Pharmacologic features and effects of neuroleptics

Neuroleptic drugs reduce the severity and prevent the recurrence of symptoms of schizophrenia. Recent studies indicate that these drugs probably produce their antipsychotic effects by blocking dopamine receptors in the brain, although they also block acetylcholine and norepinephrine receptors. The potency of commercially available neuroleptics in blocking dopamine receptors varies widely, being related to the compound's lipid solubility. Neuroleptics predispose the patient to short-term and long-term medical hazards that must be weighed against the benefits of reduced symptom intensity, shortened psychotic episodes and lessened likelihood of recurrence of acute schizophrenic epidoses. The side effects associated with short-term therapy are either extremely rare or are treatable by dose change, medication change or the use of additional drugs. In long-term therapy the risks are more problematic in that they are sometimes irreversible. These include tardive dyskinesia, skin discoloration and corneal deposits. The clinician must consider the pattern aand severity of each patient's present and past psychotic episodes before deciding whether maintenance therapy with neuroleptics is justified. If it is, doses should be re-evaluated frequently and kept as low as possible. Concomitant administration of anticholinergic agents should be avoided if possible. Most important, the long-term administration of neuroleptics should be prescribed only for patients with schizophrenia and not for those with conditions that respond to other treatments.