A group of older antipsychotic drugs also referred to as neuroleptics, such as Thorazine (chlorpromazine) and Haldol (haloperidol), that work principally by blocking dopamine receptors in the brain. These medications have some potential adverse side effects such as parkinsonian symptoms (muscle stiffness, rigidity, slowed gait, and tremor) and tardive dyskinesia (involuntary lip smacking, tongue movements, and upper-extremity movements).