAEL) and the Lowest Observed Adverse Effect Level (LOAEL), which are used in risk assessment and regulatory decision-making.

See Also

• Dose-response relationship
• Toxicity
• Pharmacodynamics
• Pharmacokinetics