Been on brimonidine 6 wks or so. Just realized above symptoms were not caused by what I thought. Googled and found above symptoms as well as several others I also have - dizzy, light-headed, headaches, jittery in chest, depressed, weepy, sleepy, etc.. Last dose pm last night. Called ophthalmologist this a.m.- not in until Monday. Daughter, Nurse Practitioner, checking for me as well. Said half life is 3 hours. Don't know what that means pertaining to the side effects' longevity. Healthy, quite active, 73 year old female. Also on Lantanaprost. Have had glaucoma surgery on right eye. One drop in left eye 1X daily only. On no other medications.