Is there an interaction between Elavil 10 mg and Mestinon 15 mg?

Hello, I have just started Mestinon, 15 mg a day for the moment. I was also taking Elavil 10 mg which I had stopped and would like to start again for chronic pain. Can you tell me if there is an interaction between the two? I also take 5 mg of Nadolol and 10 mg of midodrine 3 X / day. Thank you