Can Nortiptyline Be Taken Along With Gabapentin, Lorazepan And Chemo Treatment?

Hi there I have beenprescribed nortiptyline and I am concerned the GP has not taken all factors into consideration. I am presently on 1800 mg per day of gabapentin, 1mg lorazepan sleeping tablet and 5/7/5mg prenisolone daily. I am also on chemotherapy treatment every 2 months of rituxumab. Can you see any problems?