Common side effects of the Cosopt medicine are as follows. There are usually temporary and may leave once the treatment is finished. Blurred or double vision, Burning, itching or stinging in the eye, May cause a bitter or unpleasant taste in the mouth Major side effects ofdorzolamide 2 eye dropsare as follows. If you notice any of the below-mentioned side effects, consult a doctor immediately. Swelling or redness in the eyes, Trouble breathing, wheezing, rapid heartbeat., Drainage or crusting on the eyes., Pain in the eye or discomfort, May cause an allergic reaction such as shortness of breath, skin rash, hives, etc.