The most common side effects include dry mouth, blurred vision and constipation, dizziness or lightheadedness, and weight gain. Sometimes atypical antipsychotics can cause problems sleeping, extreme tiredness and weakness. For some atypical antipsychotics, long-term side effects include tardive dyskinesia (TD), a disorder characterized by involuntary movements most often affecting the mouth, lips and tongue, and sometimes the trunk or other parts of the body such as arms and legs. Taking these drugs over a long period of time — usually many years — increases the risk of long-term side effects.
Convulsions, apprehension, and ataxia have been reported with quinidine therapy, but it is not clear that these were not simply the results of hypotension and consequent cerebral hypoperfusion in patients being treated for cardiovascular indications. Acute psychotic reactions have been reported to follow the first dose of quinidine, but these reactions appear to be extremely rare. Other adverse reactions occasionally reported with quinidine therapy include depression, mydriasis , disturbed color perception, night blindness, scotomata, optic neuritis, visual field loss, photosensitivity , keratopathy, and abnormalities of skin pigmentation .