Optimal dose of neuroleptic in acute schizophrenia. A controlled study of the neuroleptic threshold and higher haloperidol dose. An exploratory haloperidol-controlled dose-finding study of ziprasidone in hospitalized patients with schizophrenia or schizoaffective disorder. Dosage of haloperidol for schizophrenia. Amisulpride, and atypical antipsychotic, in the treatment of acute episodes of schizophrenia: a dose-ranging study vs. haloperidol. The Amisulpride Study Group. Haloperidol for acute schizophrenic patients. An evaluation of three oral regimens. Plasma haloperidol levels and clinical effects in schizophrenia and schizoaffective disorder. Haloperidol: therapeutic window in schizophrenia. Pimozide versus Haloperidol in acute schizophrenia. A double blind controlled study. Parenteral haloperidol for rapid control of severe, disruptive symptoms of acute schizophrenia.
After individual determination of neuroleptic threshold (NT) doses of haloperidol, 106 patients with schizophrenia or schizoaffective disorder (Research Diagnostic Criteria) were treated openly at such doses (mean, 3.7 +/- 2.3 mg/d) for 2 weeks. Ten responding patients were discharged and unavailable for follow-up or refused subsequent randomization, and one non-responding patient refused randomization. The remaining 95 responding or nonresponding patients were then randomly assigned, double-blind, to a dosage of haloperidol two to 10 times higher (mean, 11.6 +/- 4.7 mg/d) or to a continuing NT dosage (mean, 3.4 +/- 2.3 mg/d) for another 2 weeks. Of the 58 patients exposed only to NT dosages of haloperidol, 72% clinically recovered within the 5-week trial. Higher dosages given to 47 patients did not lead to greater improvement in measures of psychosis, but did produce slightly greater declines in measures of hostility. Higher dosages did regularly lead to significant increases in distressing extrapyramidal side effects. Ninety patients with schizophrenia or schizoaffective disorder according to DSM-III-R criteria participated in this double-blind, exploratory, dose-ranging trial. After a single-blind washout period of 4 to 7 days, patients were randomly assigned to receive one of four fixed doses of the new antipsychotic, ziprasidone 4 (N = 19), 10 (N = 17), 40 (N = 17), or 160 (N = 20) mg/day or haloperidol 15 mg/day (N = 17) for 4 weeks. A dose-response relationship among ziprasidone groups was established for improvements in Clinical Global Impression Severity (CGI-S) score (p = 0.002) but not in Brief Psychiatric Rating Scale (BPRS) total score (p = 0.08). The intent-to-treat analysis of mean changes from baseline in the BPRS total, BPRS Psychosis core, and CGI-S scores demonstrated that ziprasidone 160 mg/day was comparable with haloperidol in reducing overall psychopathology and positive symptoms and was superior to ziprasidone 4 mg/day. Despite the small sample size and short duration of the trial, the improvement in CGI-S with both ziprasidone 160 mg/day and haloperidol 15 mg/day was statistically significantly greater than with ziprasidone 4 mg/day (p = 0.001 andp = 0.005, respectively). The percentage of patients classified as responders on both the BPRS total (> or = 30% improvement) and CGI-Improvement (score of 1 or 2) scales in the ziprasidone 160 mg/day group was similar to that in the haloperidol group and nonsignificantly greater than that in the ziprasidone 4 mg/day group. On all assessments of clinical efficacy, the improvements associated with ziprasidone 4 mg/day, 10 mg/day, and 40 mg/day were similar. Concomitant benztropine use at any time during the study was less frequent with ziprasidone 160 mg/day (15%) than with haloperidol (53%). Haloperidol was associated with a sustained hyperprolactinemia, unlike ziprasidone, where only transient elevations in prolactin that returned to normal within the dosing interval were observed. Ziprasidone was well tolerated, and the incidence of adverse events was similar in all groups. The results of this study suggest that ziprasidone 160 mg/day is as effective as haloperidol 15 mg/day in reducing overall psychopathology and positive symptoms of an acute exacerbation of schizophrenia or schizoaffective disorder but has a lower potential to induce extrapyramidal symptoms. Eighty-seven newly admitted inpatients with schizophrenia were randomized to receive 10, 30, or 80 mg/d of oral haloperidol. They were treated under double-blind conditions for 6 weeks, less if their acute symptoms remitted sooner. Survival analysis showed no differences among the three treatments. Side effects were minimal in all three treatment groups, and there were no differences in side effects among the groups. These results suggest that dosages higher than 10 mg/d of haloperidol for most patients have no additional beneficial effect in the treatment of acute or exacerbated schizophrenia. This 4-week, double-blind, randomized study was undertaken to determine the dose-response relationship of amisulpride in 319 patients with acute exacerbation of schizophrenia. Fixed doses of amisulpride (400, 800 and 1200 mg/day) and haloperidol (16 mg/day) were compared to amisulpride, 100 mg/day, as a potentially subtherapeutic dose. Efficacy data (BPRS total score and PANSS positive subscale) in the amisulpride groups generated a bell-shaped dose-response curve, with 400 mg/day and 800 mg/day being the most effective treatments for positive symptoms. Parkinsonism did not increase significantly between baseline and endpoint with amisulpride 400, 800 and 1200 mg/day compared to the amisulpride 100 mg/day group, whereas the difference was significant for haloperidol (P<0.05). It is concluded that amisulpride 400 mg and 800 mg/day is highly effective in treating the positive symptoms of schizophrenia, with less extrapyramidal side-effects than haloperidol 16 mg/day. The relative efficacy of three oral regimens of haloperidol was compared in a ten-day, double-blind study of 63 acutely ill schizophrenic patients newly admitted to the hospital. One group of patients received 20 mg of haloperidol on day 1, then increasing increments of 20 mg a day, reaching a maximum dosage of 100 mg daily on day 5. Another group received 10 mg of haloperidol on day 1, then increasing increments of 10 mg daily, reaching 100 mg daily on day 10. A third group of patients received a fixed dosage of 10 mg daily for ten days. Haloperidol was well tolerated by the patients; there were no serious adverse reactions. The data indicated that the regimens had similar therapeutic efficacy, suggesting that acutely ill schizophrenic patients respond to a wide range of doses of haloperidol but that onset of response and efficacy are not increased in most patients by providing a high initial loading dosage. Adequate, safe dosage must be determined in each case. Plasma haloperidol levels between 5 and 11 ng/mL may be clinically optimal for acutely exacerbated schizophrenia, but the evidence for this therapeutic window has been inconsistent.
                Haloperidol was administered in a double-blind manner during two consecutive 3-week experimental periods to 65 patients with acutely exacerbated schizophrenia or schizoaffective disorder. Two plasma levels were targeted: "low" (2 ng/mL) and "moderate" (10 ng/mL). The subjects were randomly assigned to four treatment sequences (low-low, low-moderate, moderate-moderate, or moderate-low).
                In the first 3 weeks, the antipsychotic efficacy of haloperidol increased with plasma levels up to approximately 12 ng/mL. In the second 3 weeks, decrease of plasma levels reduced negative symptoms.
                For most patients, plasma levels not exceeding 12 ng/mL yield the best results in the first 3 weeks of treatment. Subsequent lowering of the plasma levels may improve negative symptoms. Twenty-two schizophrenic inpatients were treated for 3 weeks with three randomly fixed oral doses of haloperidol (10, 20, or 30 mg). Analysis of the results by a nonlinear regression model revealed a curvilinear relationship between haloperidol levels in plasma and clinical response, as assessed on the Brief Psychiatric Rating Scale (pseudo-R2 = 0.85, F = 17.7, p < 0.001, correlation between coefficients ranged from 0.99 to -0.52). This curve defines roughly three drug level ranges (low, < 5.5 ng/ml; optimal, 5.5 to 14.4 ng/ml; and high or toxic, > 14.4 ng/ml), which are significant for clinical practice. Patients with high levels improve to a lesser extent or even worsen in negative symptoms, showing a nonstatistically significant trend to present more extrapyramidal symptoms. Our data thus support the existence of a therapeutic window for haloperidol. Schizophrenic patients with acute exacerbation and drug levels in this range would have a greater probability of global clinical improvement. Thirty acutely hospitalized schizophrenic patients were treated under double blind condition with either haloperidol (40-60 mg/day) or pimozide (40-60 mg/day) for 30 days. Ten patients in the pimozide and eleven in the haloperidol group showed a very good or good clinical response. There were no definite differences of treatment results as assessed by the Global Clinical Impression. Both groups showed a statistically significant decrease of the global scores of the Brief Psychiatric Rating Scale (p less than 0.01). There was a significant decrease of affective bluntedness and anergia in the pimozide but not in the haloperidol group. Extrapyramidal side effects were more pronounced in patients on pimozide who therefore needed more anticholinergic drugs. There was no consistent correlation between drug serum levels and global scores or single factors of the BPRS in either treatment group. It is concluded that pimozide in dose ranges from 40-60 mg has powerful antipsychotic properties indistinguishable from those of haloperidol but exerts stronger extrapyramidal side effects. Intramuscular haloperidol, at three dose levels, (5 mg, 2 mg, and 1 mg) chlorpromazine (25 mg), and placebo were compared for efficacy, rapidity of therapeutic onset, and safety in 50 acute psychotic patients requiring rapid control. The drugs were administered parenterally under double-blind conditions at half-hour intervals until successful control of moderate to very severe symptomatology was achieved or a maximum of four injections had been given. Global evaluation, BPRS, and target symptom ratings were performed. The overall results indicated that the 5 mg and 2 mg haloperidol doses were significantly superior to the 1 mg haloperidol and 25 mg chlorpromazine doses and to placebo. Transfer of patients to oral haloperidol was satisfactorily accomplished. Side effects for all medications were minimal and included slight to moderate EPS and drowsiness. The use of antiparkinson drugs completely controlled the extrapyramidal symptoms.
No results are conclusive and all are based on small, short, studies. It would be understandable, however, if clinicians were cautious in prescribing doses in excess of 7.5 mg/day of haloperidol to a person with uncomplicated acute schizophrenia, and if people with schizophrenia were equally reticent to take greater doses. Further research is needed regarding the efficacy and tolerability of the >1.5-3.0 mg/day dose range.