Eon symptoms and conditions

I have been on lisinopril since december 08 for hypertention. My symptoms didn't appear immediatly. But as time went by, I started to notice extreme fatigue and a dry hacking cough. I ignored it at first because I was diagnosed in april of 08 with myastenia gravis. I thought it was just complications with my illness. So I told my internist about my symptoms and of course at first he wanted to blame it on allergies and sinus. I have never been so bothered with allergies in all of my 39 years so I new it had to be the pill. I have recently been to my doctor with continued complaints so he has taken me off of the pill and wants to see me back in 2weeks.