• Antidepressant drugs are effective in the treatment of pathologic depressive states

• Include 4 classes: tricyclic, tetracyclic and bicyclic antidepressants and monoamine oxidase inhibitors

• Elevate mood of patient though not strictly CNS stimulants

TRICYCLICS

eg Amitriptyline, Doxepin, Clomipramine

• Given orally

• First line antidepressant

• Block neuronal uptake of amines such as NAd & Serotonin and thus effectively increase the effective concentrations of these drugs in the brain

• In addition to antidepressant activity have anticholinergic, antiserotonin, antihistamine, hypothermic & antiemetic actions

• Adverse Reactions:

Anticholinergic: dry mouth, blurred vision, constipation, urinary retention, [exacerbated by other anticholinergics]

Cardiovascular: postural hypotension, prolonged A—V conduction, tachycardia, ectopics

Will potentiate activity of biogenic amines such as noradrenaline

MONOAMINE OXIDASE INHIBITOR

eg Phenelzine

• Second line antidepressant

• Given orally

• Inhibit enzyme monoamine oxidase (MAO) — MAO is responsible for breakdown of amines such as serotonin & noradrenaline; if MAO is inhibited then serotonin & other catecholamines accumulate in the brain

• Adverse Reactions:

Hypertension: hypertensive crises may precipitate after ingestion of certain foods & drugs:

Drugs: adrenaline, noradrenaline, ephedrine, phenylephrine, metaraminol, isoprenaline, dopamine, tyramine

Food: cheese, vegemite, red wine