At the beginning of the year, the mail order drug co. I get my imipramine from, changed manufacturers (Lupin). I used to take a small green pill and now take a larger burnt orange pill. About 2 months ago, I started having occasional panic attacks while driving. The last 2 weeks I've had them daily. Is it possible that by switching manufacturers of imipramine, I'm not having the same results as my old green pill? My old pills worked great!