pharmacological properties
Last reviewed 01/2023
Like the phenothiazines the tricyclics have widespread actions on the nervous system and therefore have a large number of potential side effects. It used to be believed that their common antidepressant effect was due to inhibition of re-uptake at central monoamine synapses with a subsequent increased transmitter concentration at receptor sites. However, the time of onset of anti-depressant effect does not correlate with that inhibition of reuptake, and some newer antidepressants are not potent inhibitors of reuptake. It now seems likely that they act by a secondary alteration in post synaptic receptor sensitivity and monoamine transmission.
Some tricyclic compounds are strongly anticholinergic, and have many side effects related to this, or strongly antihistaminergic or both. Most are less strongly antiserotoninergic and antiemetic (antidopamine) than chlorpromazine.