Hi & Welcome. Yes, it may cause harmful interaction if taken together. When taken together with Lamotrigine, the antidepressant Venlafaxine may increase the side effects such as dizziness, drowsiness, confusion, difficulty concentrating, impairment in thinking, and motor coordination resulting in tripping or losing balance while walking or moving with difficulty. Consult your treating doctor for a possible dosage adjustment of these medications. Also avoid activities requiring mental alertness such as driving, swimming or operating hazardous machinery if any. Do not stop using any medications without first talking to your doctor. There s no documented harmful interactions between the other prescribed medications. Hope these answer your queries. A feed back is appreciated.