ED50 median effective dose

FIGURE 1.11 a) The concept of antagonism or potentiation of pharmacologic effects, b) Drugs with higher therapeutic indices are safer. TI = therapeutic index, LD50 = median lethal dose, ED50 = median effective dose. 

KEY A = Based upon the amount of drug added to the volatilization chamber. B = Free base volatilized at 250%C. C = Volatilized at 275%C. D = Volatilized at 200 %C. ED50 = Median effective dose. 

Piegorsh, W. (1989). Quantification of toxic response and the development of the median effective dose (ED50)—a historical perspective. Toxicol. Indust. Health. 5 55-62. 

Weil, C. (1952). Table for convenient calculation of median effective dose (LD50 or ED50) and instructions in their use. Biometrics 8 249-263. 

Potency is compared using the median effective concentration (EC50) or median effective dose (ED50), the meanings of which are subtly different. 

The dose, symbolized by ED, producing a desired effect by a substance. The symbol is usually followed by a subscript number indicating the dose that has the desired effect on a certain percentage of the tested population. The median effective dose is ED50. 

In order to compare the safety and efficacy of drugs and their formulations, the therapeutic index, an estimate of therapeutic effects in relation to side effects, is often used (Figure 5.9B).The dose or concentration of a drug needed to ehcit a therapeutic effect in 50% of the population (median effective dose) is called the ED50. Typically a median lethal dose or LD50 is characterized for each drug in relevant experimental animals. The relationship of median lethal dose and effective dose comparison is the therapeutic index ... 

The quantal dose-effect curve is often characterized by stating the median effective dose (ED50), which is the dose at which 50% of individuals exhibit the specified quantal effect. (Note that the abbreviation ED50 has a different meaning in this context... 

ED50 is the median effective dose, a measure of response in the animal (other than death) the median effective dose is that at which 50% of the desired effect is achieved in 50% of the animals tested. Values for EDS0 are known and quoted for acute oral values. 

A quantal dose-effect relationship can also be graphically displayed as a cumulative dose-effect curve/ in which the cumulative percentage of individuals experiencing an effect is plotted as a function of the threshold dose. The normal frequency distribution in Figure 18.11 A takes on a sigmoidal shape when the same data are plotted as a cumulative dose-effect curve (Figure 18.1 IB). The median effective dose (ED50) for the quantal dose-effect relationship is the dose at... 

In pharmacology, the EflFective Dose (ED) is the minimal dose that produces the desired effect of a dmg. The effective dose is often determined based on analyzing the dose-response relationship specific to the drug. The dosage that produces a desired effect in half the test population is referred to as the median effective dose ED50, that is, the amount of drug that produces a therapeutic response in 50% of the people taking it. 

These curves plot the percentage of a population responding to a specified drug effect versus dose or log dose. They permit estimations of the median effective dose, or effective dose in 50% of a population—ED50. 

As well as mortality, other types of response can be plotted against dose. Similarly a median effective dose can be determined from these dose-response curves such as the ED50 where a pharmacological,... 

The dose required to produce a specified intensity of effect in 50% of individuals is known as the median effective dose or ED50 (Fig. 3.5). If death is the specified effect, the median effective dose is termed the median lethal dose or LD50. The ratio LD50/ED50 leads to the therapeutic index (or therapeutic ratio). This index has limited usefulness since it cannot be calculated for man and data relating to one species cannot reliably be transferred to another. 

The rapid bactericidal effect of cefaclor against susceptible organisms at levels at or near the inhibitory concentrations is well documented (Sanders, 1977 Silver et al., 1977). The comparative efficacy of cefaclor, cephalexin, and ampicillin in protecting mice from lethal effects of bacterial infections intraperitoneally administered is shown in Table IX. Note a 10-fold advantage in median effective dose (ED50) for cefaclor over cephalexin against certain strains of S. pneumoniae and the activity of cefaclor against strains of H. influenzae resistant to ampicillin. 

The median effective and toxic doses are used to determine the therapeutic index (TI).24 The TI is calculated as the ratio of the TD o to the ED50 ... 

The therapeutic index (Figure 1.11) deals with the ratio of lethal doses to 50% of the population (LD50) over the median minimum effective dose (ED50). 

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