tca
3 interactions related to tca
amitriptyline + st. john's wort
St. John's wort induces the cytochrome P450 enzymes (and the P-glycoprotein transporter) that clear amitriptyline, measurably lowering amitriptyline blood levels and reducing its antidepressant and pain-relieving effect. Because both also raise serotonin signaling, combining them adds a theoretical risk of serotonin syndrome. The net effect can be a weaker antidepressant plus an added safety concern.
alcohol + amitriptyline
Amitriptyline is a sedating tricyclic antidepressant with strong antihistaminic and anticholinergic effects. Combining it with alcohol — also a central nervous system depressant — produces additive drowsiness, impaired coordination and reaction time, and a greater risk of falls and accidents. The FDA label warns explicitly that amitriptyline may enhance the response to alcohol.
nortriptyline + st. john's wort
St. John's wort induces the liver enzymes (chiefly CYP3A4, via the pregnane X receptor) that help clear nortriptyline, which can lower nortriptyline blood levels and weaken its antidepressant effect. The herb also adds serotonergic activity, which gives an additive, theoretical increase in the risk of serotonin syndrome.