Tricyclic antidepressant drug interactions with histamine and alpha-adrenergic receptors.

Tricyclic antidepressant drugs are remarkable in their therapeutic actions. When given acutely they are generally sedating. Then after a lag of 1-3 weeks, they alleviate depressive symptoms. Besides the delayed psychic energizing properties, the immediate apparent sedative actions may have importance for the relief of psychomotor agitation. This article describes influences of the drugs on histamine H1 and alpha-adrenergic receptors which may be of relevance to the energizing effects and relief of psychomotor agitation.