I Have Been On Parnate For 20 Years . It

I have been on Parnate for 20 years . it has not been working very well the last few years. I have to take Xanax 3 times a day . anxiety becoming much worse . plus brand name parnate is very expensive . I tried generic , but it makes me physically ill. my dr wants me to try Nardil , I read that Nardil is now only generic and doesn't work well . is this true , and is it expensive also , thank you