Margin of Safety (MOS)

The ratio between the dose that produces a toxic effect and the dose that produces the desired therapeutic effect, quantifying the safety buffer of a drug. Commonly expressed as the ratio of TD1 (or LD1) to ED99, or as the ratio of NOAEL in animal studies to the maximum recommended human dose (MRHD) after allometric scaling. A higher margin indicates greater safety in clinical use.

示例

• Penicillin: very high MOS (low toxicity, high doses tolerated)
• Digoxin: narrow MOS requiring therapeutic drug monitoring
• Preclinical MOS = NOAEL(animal) / MRHD(human), target >= 10x