Antidepressant Medications, Tricyclics
Dietary fiber has been shown to lower the blood levels and effectiveness of tricyclic antidepressant medications such as amitriptyline, doxepin, and imipramine in three patients. Reduced dietary fiber intake increased the blood levels and improved symptoms in these patients. Individuals currently taking tricyclic medications should consult a healthcare provider before increasing fiber intake.


According to

http://www.medformation.com/ac/CAM.nsf/interactions_supplements/Fibercs.html