  Adrenergic transmission is restircted to the sympathetic division of the ANS. Three endogenous catecholamines acting as signal molecules.
| Catecholamines (CA) | Structure |
|---|---|
| Dopamine | 
|
| Noradrenaline |
|
| Adrenaline | 
|
Adrenergic Drugs or Sympathetic Drugs:
  Drugs with actions similar to that of adrenaline or that of sympathetic stimulation.
| Receptors |
|---|
| Alpha (α) Beta (β1 and β2) |
Classification (based on action):
Direct acting
Drugs which directly as agonists on alpha or beta or both adrenoreceptors.
• Adrenaline
• Noradrenaline
• Isoprenaline
• Phenylephrine
• Methoxamine
• Salbutamol
Indirect acting
Drugs which act on adrenergic neurone to release NA(noradrenaline), which then acts on the alpha & beta receptor.
• Tyramine
• Amphetamine
Mixed Action
Drugs act directly as well as indirectly.
• Ephedrine
• Mephentermine
Based on receptors - Click Here to View
