Effective dose equivalent definition

It is necessary to take into account the different sensitivities of various tissues and organs to the induction of deleterious health effects to the whole organism. The effective dose (E) is defined as a summation of the tissue equivalent doses multiplied by the appropriate tissue weighting factor W[. According to this definition. 

In experimental animals the effect of ephedrine administered intravenously is similar to that of epinephrine. The arterial pressure — systolic, diastolic, and mean pressure — rises and vagal slowing occurs. Compared with epinephrine, the pressor response to ephedrine occurs somewhat more slowly and lasts about ten times longer. Furthermore, it requires more ephedrine than epinephrine to obtain an equivalent pressor response. How much more depends on the species tested, type and degree of anesthesia, dose level, and individual variability of the test animal. It is, therefore, almost impossible to give a definite figure for the relative potency of ephedrine and epinephrine. It is commonly accepted that it requires about 250 times more ephedrine than epinephrine to achieve equipressor responses. 

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