A post hoc analysis of transitioning to oral treatment with olanzapine or haloperidol after 24-hour intramuscular treatment in acutely agitated adult patients with schizophrenia

Haloperidol (oral) versus olanzapine (oral) for people with schizophrenia and schizophrenia-spectrum disorders

BACKGROUND

Schizophrenia is often a severe and disabling psychiatric disorder. Antipsychotics remain the mainstay of psychotropic treatment for people with psychosis. In limited resource and humanitarian contexts, it is key to have several options for beneficial, low-cost antipsychotics, which require minimal monitoring. We wanted to compare oral haloperidol, as one of the most available antipsychotics in these settings, with a second-generation antipsychotic, olanzapine.

OBJECTIVES

To assess the clinical benefits and harms of haloperidol compared to olanzapine for people with schizophrenia and schizophrenia-spectrum disorders.

SEARCH METHODS

We searched the Cochrane Schizophrenia study-based register of trials, which is based on monthly searches of CENTRAL, CINAHL, ClinicalTrials.gov, Embase, ISRCTN, MEDLINE, PsycINFO, PubMed and WHO ICTRP. We screened the references of all included studies. We contacted relevant authors of trials for additional information where clarification was required or where data were incomplete. The register was last searched on 14 January 2023.

SELECTION CRITERIA

Randomised clinical trials comparing haloperidol with olanzapine for people with schizophrenia and schizophrenia-spectrum disorders. Our main outcomes of interest were clinically important change in global state, relapse, clinically important change in mental state, extrapyramidal side effects, weight increase, clinically important change in quality of life and leaving the study early due to adverse effects.

DATA COLLECTION AND ANALYSIS

We independently evaluated and extracted data. For dichotomous outcomes, we calculated risk ratios (RR) and their 95% confidence intervals (CI) and the number needed to treat for an additional beneficial or harmful outcome (NNTB or NNTH) with 95% CI. For continuous data, we estimated mean differences (MD) or standardised mean differences (SMD) with 95% CIs. For all included studies, we assessed risk of bias (RoB 1) and we used the GRADE approach to create a summary of findings table.

MAIN RESULTS

We included 68 studies randomising 9132 participants. We are very uncertain whether there is a difference between haloperidol and olanzapine in clinically important change in global state (RR 0.84, 95% CI 0.69 to 1.02; 6 studies, 3078 participants; very low-certainty evidence). We are very uncertain whether there is a difference between haloperidol and olanzapine in relapse (RR 1.42, 95% CI 1.00 to 2.02; 7 studies, 1499 participants; very low-certainty evidence). Haloperidol may reduce the incidence of clinically important change in overall mental state compared to olanzapine (RR 0.70, 95% CI 0.60 to 0.81; 13 studies, 1210 participants; low-certainty evidence). For every eight people treated with haloperidol instead of olanzapine, one fewer person would experience this improvement. The evidence suggests that haloperidol may result in a large increase in extrapyramidal side effects compared to olanzapine (RR 3.38, 95% CI 2.28 to 5.02; 14 studies, 3290 participants; low-certainty evidence). For every three people treated with haloperidol instead of olanzapine, one additional person would experience extrapyramidal side effects. For weight gain, the evidence suggests that there may be a large reduction in the risk with haloperidol compared to olanzapine (RR 0.47, 95% CI 0.35 to 0.61; 18 studies, 4302 participants; low-certainty evidence). For every 10 people treated with haloperidol instead of olanzapine, one fewer person would experience weight increase. A single study suggests that haloperidol may reduce the incidence of clinically important change in quality of life compared to olanzapine (RR 0.72, 95% CI 0.57 to 0.91; 828 participants; low-certainty evidence). For every nine people treated with haloperidol instead of olanzapine, one fewer person would experience clinically important improvement in quality of life. Haloperidol may result in an increase in the incidence of leaving the study early due to adverse effects compared to olanzapine (RR 1.99, 95% CI 1.60 to 2.47; 21 studies, 5047 participants; low-certainty evidence). For every 22 people treated with haloperidol instead of olanzapine, one fewer person would experience this outcome. Thirty otherwise relevant studies and several endpoints from 14 included studies could not be evaluated due to inconsistencies and poor transparency of several parameters. Furthermore, even within studies that were included, it was often not possible to use data for the same reasons. Risk of bias differed substantially for different outcomes and the certainty of the evidence ranged from very low to low. The most common risks of bias leading to downgrading of the evidence were blinding (performance bias) and selective reporting (reporting bias).

AUTHORS' CONCLUSIONS

Overall, the certainty of the evidence was low to very low for the main outcomes in this review, making it difficult to draw reliable conclusions. We are very uncertain whether there is a difference between haloperidol and olanzapine in terms of clinically important global state and relapse. Olanzapine may result in a slightly greater overall clinically important change in mental state and in a clinically important change in quality of life. Different side effect profiles were noted: haloperidol may result in a large increase in extrapyramidal side effects and olanzapine in a large increase in weight gain. The drug of choice needs to take into account side effect profiles and the preferences of the individual. These findings and the recent inclusion of olanzapine alongside haloperidol in the WHO Model List of Essential Medicines should increase the likelihood of it becoming more easily available in low- and middle- income countries, thereby improving choice and providing a greater ability to respond to side effects for people with lived experience of schizophrenia. There is a need for additional research using appropriate and equivalent dosages of these drugs. Some of this research needs to be done in low- and middle-income settings and should actively seek to account for factors relevant to these. Research on antipsychotics needs to be person-centred and prioritise factors that are of interest to people with lived experience of schizophrenia.

Haloperidol for psychosis-induced aggression or agitation (rapid tranquillisation)

BACKGROUND

Haloperidol used alone is recommended to help calm situations of aggression or agitation for people with psychosis. It is widely accessible and may be the only antipsychotic medication available in limited-resource areas.

OBJECTIVES

To examine whether haloperidol alone is an effective treatment for psychosis-induced aggression or agitation, wherein clinicians are required to intervene to prevent harm to self and others.

SEARCH METHODS

We searched the Cochrane Schizophrenia Group's Study-Based Register of Trials (26th May 2016). This register is compiled by systematic searches of major resources (including AMED, BIOSIS CINAHL, Embase, MEDLINE, PsycINFO, PubMed, and registries of clinical trials) and their monthly updates, handsearches, grey literature, and conference proceedings, with no language, date, document type, or publication status limitations for inclusion of records into the register.

SELECTION CRITERIA

Randomised controlled trials (RCTs) involving people exhibiting aggression and/or agitation thought to be due to psychosis, allocated rapid use of haloperidol alone (by any route), compared with any other treatment. Outcomes of interest included tranquillisation or asleep by 30 minutes, repeated need for rapid tranquillisation within 24 hours, specific behaviours (threat or injury to others/self), adverse effects. We included trials meeting our selection criteria and providing useable data.

DATA COLLECTION AND ANALYSIS

We independently inspected all citations from searches, identified relevant abstracts, and independently extracted data from all included studies. For binary data we calculated risk ratio (RR), for continuous data we calculated mean difference (MD), and for cognitive outcomes we derived standardised mean difference (SMD) effect sizes, all with 95% confidence intervals (CI) and using a fixed-effect model. We assessed risk of bias for the included studies and used the GRADE approach to produce 'Summary of findings' tables which included our pre-specified main outcomes of interest.

MAIN RESULTS

We found nine new RCTs from the 2016 update search, giving a total of 41 included studies and 24 comparisons. Few studies were undertaken in circumstances that reflect real-world practice, and, with notable exceptions, most were small and carried considerable risk of bias. Due to the large number of comparisons, we can only present a summary of main results.Compared with placebo, more people in the haloperidol group were asleep at two hours (2 RCTs, n=220, RR 0.88, 95%CI 0.82 to 0.95, very low-quality evidence) and experienced dystonia (2 RCTs, n=207, RR 7.49, 95%CI 0.93 to 60.21, very low-quality evidence).Compared with aripiprazole, people in the haloperidol group required fewer injections than those in the aripiprazole group (2 RCTs, n=473, RR 0.78, 95%CI 0.62 to 0.99, low-quality evidence). More people in the haloperidol group experienced dystonia (2 RCTs, n=477, RR 6.63, 95%CI 1.52 to 28.86, very low-quality evidence).Four trials (n=207) compared haloperidol with lorazepam with no significant differences with regard to number of participants asleep at one hour (1 RCT, n=60, RR 1.05, 95%CI 0.76 to 1.44, very low-quality of evidence) or those requiring additional injections (1 RCT, n=66, RR 1.14, 95%CI 0.91 to 1.43, very low-quality of evidence).Haloperidol's adverse effects were not offset by addition of lorazepam (e.g. dystonia 1 RCT, n=67, RR 8.25, 95%CI 0.46 to 147.45, very low-quality of evidence).Addition of promethazine was investigated in two trials (n=376). More people in the haloperidol group were not tranquil or asleep by 20 minutes (1 RCT, n=316, RR 1.60, 95%CI 1.18 to 2.16, moderate-quality evidence). Acute dystonia was too common in the haloperidol alone group for the trial to continue beyond the interim analysis (1 RCT, n=316, RR 19.48, 95%CI 1.14 to 331.92, low-quality evidence).

AUTHORS' CONCLUSIONS

Additional data from new studies does not alter previous conclusions of this review. If no other alternative exists, sole use of intramuscular haloperidol could be life-saving. Where additional drugs are available, sole use of haloperidol for extreme emergency could be considered unethical. Addition of the sedating promethazine has support from better-grade evidence from within randomised trials. Use of an alternative antipsychotic drug is only partially supported by fragmented and poor-grade evidence. Adding a benzodiazepine to haloperidol does not have strong evidence of benefit and carries risk of additional harm.After six decades of use for emergency rapid tranquillisation, this is still an area in need of good independent trials relevant to real-world practice.

Haloperidol versus placebo for schizophrenia

BACKGROUND

Haloperidol was developed in the late 1950s for use in the field of anaesthesia. Research subsequently demonstrated effects on hallucinations, delusions, aggressiveness, impulsiveness and states of excitement and led to the introduction of haloperidol as an antipsychotic.

OBJECTIVES

To evaluate the clinical effects of haloperidol for the management of schizophrenia and other similar serious mental illnesses compared with placebo.

SEARCH METHODS

Initially, we electronically searched the databases of Biological Abstracts (1985-1998), CINAHL (1982-1998), The Cochrane Library (1998, Issue 4), The Cochrane Schizophrenia Group's Register (December 1998), EMBASE (1980-1998), MEDLINE (1966-1998), PsycLIT (1974-1998), and SCISEARCH. We also checked references of all identified studies for further trial citations and contacted the authors of trials and pharmaceutical companies for further information and archive material.For the 2012 update, on 15 May 2012, we searched the Cochrane Schizophrenia Group's Trials Register.

SELECTION CRITERIA

We included all relevant randomised controlled trials comparing the use of haloperidol (any oral dose) with placebo for those with schizophrenia or other similar serious, non-affective psychotic illnesses (however diagnosed). Our main outcomes of interest were death, loss to follow-up, clinical and social response, relapse and severity of adverse effects.

DATA COLLECTION AND ANALYSIS

We evaluated data independently and extracted, re-inspected and quality assessed the data. We analysed dichotomous data using risk ratio (RR) and calculated their 95% confidence intervals (CI). For continuous data, we calculated mean differences (MD). We excluded continuous data if loss to follow-up was greater than 50% and inspected data for heterogeneity. We used a fixed-effect model for all analyses. For the 2012 update, we assessed risk of bias of included studies and used the GRADE approach to create a 'Summary of findings' table.

MAIN RESULTS

Twenty-five trials randomising 4651 people are now included in this review. We chose seven main outcomes of interest for the 'Summary of findings' table. More people allocated haloperidol improved in the first six weeks of treatment than those given placebo (4 RCTs n = 472, RR 0.67 CI 0.56 to 0.80, moderate quality evidence). A further eight trials also found a difference favouring haloperidol across the six weeks to six months period (8 RCTs n = 307 RR 0.67 CI 0.58 to 0.78, moderate quality evidence). Relapse data from two trials favoured haloperidol at < 52 weeks but the evidence was very low quality (2 RCTs n = 70, RR 0.69 CI 0.55 to 0.86). Moderate quality evidence showed about half of those entering studies failed to complete the short trials (six weeks to six months), although, at up to six weeks, 16 studies found a difference that marginally favoured haloperidol (n = 1812, RR 0.87 CI 0.80 to 0.95). Adverse effect data does, nevertheless, support clinical impression that haloperidol is a potent cause of movement disorders, at least in the short term. Moderate quality evidence indicates that haloperidol caused parkinsonism (5 RCTs n = 485, RR 5.48 CI 2.68 to 11.22), akathisia (6 RCTs n = 695, RR 3.66 CI 2.24 to 5.97, and acute dystonia (5 RCTs n = 471, RR 11.49 CI 3.23 to 10.85). Discharge from hospital was equivocal between groups (1 RCT n = 33, RR 0.85 CI 0.47 to 1.52, very low quality evidence). Data were not reported for death and patient satisfaction.

AUTHORS' CONCLUSIONS

Haloperidol is a potent antipsychotic drug but has a high propensity to cause adverse effects. Where there is no treatment option, use of haloperidol to counter the damaging and potentially dangerous consequences of untreated schizophrenia is justified. However, where a choice of drug is available, people with schizophrenia and clinicians may wish to prescribe an alternative antipsychotic with less likelihood of adverse effects such as parkinsonism, akathisia and acute dystonias. Haloperidol should be less favoured as a control drug for randomised trials of new antipsychotics.

Haloperidol for psychosis-induced aggression or agitation (rapid tranquillisation)

BACKGROUND

Haloperidol, used alone is recommended to help calm situations of aggression with people with psychosis. This drug is widely accessible and may be the only antipsychotic medication available in areas where resources are limited.

OBJECTIVES

To investigate whether haloperidol alone, administered orally, intramuscularly or intravenously, is effective treatment for psychosis-induced agitation or aggression.

SEARCH METHODS

We searched the Cochrane Schizophrenia Group Trials Register (1st June 2011).

SELECTION CRITERIA

Randomised controlled  trials (RCTs) involving people exhibiting agitation or aggression (or both) thought to be due to psychosis, allocated rapid use of haloperidol alone (by any route), compared with any other treatment. Outcomes included tranquillisation or asleep by 30 minutes, repeated need for rapid tranquillisation within 24 hours, specific behaviours (threat or injury to others/self), adverse effects.

DATA COLLECTION AND ANALYSIS

We independently selected and assessed studies for methodological quality and extracted data. 'Summary of findings' tables were produced for each comparison grading the evidence and calculating, where possible and appropriate, a range of absolute effects.

MAIN RESULTS

We included 32 studies comparing haloperidol with 18 other treatments. Few studies were undertaken in circumstances that reflect real world practice, and, with notable exceptions, most were small and carried considerable risk of bias.Compared with placebo, more people in the haloperidol group were asleep at two hours (2 RCTs, n = 220, risk ratio (RR) 0.88, 95% confidence interval (CI) 0.82 to 0.95). Dystonia was common (2 RCTs, n = 207, RR 7.49, CI 0.93 to 60.21). Compared with aripiprazole, people in the haloperidol group required fewer injections than those in the aripiprazole group (2 RCTs, n = 473, RR 0.78, CI 0.62 to 0.99). More people in the haloperidol group experienced dystonia (2 RCTs, n = 477, RR 6.63, CI 1.52 to 28.86).Despite three larger trials with ziprasidone (total n = 739), data remain patchy, largely because of poor design and reporting. Compared with zuclopenthixol acetate, more people who received haloperidol required more than three injections (1 RCT, n = 70, RR 2.54, CI 1.19 to 5.46).Three trials (n = 205) compared haloperidol with lorazepam. There were no significant differences between the groups with regard to the number of participants asleep at one hour (1 RCT, n = 60, RR 1.05, CI 0.76 to 1.44). However, by three hours, significantly more people were asleep in the lorazepam group compared with the haloperidol group (1 RCT, n = 66, RR 1.93, CI 1.14 to 3.27). There were no differences in numbers requiring more than one injection (1 RCT, n = 66, RR 1.14, CI 0.91 to 1.43).Haloperidol's adverse effects were not offset by addition of lorazepam (e.g. dystonia 1 RCT, n = 67, RR 8.25, CI 0.46 to 147.45; required antiparkinson medication RR 2.74, CI 0.81 to 9.25). Addition of promethazine was investigated in one larger and better graded trial (n = 316). More people in the haloperidol group were not tranquil or asleep by 20 minutes (RR 1.60, CI 1.18 to 2.16). Significantly more people in the haloperidol alone group experienced one or more adverse effects (RR 11.28, CI 1.47 to 86.35). Acute dystonia for those allocated haloperidol alone was too common for the trial to continue beyond the interim analysis (RR 19.48, CI 1.14 to 331.92).

AUTHORS' CONCLUSIONS

If no other alternative exists, sole use of intramuscular haloperidol could be life-saving. Where additional drugs to offset the adverse effects are available, sole use of haloperidol for the extreme emergency, in situations of coercion, could be considered unethical. Addition of the sedating promethazine has support from better-grade evidence from within randomised trials. Use of an alternative antipsychotic drug is only partially supported by fragmented and poor-grade evidence. Evidence for use of newer generation antipsychotic alternatives is no stronger than that for older drugs. Adding a benzodiazepine to haloperidol does not have strong evidence of benefit and carries a risk of additional harm.After six decades of use for emergency rapid tranquillisation, this is still an area in need of good independent trials relevant to real world practice.

A meta-analysis of the risk of acute extrapyramidal symptoms with intramuscular antipsychotics for the treatment of agitation

OBJECTIVE

We examined the evidence for a decreased risk of extrapyramidal symptoms (EPS) with intramuscular second-generation antipsychotics (SGAs) versus intramuscular haloperidol alone or in combination with an anticholinergic agent.

DATA SOURCES

We searched MEDLINE (1950 to the present), and EMBASE and the Cochrane Database through January 16, 2008, for studies published in English of intramuscular SGAs and intramuscular haloperidol alone or in combination with an anticholinergic agent using the following drug names: ziprasidone, Geodon, olanzapine, Zyprexa, aripiprazole, Abilify, haloperidol, and Haldol. We then searched this pool of studies for trials with the terms intramuscular, IM, or injectable. Initially, we included only randomized controlled trials (RCTs). To obtain more data comparing SGAs to the combination of haloperidol and an anticholinergic, we conducted a second analysis including studies of any methodology.

STUDY SELECTION

Seven RCTs that compared intramuscular SGAs to intramuscular haloperidol alone were identified. However, we found only one RCT of haloperidol plus an anticholinergic. In the second analysis, we identified 18 studies, including 4 using haloperidol combined with promethazine (an antihistamine with anticholinergic properties).

DATA EXTRACTION

The primary outcome measure was acute dystonia; secondary outcome measures included akathisia, parkinsonism, or the need for additional anticholinergic medication. For RCTs, risk ratios (RRs) and 95% confidence intervals (CIs) were calculated for each outcome. When all studies were included in the second analysis, we calculated the risk of acute dystonia.

DATA SYNTHESIS

Among RCTs (N = 2032), SGAs were associated with a significantly lower risk of acute dystonia (RR = 0.19, 95% CI = 0.10 to 0.39), akathisia (RR = 0.25, 95% CI = 0.14 to 0.44), and anticholinergic use (RR = 0.19, 95% CI = 0.09 to 0.43) compared with haloperidol alone. When all trials were considered (N = 3425), rates of acute dystonia were higher for haloperidol alone (4.7%) than for SGAs (0.6%) or for haloperidol plus promethazine (0.0%).

CONCLUSIONS

Intramuscular SGAs have a significantly lower risk of acute EPS compared to haloperidol alone. However, intramuscular haloperidol plus promethazine has a risk of acute dystonia comparable to intramuscular SGAs. The decision to use SGAs should consider other factors in addition to the reduction of EPS, which can be prevented by the use of an anticholinergic agent.

Haloperidol versus placebo for schizophrenia

BACKGROUND

Haloperidol was developed in the late 1950s for use in the field of anaesthesia. Research subsequently demonstrated effects on hallucinations, delusions, aggressiveness, impulsiveness and states of excitement and led to the introduction of haloperidol as an antipsychotic.

OBJECTIVES

To evaluate the clinical effects of haloperidol for the management of schizophrenia and other similar serious mental illnesses compared to placebo.

SEARCH STRATEGY

We initially electronically searched the databases of Biological Abstracts (1985-1998), CINAHL (1982-1998), The Cochrane Library (1998, Issue 4), The Cochrane Schizophrenia Group's Register (December 1998), EMBASE (1980-1998), MEDLINE (1966-1998), PsycLIT (1974-1998), and SCISEARCH. We also checked references of all identified studies for further trial citations and contacted the authors of trials and pharmaceutical companies for further information and archive material. For the 2005 update we searched The Cochrane Library (2005, Issue 6).

SELECTION CRITERIA

We included all relevant randomised controlled trials comparing the use of haloperidol (any oral dose) with placebo for those with schizophrenia or other similar serious, non-affective psychotic illnesses (however diagnosed). Our main outcomes of interest were death, loss to follow up, clinical and social response, relapse and severity of adverse effects.

DATA COLLECTION AND ANALYSIS

We evaluated data independently and analysed on an intention-to-treat basis, assuming that people who left the study early, or were lost to follow-up, had no improvement. Where possible and appropriate, we analysed dichotomous data using Relative Risk (RR) and calculated their 95% confidence intervals (CI). If appropriate, the number needed to treat (NNT) or number needed to harm (NNH) was estimated. For continuous data, we calculated weighted mean differences. We excluded continuous data if loss to follow up was greater than 50% and inspected data for heterogeneity.

MAIN RESULTS

Twenty-one trials randomising 1519 people are now included in this review. One new trial, Kane 2002 (n=414) has been added but it did not affect the overall results. More people allocated haloperidol improved in the first six weeks of treatment than those given placebo (3RCTs n=159, RR failing to produce a marked improvement 0.44 CI 0.3 to 0.6, NNT 3 CI 2 to 5). A further eight trials also found a difference favouring haloperidol across the 6-24 week period (8 RCTs n=308 RR no marked global improvement 0.68 CI 0.6 to 0.8 NNT 3 CI 2.5 to 5) but this may be an over estimate of effect as small negative studies were not identified. About half of those entering studies failed to complete the short trials, although, at 0-6 weeks, 11 studies found a difference that marginally favoured haloperidol (11 RCTs n=898, RR 0.8 CI 0.7 to 0.9, NNT 59 CI 38 to 200). Adverse effect data does, nevertheless, support clinical impression, that haloperidol is a potent cause of movement disorders, at least in the short term. Haloperidol promotes acute dystonia (3 RCTs n=93, RR 4.7 CI 1.7 to 44, NNH 5 CI 3 to 9), akathisia (4 RCTs n=333, RR 2.6 CI 1.4 to 4.8, NNH 7 CI 3 to 25) and parkinsonism (4 RCTs n=163, RR 11.7 CI 2.9 to 47, NNH 3 CI 2 to 5).

AUTHORS' CONCLUSIONS

Haloperidol is a potent antipsychotic drug but has a high propensity to cause adverse effects. Where there is no treatment option, use of haloperidol to counter the damaging and potentially dangerous consequences of untreated schizophrenia is justified. However, where a choice of drug is available, people with schizophrenia and clinicians may wish to prescribe an alternative antipsychotic with less likelihood of adverse effects such as parkinsonism, akathisia and acute dystonias. Haloperidol should not be a control drug of choice for randomised trials of new antipsychotics.