Properties of the TCA class of drugs
Tricyclic antidepressants (TCAs) are an important group of antidepressants in clinical use; they include imipramine, clomipramine, amitriptyline and desipramine. The main effect of TCAs is to block the uptake of monoamines by nerve terminals, by competing for the binding site of the carrier protein. Most TCAs are non-selective and inhibit noradrenaline and 5-HT uptake to a similar degree, but have much less effect on dopamine uptake. TCAs produce a number of side effects, mainly due to interference with autonomic control, including atropine-like effects (muscarinic cholinergic receptor block), postural hypotension (α1-adrenergic receptor block) and sedation (H1 histamine receptor block). Poor dental health, due to effects of TCAs on salivary secretion, is a common problem among middle-aged and elderly patients.
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References
Drugs used in affective disorders. In: Pharmacology, 4th edition. Rang HP, Dale MM and Ritter JM. Edinburgh, UK: Harcourt Publishers Ltd, 2001:550–565.
Antidepressants and mood stabilizers. In: Essential psychopharmacology. Neuroscientific basis and practical applications. Stahl SM. Cambridge, UK: Cambridge University Press, 1996:131–166.