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Merck Manual
Veterinary Manual
The trusted provider of veterinary information since 1955

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VETERINARY PET
Effect of competitive antagonist on dose-response relationship
drug-action-ferguson-figure-6-sized
Effect of competitive antagonist on dose-response relationship

    Dose-response curve for an agonist drug with and without the presence of a competitive antagonist. In the presence of a competitive antagonist, achievement of the same effect as originally achieved by the EC50 of agonist by itself requires an agonist concentration that is 100-fold higher (indicated by arrows).

Courtesy of Dr. Duncan C. Ferguson.

In these topics
Drug Action in Animals : Pharmacodynamics

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