The use of first generation versus second generation antipsychotics as add-on or as switch treatment and its effect...

Some psychotropic drugs are connected with prolongation of the QT interval, torsade de pointes and sudden death. Recent data suggest that with regard to this adverse effect, the atypical antipsychotic drugs are no safer than the older drugs. The purpose of this study is to evaluate the different use of first generation versus second generation antipsychotics as add-on (Group I) or switch treatment (Group II) and its effect on QTc interval in a sample of schizophrenic and bipolar inpatients without medical illness. All patients had been evaluated twice by using ECG: on admission and after two weeks of hospitalization. Exclusions criteria were: abnormalities in levels of potassium, magnesium and calcium, cardiovascular and metabolic diseases, alcohol or drug abuse. We found a significant (p < 0.01) greater use of first generation antipsychotic in Group I (73.80%) than in the Group II (33.33%). Also Group I showed a significant increase (p < 0.0001) in total chlorpromazine equivalent (476. 78 ± 448.80 mg/day vs 845.48 ± 491.64 mg/day) and in QTc interval (369.14 ± 33.75 ms vs 387.09 ± 31.97 ms), while we did not find any statistical difference in Group II during hospitalization. Our results, in spite of the small sample size, indicate that antipsychotic add-on can increase QTc interval more than switching to other antipsychotic in psychiatric patients without other risk factors.