A rare side effect of seroquel is that it may cause tardive dyskinesia, a condition characterized by uncontrollable muscle spasms and twitches in the face and body. This problem can be permanent, and appears to be most common among older adults, especially women
More common side effects of seroquel may include abdominal pain, constipation, diminished movement, dizziness, drowsiness, dry mouth, excessive muscle tone, headache, indigestion, low blood pressure (especially upon standing), nasal inflammation, neck rigidity, rapid or irregular heartbeat, rash, sleepiness, tremor, uncontrollable movements, weakness.
While taking seroquel call your doctor immediately if you develop muscle stiffness, confusion, irregular or rapid heartbeat, excessive sweating, and high fever. These are signs of neuroleptic malignant syndrome (nms), a serious--and potentially fatal--reaction to the drug.