Joseph Kuo1, Hai-Gwo Hwu. 1. Department of Psychiatry, Lotung St. Mary's Hospital, Ilan, Taiwan. kuo2084@yahoo.com.tw
Abstract
OBJECTIVE: Schizophrenia is a chronic disease that is treated with dopamine antagonists. These drugs can produce intolerable side effects through their blockade of central nervous system dopamine receptors unrelated to schizophrenia. The atypical antipsychotic aripiprazole, a dopamine receptor partial agonist, has mixed agonist-antagonist effects. Its partial agonism is said to protect the patient from the side effects caused by full antagonists at the same time that its antagonism treats the schizophrenia effectively. CASE: We report a case in which a low dose of the full antagonist haloperidol, added to aripiprazole, improved antipsychotic efficacy in a 41-year-old man diagnosed with undifferentiated schizophrenia. RESULT: A 15-mg/d aripiprazole/7.5-mg/d haloperidol regime in this patient improved all previous psychotic symptoms and caused no adverse side effects. The patient's final prolactin concentration using this combination was normal. CONCLUSION: Further studies are warranted to confirm this observation and to determine the mechanism through which a carefully titrated combination of a full antagonist with a partial agonist can cause such improvement.
OBJECTIVE:Schizophrenia is a chronic disease that is treated with dopamine antagonists. These drugs can produce intolerable side effects through their blockade of central nervous system dopamine receptors unrelated to schizophrenia. The atypical antipsychotic aripiprazole, a dopamine receptor partial agonist, has mixed agonist-antagonist effects. Its partial agonism is said to protect the patient from the side effects caused by full antagonists at the same time that its antagonism treats the schizophrenia effectively. CASE: We report a case in which a low dose of the full antagonist haloperidol, added to aripiprazole, improved antipsychotic efficacy in a 41-year-old man diagnosed with undifferentiated schizophrenia. RESULT: A 15-mg/d aripiprazole/7.5-mg/d haloperidol regime in this patient improved all previous psychotic symptoms and caused no adverse side effects. The patient's final prolactin concentration using this combination was normal. CONCLUSION: Further studies are warranted to confirm this observation and to determine the mechanism through which a carefully titrated combination of a full antagonist with a partial agonist can cause such improvement.