It inhibits the activity of such diverse agents as histamine, 5-hydroxytryptamine, and acetylcholine. Nevertheless, caution is indicated in the co-administration of TCAs with any of the SSRIs and also in switching from one class to the other. Subscribe to our popular newsletter containing regular roundup of medication news, alerts and new drug approvals. Nortriptyline and interpersonal psychotherapy as maintenance therapies for recurrent major depression: randomized controlled trial in patients older than 59 years Comment: JAMA: Journal of the American Medical Association Vol osta nortriptyline online 281 20 May 1999, 1891.