Receptor selectivity

Drug selectivity

In drug treatment, selectivity is very important in order to have the desired drug effect and to avoid possible adverse effects. This example shows the affinity of 3 different beta-adrenergic antagonists for the β1 and β2 receptor, respectively. It can be deduced from the graphs, that propranolol is not selective: it has the same affinity for both β1 and β2. Metoprolol, however, is selective for β1: it has a high affinity for β1 and a low affinity for β2. Butoxamine is selective for β2 and not for β1.