Hi, thanks for asking in Healthcare Magic. Unless you name the drugs specifically it is difficult to tell the exact drug interactions. Although you have not given the drugs list, you have mentioned the drug groups and so let me try to tell you the common interaction of these group of drugs. Most of the anti epileptic drugs (drugs taken for Grand Mal, Focal seizures) are enzyme stimulants ie., they stimulate the metabolism (destruction or degradation) of the drugs taken along with them. This results in reduced action of the drugs given with them resulting in reduced therapeutic benefit of those drugs. Anti depressants can be either TCA (tricyclic anti depressants) like Amitriptyline or SSRI (selective serotonin reuptake inhibitor) like Escitalopram. TCA increases plasma concentration of anti epileptic drugs like Phenytoin (given for Grand Mal) by displacing it from its binding site (plasma proteins). Also, TCA reduces the gastric motility and inhibit the absorption of all the drugs. SSRI inhibits metabolism (enzyme inhibitor) and increases the level of co administered drugs increasing their side effects. Generally vitamins are safer. B12 and Folic acid given in megaloblastic anemia may not cause drug interaction but iron preparations given in iron deficiency anemia can result in either constipation or diarrhea interfering with the intestinal absorption of the co administered drugs. I hope this helps.