The dosage of a drug is determined by the effective dose (ED). All drugs are tested to measure the safety margin. When drugs are studied they take the number of people who are involved in the study and figure at the dose amount where 50% of the people studied reached a response. This is represented by ED50. They also study the LD (Lethal dose) and that is also the percentage of people who have died during the study by taking the drug. This is represented by LD50 (if 50% of people died).
The dosage of a drug is always the measurement of the concentration rather than the amount. This is because every person’s metabolism is different and the amount of time it takes to process the drug can vary. A dose-response curve is the measurement of acute and chronic toxicity. Acute toxicity is at the low end of the curve and is measured by a short term or temporary physical or psychological harm that a drug can have on the body. Chronic toxicity is the negative effects that a drug can have on the body over a long period of time.