ADRENERGIC DRUGS

The adrenergic or sympathomimetic drugs are agents that mimic the responses obtained as a result of stimulation of the sympathetic or adrenergic nerves. Most of these compounds contain an intact or a partially substituted amino (NH2) group.

Adrenaline is a hormone which is secreted by adrenal medulla. It exerts various pharmacological actions like cardiac  stimulation, increase in blood pressure, constriction of smaller arterioles, relaxation of bronchial :les and stimulation of central nervous system. These actions stimulate the effects which are produced by the stimulation of adrenergic nerves. Adrenergic agents exert similar actions.

Adrenergic drugs are used for raising blood pressure (e.g. noradrenaline, metaraminol), as central stimulants (e.g. amphetamine), as smooth muscle relaxants (e.g. adrenaline, saibutamol), in local vasoconstrictor effect (e.g. adrenaline, naphazoline, phenylephrine) and for suppressing the appetite (e.g. phenteramine). Adrenergic compounds contain hydoxyl groups substituted in the 3-and 4-positions of the benzene ring (e.g. catecholamines). Some of the compounds lack the hydroxyl groups and known as non-catecholamines.