Effective dose (pharmacology)
In pharmacology, an effective dose (ED) or effective concentration (EC) is the dose or concentration of a drug that produces a biological response.[1][2] The term "effective dose" is used when measurements are taken in vivo, while "effective concentration" is used when the measurements are taken in vitro.[3]
The importance of determining the therapeutic range of a drug cannot be overstated. This is generally defined by the range between the minimum effective dose (MED) and the
ED50
The median effective dose is the dose that produces a quantal effect (all or nothing) in 50% of the population that takes it (median referring to the 50% population base).[6] It is also sometimes abbreviated as the ED50, meaning "effective dose for 50% of the population". The ED50 is commonly used as a measure of the reasonable expectancy of a drug effect, but does not necessarily represent the dose that a clinician might use. This depends on the need for the effect, and also the toxicity. The toxicity and even the lethality of a drug can be quantified by the TD50 and LD50 respectively. Ideally, the effective dose would be substantially less than either the toxic or lethal dose for a drug to be therapeutically relevant.
ED95
The ED95 is the dose required to achieve the desired effect in 95% of the population.
In anaesthesia, the term ED95 is also used when referring to the pharmacology of neuromuscular blocking drugs. In this context, it is the dose which will cause 95% depression of the height of a single muscle twitch, in half of the population. Put another way, it is the ED50 for 95% reduction in twitch height.[7] The single twitch response occurs when a nerve stimulator is used to stimulate the ulnar nerve, and the degree of twitch of the adductor pollicus muscle is measured. A more accurate nomenclature when used in this way would be "ED5095".
See also
- List of abbreviations used in medical prescriptions
- Certain safety factor
- LD50
References
- PMID 7569511.
- ^ Street, Farnam (2014-02-13). "The Minimum Effective Dose: Why Less is More". Farnam Street. Retrieved 2023-05-23.
- OCLC 903083639.
- ^ "Woman Dies After Water-drinking Contest". NBC. Associated Press.
- ^ ISBN 978-1-4398-2246-3.
- ISBN 978-1-4557-0876-5.