Antipsychotics (also known as neuroleptics or major tranquilizers) are a class of psychiatric medication primarily used to manage psychosis (including delusions, hallucinations, or disordered thought), in particular in schizophrenia and bipolar disorder, and are increasingly being used in the management of non-psychotic disorders (ATC code N05A). The word neuroleptic originates from the Greek word lepsis ("seizure" or "fit").
First-generation antipsychotics, known as typical antipsychotics, were discovered in the 1950s. Most second-generation drugs, known as atypical antipsychotics, have been developed more recently, although the first atypical antipsychotic, clozapine, was discovered in the 1950s and introduced clinically in the 1970s. Both generations of medication tend to block receptors in the brain's dopamine pathways, but atypicals tend to act on serotonin receptors as well.
Notable and relatively common adverse effects of antipsychotics include extrapyramidal symptoms (which involve motor control) and hyperprolactinaemia primarily in typicals and weight gain and metabolic abnormalities mostly in atypicals.
Antipsychotics are used to treat certain mental disorders according to the indications of a given antipsychotic. In all cases, antipsychotics should only be prescribed after a physician has conducted an initial evaluation and made a plan for appropriate ongoing monitoring. The physician's initial evaluation which precedes a recommendation for using antipsychotics includes physical examination, psychological evaluation, and assessment of any social or environmental concerns. Monitoring includes planning re-evaluation and documentation of dose, efficacy and adverse effects at regular intervals. This is done by conducting tests which would detect movement disorder and neurological symptoms, as well as changes in weight or body mass index, blood pressure; heart rate; blood sugar, and lipid profile.
Antipsychotics are prescribed one at a time. In cases in which single antipsychotics are tried alone, and when one of those three cases was Clozapine if possible, then two antipsychotics may be prescribed at the same time. In that case, the physician should have a monitoring plan which includes an attempt to deprescribe and only use one antipsychotic.
Antipsychotics are most frequently used for the following conditions:
They are not recommended for dementia or insomnia unless other treatments have not worked. They are not recommended in children unless other treatments are not effective or unless the child has psychosis. Two different antipsychotics should not typically be used in the same person.
Treatment guidelines from the British Association for Psychopharmacology and the American Psychiatric Association recommend antipsychotic drugs as a first line treatment for patients with schizophrenia. The National Institute of Health and Care Excellence (NICE) recommends antipsychotic medication in combination with psychosocial therapy, and further recommends that patients expressing a preference for psychosocial therapy alone be informed that better treatment outcomes are achieved in combination with antipsychotic medication.
Placebo-controlled clinical trials have consistently shown superiority for active treatment with an antipsychotic drug compared to treatment with placebo. The efficacy of such drugs is suboptimal. Few patients achieve complete resolution of symptoms. Response rates, calculated using various cutoff values for symptom reduction, are low and their interpretation is complicated by high placebo response rates and selective publication of clinical trial results. In longer trials, maintenance treatment with antipsychotic drugs has been shown to be superior to placebo in reducing relapse.
A review of schizophrenia clinical trial methodology, despite stating that the overall quality is "rather good," reported issues with the selection of participants (including that, in schizophrenia trials, in general up to 90% of people that are suitable do not meet the elaborate inclusion and exclusion criteria, and that negative symptoms have not been properly assessed despite companies marketing the newer antipsychotics for these); issues with the design of trials (including pharmaceutical company funding of most of them, and inadequate experimental "blinding" so that trial participants could sometimes tell whether they were on placebo or not); and issues with the assessment of outcomes (including the use of a minimal reduction in scores to show "response," lack of assessment of quality of life or recovery, a high rate of discontinuation, selective highlighting of favorable results in the abstracts of publications, and poor reporting of side-effects).
Antipsychotics are routinely used, often in conjunction with mood stabilisers such as lithium/valproate, as a first-line treatment for manic and mixed episodes associated with bipolar disorder. The reason for this combination is the therapeutic delay of the aforementioned mood stabilisers (for valproate therapeutic effects are usually seen around five days after treatment is commenced whereas lithium usually takes at least a week before the full therapeutic effects are seen) and the comparatively rapid antimanic effects of antipsychotic drugs. The antipsychotics have a documented efficacy when used alone in acute mania/mixed episodes.
Three atypical antipsychotics (lurasidone, olanzapine and quetiapine) have also been found to possess efficacy in the treatment of bipolar depression as a monotherapy. Whereas only olanzapine and quetiapine have been proven to be effective broad-spectrum (i.e. against all three types of relapse— manic, mixed and depressive) prophylactic (or maintenance) treatments in patients with bipolar disorder. A recent Cochrane review also found that olanzapine had a less favourable risk/benefit ratio than lithium as a maintenance treatment for bipolar disorder.
The American Psychiatric Association and the UK National Institute for Health and Care Excellence recommend antipsychotics for managing acute psychotic episodes in schizophrenia or bipolar disorder, and as a longer-term maintenance treatment for reducing the likelihood of further episodes. They state that response to any given antipsychotic can be variable so that trials may be necessary, and that lower doses are to be preferred where possible. A number of studies have looked at levels of "compliance" or "adherence" with antipsychotic regimes and found that discontinuation (stopping taking them) by patients is associated with higher rates of relapse, including hospitalization.
Antipsychotics in old age dementia showed a modest benefit compared to placebo in managing aggression or psychosis, but this is combined with a significant increase in serious adverse events. Thus, antipsychotics should not be used routinely to treat dementia with aggression or psychosis, but may be an option in a few cases where there is severe distress or risk of physical harm to others. Psychosocial interventions may reduce the need for antipsychotics.
A number of second-generation (or atypical) antipsychotics have proven to be effective adjuncts in the treatment of major depressive disorder of which aripiprazole, quetiapine, and olanzapine (when used in conjunction with fluoxetine) have received FDA labelling for this indication. Quetiapine has also proven effective as a monotherapy in major depressive disorder.
Besides the above uses antipsychotics may be used for Obsessive-compulsive disorder, Posttraumatic stress disorder, personality disorders, Tourette syndrome, autism (for which both aripiprazole and risperidone are FDA-labelled) and agitation in those with dementia. Evidence however does not support the use of atypical antipsychotics in eating disorders or personality disorder. Risperidone may be useful for obsessive compulsive disorder. The use of low doses of antipsychotics for insomnia, while common, is not recommended as there is little evidence of benefit and concerns regarding adverse effects. Low dose antipsychotics may also be used in treatment of impulse-behavioural and cognitive-perceptual symptoms of borderline personality disorder.
In children they may be used in those with disruptive behavior disorders, mood disorders and pervasive developmental disorders or intellectual disability. Antipsychotics are only weakly recommended for Tourette syndrome as well they are effective side effects are common. The situation is similar in autism spectrum disorder. Much of the evidence for the off-label use of antipsychotics (for example, for dementia, OCD, PTSD, Personality Disorders, Tourette's) was of insufficient scientific quality to support such use, especially as there was strong evidence of increased risks of stroke, tremors, significant weight gain, sedation, and gastrointestinal problems. A UK review of unlicensed usage in children and adolescents reported a similar mixture of findings and concerns. A survey of children with pervasive developmental disorder found that 16.5% were taking an antipsychotic drug, most commonly for irritability, aggression, and agitation. Recently, risperidone was approved by the US FDA for the treatment of irritability in children and adolescents with autism.
Aggressive challenging behavior in adults with intellectual disability is often treated with antipsychotic drugs despite lack of an evidence base. A recent randomized controlled trial, however, found no benefit over placebo and recommended that the use of antipsychotics in this way should no longer be regarded as an acceptable routine treatment.
While the atypical (second-generation) antipsychotics were marketed as offering greater efficacy and reduced side effects than typical medications this may not be true. One review concluded there were no differences while another found that atypicals were "only moderately more efficacious". These conclusions were, however, questioned by another review, which found that clozapine, amisulpride, and olanzapine and risperidone were more effective Clozapine has appeared to be more effective than other atypical antipsychotics, although it requires close monitoring of patients due to its association with potentially fatal angranulocytosis. Due to bias in the research the accuracy of comparisons of atypical antipsychotics is a concern.
In 2005, the US government body National Institute of Mental Health published the results of a major independent (not funded by the pharmaceutical companies) multi-site, double-blind study (the CATIE project). This study compared several atypical antipsychotics to an older typical antipsychotic, perphenazine, among 1493 persons with schizophrenia. The study found that only olanzapine outperformed perphenazine in discontinuation rate (the rate at which people stopped taking it due to its effects). The authors noted an apparent superior efficacy of olanzapine to the other drugs in terms of reduction in psychopathology and rate of hospitalizations, but olanzapine was associated with relatively severe metabolic effects such as a major weight gain problem (averaging 9.4 lbs) and increases in glucose, cholesterol, and triglycerides. The mean and maximal doses used for olanzapine were considerably higher than standard practice, and this has been postulated as a biasing factor that may explain olanzapine's superior efficacy over the other atypical antipsychotics studied, where doses were more in line with clinically relevant practices. No other atypical studied (risperidone, quetiapine, and ziprasidone) did better than the typical perphenazine on the measures used, nor did they produce fewer adverse effects than the typical antipsychotic perphenazine, although more patients discontinued perphenazine owing to extrapyramidal effects compared to the atypical agents (8% vs. 2% to 4%).
Compliance has not been shown to be different between the two types.
Many researchers question the first-line prescribing of atypicals over typicals, and some even question the distinction between the two classes. In contrast, other researchers point to the significantly higher risk of tardive dyskinesia and extrapyramidal symptoms with the typicals and for this reason alone recommend first-line treatment with the atypicals, notwithstanding a greater propensity for metabolic adverse effects in the latter. The UK government organization NICE recently revised its recommendation favoring atypicals, to advise that the choice should be an individual one based on the particular profiles of the individual drug and on the patient's preferences.
The re-evaluation of the evidence has not necessarily slowed the bias toward prescribing the atypicals.
Antipsychotics are associated with a range of side effects. It is well-recognized that many people stop taking them (around two-thirds even in controlled drug trials) due in part to adverse effects.
More than one antipsychotic drug should not be used at a time except under unusual circumstances. Among the reasons for this are the increased number and harm from adverse effects of the drug when multiple drugs are used.
Some studies have found decreased life expectancy associated with the use of antipsychotics, and argued that more studies are needed. Antipsychotics may also increase the risk of early death in individuals with dementia. In individuals without psychosis, doses of antipsychotics can produce the "negative symptoms" of schizophrenia such as amotivation. Antipsychotics typically worsen symptoms in people who suffer from depersonalisation disorder. Antipsychotic polypharmacy (prescribing two or more antipsychotics at the same time for an individual) is a common practice but not evidence-based or recommended, and there are initiatives to curtail it. Similarly, the use of excessively high doses (often the result of polypharmacy) continues despite clinical guidelines and evidence indicating that it is usually no more effective but is usually more harmful.
Loss of grey matter and other brain structural changes over time are observed in schizophrenia. Meta analyses of the effects of antipsychotic treatment on the course of grey matter loss and structural changes have reached conflicting conclusions. A 2012 meta analysis concluded that grey matter loss is greater in patients treated with first generation antipsychotics relative to those treated with atypicals, and hypothesized a protective effect of atypicals as one possible explanation. A second meta analyses suggested that treatment with antipsychotics was associated with increased grey matter loss.
Subtle, long-lasting forms of akathisia are often overlooked or confused with post-psychotic depression, in particular when they lack the extra pyramidal aspect that psychiatrists have been taught to expect when looking for signs of akathisia. Part of the reason for underdiagnosis is the erroneous belief that second-generation antipsychotics rarely cause akathisia.
Withdrawal symptoms from antipsychotics may emerge during dosage reduction and discontinuation. Withdrawal symptoms can include nausea, emesis, anorexia, diarrhea, rhinorrhea, diaphoresis, myalgia, paresthesia, anxiety, agitation, restlessness, and insomnia. The psychological withdrawal symptoms can include psychosis, and can be mistaken for a relapse of the underlying disorder. Conversely, the withdrawal syndrome may also be a trigger for relapse. Better management of the withdrawal syndrome may improve the ability of individuals to discontinue antipsychotics.
Tardive dyskinesia may abate during withdrawal from the antispsychotic agent, or it may persist.
Withdrawal effects may also occur when switching a person from one antipsychotic to another, (it is presumed due to variations of potency and receptor activity). Such withdrawal effects can include cholinergic rebound, an activation syndrome, and motor syndromes including dyskinesias. These adverse effects are more likely during rapid changes between antipsychotic agents, so making a gradual change between antipsychotics minimises these withdrawal effects. The British National Formulary recommends a gradual withdrawal when discontinuing antipsychotic treatment to avoid acute withdrawal syndrome or rapid relapse. The process of cross-titration involves gradually increasing the dose of the new medication while gradually decreasing the dose of the old medication.
Clinically used antipsychotic medications are listed below by drug group. Trade names appear in parentheses.
† indicates drugs that are no longer marketed in English-speaking countries.
‡ denotes drugs that are no longer (or were never to begin with) marketed in the US. Some antipsychotics are not firmly placed in either first-generation or second-generation classes.
# denotes drugs that have been withdrawn worldwide.
This category is for drugs that have been called both first and second-generation, depending on the literature being used.
* where ‡‡ indicates drugs for which development has ceased
All antipsychotic drugs tend to block D2 receptors in the dopamine pathways of the brain. This means that dopamine released in these pathways has less effect. Excess release of dopamine in the mesolimbic pathway has been linked to psychotic experiences. It has also been proven less dopamine released in the prefrontal cortex in the brain, and excess dopamine released from all other pathways, has also been linked to psychotic experiences, caused by abnormal dopaminergic function as a result of patients suffering from schizophrenia or bipolar disorder. Various neuroleptics such as haloperidol and chlorpromazine suppress dopamine chemicals throughout its pathways, in order for dopamine receptors to function normally.
In addition of the antagonistic effects of dopamine, antipsychotics (in particular atypical neuroleptics) also antagonize 5-HT2A receptors. Different alleles of the 5-HT2A receptor have been associated with schizophrenia and other psychoses, including depression. Higher concentrations of 5-HT2A receptors in cortical and subcortical areas, in particular in the right caudate nucleus have been historically recorded. This is the same receptor that psychedelic drugs agonize to various degrees, which explains the correlation between psychedelic drugs and schizophrenia.
Typical antipsychotics are not particularly selective and also block dopamine receptors in the mesocortical pathway, tuberoinfundibular pathway, and the nigrostriatal pathway. Blocking D2 receptors in these other pathways is thought to produce some unwanted side effects that the typical antipsychotics can produce (see above). They were commonly classified on a spectrum of low potency to high potency, where potency referred to the ability of the drug to bind to dopamine receptors, and not to the effectiveness of the drug. High-potency antipsychotics such as haloperidol, in general, have doses of a few milligrams and cause less sleepiness and calming effects than low-potency antipsychotics such as chlorpromazine and thioridazine, which have dosages of several hundred milligrams. The latter have a greater degree of anticholinergic and antihistaminergic activity, which can counteract dopamine-related side-effects.
Atypical antipsychotic drugs have a similar blocking effect on D2 receptors, however, most also act on serotonin receptors, especially 5-HT2A and 5-HT2C receptors. Both clozapine and quetiapine appear to bind just long enough to elicit antipsychotic effects but not long enough to induce extrapyramidal side effects and prolactin hypersecretion. 5-HT2A antagonism increases dopaminergic activity in the nigrostriatal pathway, leading to a lowered extrapyramidal side effect liability among the atypical antipsychotics.
(OR with 95% CI in brackets)
|Anticholinergic effects||Sedation||EPSE||Weight Gain||Metabolic AEs||QTc prolongation
(ORs & 95% CIs)
|PE||Hypotension||Notes (e.g. notable AEs*)|
|Amisulpride||0.43 (0.32-0.57)||-||-||+||+||+/-||+++ (0.66 [0.39-0.91])||+++/++||-||Torsades de Pointes common on overdose. Has a comparatively low penetrability of the blood-brain barrier.|
|Amoxapine||?||++||++||+/-||++/+||++/+||++/+||++/+||++/+||Amoxapine is also an antidepressant. Very toxic in overdose due to the potential for renal failure and seizures.|
|Aripiprazole||0.61 (0.51-0.72)||-||+||+/- (Akathisia mostly)||+||+/-||- (0.01 [–0.13-0·15])||- (can reduce prolactin levels)||-||Only clinically-utilised antipsychotic that does not act by antagonising the D2 receptor and rather partially agonises this receptor.|
|Asenapine||0.69 (0.54-0.86)||-||++||+||+||+/-||++/+ (0.30 [–0.04-0.65])||+||+||Oral hypoesthesia. Has a complex pharmacologic profile.|
|Blonanserin||~0.7||+||+||++/+||+/-||+/-||-||++/+||+/-||Only used in a few East Asian countries.|
|Chlorpromazine||0.65 (0.5-0.84)||+++||+++||++||++||++||++||+++||+++||First marketed antipsychotic, sort of the prototypical low-potency first-generation (typical) antipsychotic.|
|Clozapine||0.46 (0.32-0.65)||+++||+++||-||+++||+++||+||-||+++||Notable AEs: Agranulocytosis, neutropaenia, leukopaenia and myocarditis. Dose-dependent seizure risk. Overall the most effective antipsychotic, on average. Usually reserved for treatment-resistant cases or highly suicidal patients.|
|Droperidol||?||+/-||+/-||+++||+/-||+/-||?||+++||?||Mostly used for postoperative nausea and vomiting.|
|Flupenthixol||?||++||+||++||++||++||+||+++||+||Also used in lower doses for depression.|
|Fluphenazine||0.69 (0.24-1.97)||++||+||+++||+||+||+||+++||+||High-potency first-generation (typical) antipsychotic.|
|Haloperidol||0.8 (0.71-0.90)||+||+||+++||+||+/-||+ (0.11 [0.03-0.19])||+++||+||Prototypical high-potency first-generation (typical) antipsychotic.|
|Iloperidone||0.69 (0.56-0.84)||-||+/-||+||++||++||++ (0.34 [0.22-0.46])||++/+||+||?|
|Levomepromazine||?||+++||+++||++/+||++||++||?||+++||+++||Also used as an analgesic, agitation, anxiety and emesis.|
|Lurasidone||0.77 (0.61-0.96)||-||-||++/+||-||-||- (–0.10 [–0.21-0.01])||++/+||-||May be particularly helpful in ameloriating the cognitive symptoms of schizophrenia, likely due to its 5-HT7 receptor.|
|Melperone||?||-||+/-||-||+/-||+/-||++||-||++/+||Several smaller low-quality clinical studies have reported its efficacy in the treatment of treatment-resistant schizophrenia. Only approved for use in a few European countries. It is known that off-licence prescribing of melperone is occurring in the United Kingdom. Is a butyrophenone, low-potency atypical antipsychotic that has been tried as a treatment for Parkinson's disease psychosis, although with negative results.|
|Molindone||?||-||++/+||+||-||-||?||+++||+/-||Withdrawn from the market. Seems to promote weight loss (which is rather unique for an antipsychotic seeing how they tend to promote weight gain).|
|Olanzapine||0.46 (0.41-0.52)||+||++||+||+++||+++||+ (0.22 [0.11-0.31])||+||+||?|
|Paliperidone||0.48 (0.39-0.58)||-||-||++/+ (dose-dependent)||++||+||- (0.05 [–0.18-0.26])||+++||++||Active metabolite of risperidone.|
|Perazine||0.62 (0.35-1.10)||?||?||?||?||?||?||?||?||Limited data available on adverse effects.|
|Pericyazine||?||+++||+++||+||++||+||?||+++||++||Also used to treat severe anxiety. Not licensed for use in the US.|
|Perospirone||?||+/-||+||++/+||+/-||?||-||++/+||-||Usually grouped with the atypical antipsychotics despite its relatively high propensity for causing extrapyramidal side effects.|
|Perphenazine||0.40 (0.08-1.90)||+||+||+++||+||+||+||+++||+||Has additional antiemetic effects.|
|Pimozide||0.66 (0.45-0.98)||+||+||+||+||+||+++||+++||+||High potency first-generation (typical) antipsychotic.|
|Pipotiazine||?||++||++||++||++||+||?||+++||++||Only available in the UK.|
|Prochlorperazine||?||?||?||+++||?||?||+||+++||?||Primarily used in medicine as an antiemetic.|
|Quetiapine||0.61 (0.52-0.71)||++/+||++||-||++||++/+||+ (0.17 [0.06-0.29])||-||++||Binds to the D2 receptor in a hit and run fashion. That is it rapidly dissociates from said receptor and hence produces antipsychotic effects but does not bind to the receptor long enough to produce extrapyramidal side effects and hyperprolactinaemia.|
|Remoxipride||?||-||+/-||-||+/-||+/-||-||-||-||Removed from the market amidst concerns about an alarmingly high rate of aplastic anaemia.|
|Risperidone||0.53 (0.46-0.60)||-||++/+ (dose-dependent)||++||++||++/+||++ (0.25 [0.15-0.36])||+++||++||?|
|Sertindole||0.78 (0.61-0.98)||-||-||-||++||++/+||+++ (0.90 [0.76-1.02])||-||+++||Not licensed for use in the US.|
|Sulpiride||1.00 (0.25-4.00)||-||-||+||+||+/-||+||+++/++||-||Not licensed for use in the US.|
|Thioridazine||0.67 (0.32-1.40)||+++||+++||+||++||++||+++||+++||+++||Dose-dependent risk for degenerative retinopathies. Found utility in reducing the resistance of multidrug and even extensively resistant strains of tuberculosis to antibiotics.|
|Ziprasidone||0.72 (0.59 to 0.86)||-||++||+||-||-||++ (0.41 [0.31 to 0.51])||++/+||+||?|
|Zotepine||0.69 (0.41 to 1.07)||+||+++||++||+++/++||+++/++||++||+++||++||Dose-dependent risk of seizures. Not licensed for use in the US.|
|Zuclopenthixol||?||++||++||+++||++||++||?||+++||+||Not licensed for use in the US.|
Note: "Notable" is to mean side-effects that are particularly unique to the antipsychotic drug in question. For example, clozapine is notorious for its ability to cause agranulocytosis. If data on the propensity of a particular drug to cause a particular AE is unavailable an estimation is substituted based on the pharmacologic profile of the drug.
|Generic drug name||Schizophrenia||Mania||Bipolar depression||Bipolar maintenance||Adjunct in major depression|
|Amisulpride||+++||?||?||?||? (+++ in dysthymia)|
|Aripiprazole||++||++||-||++ (prevents manic and mixed but not depressive episodes)||+++|
|Loxapine||+++/++||+++ (only in the treatment of agitation)||?||?||?|
|Olanzapine||+++||+++/++||++||++ (most effective at preventing manic/mixed relapse)||++|
|Ki [nM] toward cloned human receptors (unless otherwise specified)[Note 1]|
|Generic drug name||SERT||5-HT1A||5-HT2A||5-HT2C||5-HT6||5-HT7||α1A||α2A||α2C||NET||D1||D2||D3||D4||5-HT2A/D2||H1||M1||M3|
|Blonanserin||ND||804||0.812||26.4||41.9||183||26.7 (RB)||530 (RC)||ND||ND||1,070||0.142||0.494||150||5.72||765||100||ND|
|cis-Flupenthixol||ND||8,028||87.5 (HFC)||102.2 (RC)||ND||ND||ND||ND||ND||ND||3.5||0.35||1.75||66.3||250||0.86||ND||ND|
|Melperone||ND||2,200 (HB)||230||2,100 (HB)||1,254 (RC)||578 (HB)||180 (HB)||150 (HB)||ND||ND||ND||194||8.95||555||1.186||580||>10,000||>10,000|
|Prochlorperazine||ND||5,900 (HC)||15 (HC)||122||148 (RC)||196 (RC)||23.8 (HB)||1,694.91 (HB)||ND||ND||ND||0.65||2.90||5.40||23.1||18.86 (HB)||555.55 (HB)||ND|
|Norquetiapine||ND||45||48||107||ND||76||144||237||ND||12||99.8 (RC)||196||ND||ND||0.245||3.5||38.3 (RC)||ND|
|Sulpiride||ND||>10,000||>10,000 (RC)||>10,000 (RC)||5,000 (RC)||4,000 (RC)||>10,000 (RB)||4,893 (RB)||ND||ND||>10,000||9.80||8.05||54||>1,000||>10,000 (RB)||>10,000 (RB)||>10,000 (RB)|
|Drug||Bioavailability||t1/2 parent drug
|Protein binding||tmax||Cmax||Vd||Excretion||Routes of administration||Metabolising enzymes||Active metabolites|
|Amisulpride||48%||12 h||16%||3-4 h||54 ± 4 ng/mL||5.8 L/kg||Faeces (20%), urine (50%, when given IV)||Oral||?||None|
|Aripiprazole||87% (Oral), 100% (IM)||75 h (94 h)||99%||3-5 h||?||4.9 L/kg||Faeces (55%), urine (25%)||Oral, IM (including depot)||CYP2D6, CYP3A4||Dehydroaripiprazole|
|Asenapine||35% (sublingual)||24 h||95%||0.5-1.5 h||4 ng/mL||20-25 L/kg||Urine (50%), faeces (40%)||Sublingual||CYP1A2, UGT1A4, CYP2D6||None|
|Blonanserin||55%||10.7-16.2 h (single dosing), 67.9 h (repeated dosing)||≥ 99.7%||1.5-2 h||0.14-0.76 ng/mL (0.57 ng/mL for repeated dosing)||8560-9500 L||Urine (59%), faeces (30%)||Oral||CYP3A4||N-deethylblonanserin|
|Chlorpromazine||20%||30 h||92-97%||?||?||20 L/kg||Urine||Oral, IM, IV||CYP2D6||Several active metabolites|
|Clozapine||50-60%||12 h||97%||1.5-2.5 h||102-771 ng/mL||4.67 L/kg||Urine (50%), faeces (30%)||Oral||CYP1A2, CYP2D6, CYP3A4||Norclozapine|
|Droperidol||?||2 h (8-12 h)||Extensive||60 min (IM)||?||2 L/kg (adults), 0.58 L/kg (children)||Urine (75%), faeces (22%)||IM, IV||?||None|
|Flupentixol||40-55% (Oral)||35 h||?||7 days (depot)||?||12-14 L/kg||Urine||Oral, IM (including depot)||?||None|
|Fluphenazine||2.7% (Oral)||14-16 h, 14 days (depot)||?||2 h (Oral), 8-10 h (depot)||?||?||Urine, faeces||Oral, IM (including depot)||?||None|
|Haloperidol||60-70% (Oral)||10-20 h (short-acting IM), 3 weeks (depot)||92%||2-6 h (Oral), 10-20 min (short-acting IM), 6–7 days (depot)||?||8-18 L/kg||Urine (30%), faeces (15%)||Oral, IM, IV||CYP3A4||None|
|Iloperidone||96%||?||95%||2-4 h||?||1340-2800 L||Urine (45-58%), faeces (20-22%)||Oral||CYP3A4, CYP2D6||None notable.|
|Levomepromazine||?||30 h||?||2-3 h||?||?||Urine, faeces||IM, IV||?||Methotrimeprazine sulfoxide|
|Loxapine||High||6-8 h (Inhaled), 4-12 h (Oral)||96.6%||2 min (inhaled), 2 h (oral), 5 h (IM)||257 ng/mL (inhaled), 6-13 ng/mL (Oral)||?||Urine (56-70%), faeces [Only oral data available]||Oral, IM, Inhalation||CYP1A2, CYP3A4, CYP2D6||Amoxapine (a tricyclic antidepressant), 7-OH loxapine, 8-OH loxapine|
|Lurasidone||9-19%||18 h||99%||1-3 h||?||6173 L||Urine (9%), faeces (80%)||Oral||CYP3A4||2 active|
|Melperone||54% (Oral via syrup), 65% (Oral via tablets), 87% (IM)||2.1-6.4 h (Oral), 6.6 ± 3.7 h (IM)||50%||1.6-2.4 h (Oral, tablets), 1 h (Oral, syrup)||1132 ± 814 ng/mL (25 mg, orally), 2228-3416 ng/mL (50 mg, orally), 89539 ± 37001 ng/mL (100 mg, orally)||9.9 ± 3.7 L/kg (10 mg), 7 ± 1.61 L/kg (20 mg)||Urine (70% as metabolites, 5.5-10.4% as parent drug)||Oral, IM||?||None|
|Olanzapine||87% (Oral)||30 h||93%||6 h (Oral), 15-45 min (short-acting IM), 7 days (depot)||4-20.4 mg/mL||1000 L||Urine (57%), faeces (30%)||Oral, IM (including depot)||CYP1A2||None|
|Paliperidone||28% (Oral)||23 h (Oral), 25–49 days (IM)||74%||24 h (Oral), 13 days (IM)||8.85-11.7 ng/mL||390-487 L||Urine (80%), faeces (11%)||Oral, IM (depot)||CYP3A4, CYP2D6||None|
|Periciazine||?||12 h||?||2 h||150 ng/mL||?||Urine||Oral||?||?|
|Perospirone||?||1.9-2.5 h||92%||1.5 h||5.7 ng/mL||?||Urine (0.4% as unchanged drug)||Oral||?||None|
|Perphenazine||?||9-12 h (10-19 h)||?||1-3 h; 2-4 h (metabolite)||0.984 ng/mL; 0.509 ng/mL||?||Urine, faeces||Oral||CYP2D6||7-OH perphenazine|
|Pimozide||40-50%||55 h||?||6-8 h||4-19 ng/mL (dose-dependent)||?||Urine||Oral||CYP3A4, CYP2D6||None|
|Prochlorperazine||12.5%||6.8-9 h||High||?||?||12.9-17.7 L/h||Urine, bile||Oral, IM, IV||?||N-desmethylprochlorperazine|
|Quetiapine||100%||6 h (IR), 7 h (XR); active metabolite: 12 h||83%||1.5 h (IR), 6 h (XR)||@ 250 mg q8hr 778 ng/mL (male), 879 ng/mL (female)||6-14 L/kg||Urine (73%), faeces (20%)||Oral||CYP3A4||Norquetiapine (a norepinephrine reuptake inhibitor and 5-HT1A receptor partial agonist)|
|Risperidone||70%||3-17 h (24 h)||90% (active metabolite: 77%)||3-17 h||?||1-2 L/kg||Urine (70%), faeces (14%)||Oral, IM (including depot)||CYP2D6||Paliperidone|
|Sertindole||?||3 days||99.5%||10 h||?||20 L/kg||Urine (4%), faeces (46-56%)||Oral||CYP2D6||None|
|Sulpiride||27 ± 9%||8 h||40%||3-6 h||?||2.72 ± 0.66 L/kg||Urine, faeces||Oral||?||None|
|Ziprasidone||60% (Oral), 100% (IM)||7 h (Oral), 2-5 h (IM)||99%||6-8 h (Oral), ≤ 60 min (IM)||?||1.5 L/kg||Faeces (66%), urine (20%)||Oral, IM||CYP3A4, CYP1A2||None|
|Zotepine||7-13%||13.7-15.9 h (12 h)||97%||1-4 h||31-240||10 L/kg||Urine (17%)||Oral||CYP1A2, CYP3A4||Norzotepine (a norepinephrine reuptake inhibitor)|
|Zuclopenthixol||49%||20 h||98%||2-12 h (mean: 4 h)||?||20 L/kg||Faeces, urine (10%)||Oral, IM (including depot)||CYP2D6||None|
The original antipsychotic drugs were happened upon largely by chance and then tested for their effectiveness. The first, chlorpromazine, was developed as a surgical anesthetic. It was first used on psychiatric patients because of its powerful calming effect; at the time it was regarded as a non-permanent "pharmacological lobotomy". Lobotomy at the time was used to treat many behavioral disorders, including psychosis, although its effect was to markedly reduce behavior and mental functioning of all types. However, chlorpromazine proved to reduce the effects of psychosis in a more effective and specific manner than lobotomy, even though it was known to be capable of causing severe sedation. The underlying neurochemistry involved has since been studied in detail, and subsequent antipsychotic drugs have been discovered by an approach that incorporates this sort of information.
The discovery of chlorpromazine's psychoactive effects in 1952 led to greatly reduced use of restraint, seclusion, and sedation in the management of agitated patients, and also led to further research that resulted in the development of antidepressants, anxiolytics, and the majority of other drugs now used in the management of psychiatric conditions. In 1952, Henri Laborit described chlorpromazine only as inducing indifference towards what was happening around them in nonpsychotic, nonmanic patients, and Jean Delay and Pierre Deniker described it as controlling manic or psychotic agitation. The former claimed to have discovered a treatment for agitation in anyone, and the latter team claimed to have discovered a treatment for psychotic illness.
Until the 1970s there was considerable debate within psychiatry on the most appropriate term to use to describe the new drugs. In the late 1950s the most widely used term was "neuroleptic", followed by "major tranquilizer" and then "ataraxic". The first recorded use of the term tranquilizer dates from the early nineteenth century. In 1953 Frederik F. Yonkman, a chemist at the Swiss based Cibapharmaceutical company, first used the term tranquilizer to differentiate reserpine from the older sedatives. The wordneuroleptic was derived from the Greek: "νεῦρον"(neuron, originally meaning "sinew" but today referring to the nerves) and "λαμβάνω" (lambanō, meaning "take hold of"). Thus, the word means taking hold of one's nerves. This may refer to common side effects such as reduced activity in general, as well as lethargy and impaired motor control. Although these effects are unpleasant and in some cases harmful, they were at one time, along with akathisia, considered a reliable sign that the drug was working. The term "ataraxy" was coined by the neurologist Howard Fabing and the classicist Alister Cameron to describe the observed effect of psychic indifference and detachment in patients treated with chlorpromazine. This term derived from the Greek adjective "ἀτάρακτος" (ataraktos), which means "not disturbed, not excited, without confusion, steady, calm". In the use of the terms "tranquilizer" and "ataractic", medical practitioners distinguished between the "major tranquilizers" or "major ataractics", which referred to drugs used to treat psychoses, and the "minor tranquilizers" or "minor ataractics", which referred to drugs used to treat neuroses. While popular during the 1950s, these terms are infrequently used today. They are being abandoned in favor of "antipsychotic", which refers to the drug's desired effects. Today, "minor tranquilizer" can refer to anxiolytic and/or hypnotic drugs such as the benzodiazepines and nonbenzodiazepines, which have some antipsychotic properties and are recommended for concurrent use with antipsychotics, and are useful for insomnia or drug-induced psychosis. They are powerful (and potentially addictive) sedatives.
Antipsychotics are broadly divided into two groups, the typical or first-generation antipsychotics and the atypical or second-generation antipsychotics. The typical antipsychotics are classified according to their chemical structure while the atypical antipsychotics are classified according to their pharmacological properties. These include serotonin-dopamine antagonists (seedopamine antagonist and serotonin antagonist), multi-acting receptor-targeted antipsychotics (MARTA, those targeting several systems), and dopamine partial agonists, which are often categorized as atypicals.
Antipsychotics were once among the biggest selling and most profitable of all drugs, generating $22 billion in global sales in 2008. By 2003 in the US, an estimated 3.21 million patients received antipsychotics, worth an estimated $2.82 billion. Over 2/3 of prescriptions were for the newer more expensive atypicals, each costing on average $164 compared to $40 for the older types. By 2008, sales in the US reached $14.6 billion, the biggest selling drugs in the US by therapeutic class.
Antipsychotics are sometimes administered as part of compulsory psychiatric treatment via inpatient (hospital) commitment or outpatient commitment. They may be administered orally or, in some cases, through long-acting (depot) injections administered in the dorsgluteal, ventrogluteal or deltoid muscle.
According to The Guardian newspaper: "At the heart of years of dissent against psychiatry through the ages has been its use of drugs, particularly antipsychotics, to treat distress. Do such drugs actually target any "psychiatric condition"? Or are they chemical control—a socially-useful reduction of the paranoid, deluded, distressed, bizarre and odd into semi-vegetative zombies?"
Some argue that the evidence for antipsychotics from discontinuation-relapse studies may be flawed, because they do not take into account that antipsychotics may sensitize the brain and provoke psychosis if discontinued, which may then be wrongly interpreted as a relapse of the original condition. Evidence from comparison studies indicates that there may be a subset of individuals with schizophrenia who recover from psychosis without taking antipsychotics, and may do better in the long term than those that do take antipsychotics.
Use of this class of drugs has a history of criticism in residential care. As the drugs used can make patients calmer and more compliant, critics claim that the drugs can be overused. Outside doctors can feel under pressure from care home staff. In an official review commissioned by UK government ministers it was reported that the needless use of anti-psychotic medication in dementia care was widespread and was linked to 1800 deaths per year. In the US, the government has initiated legal action against the pharmaceutical company Johnson & Johnson for allegedly paying kickbacks to Omnicare to promote its antipsychotic risperidone (Risperdal) in nursing homes.
There is some controversy over maintenance therapy for schizophrenia. A review of studies about maintenance therapy concluded that long-term antipsychotic treatment was superior to placebo in reducing relapse in individuals with schizophrenia, although some of the studies were small. A review of major longitudinal studies in North America found that a moderate number of patients with schizophrenia were seen to recover over time from their symptoms, raising the possibility that some patients may not require maintenance medication. It has also been argued that much of the research into long-term antipsychotic maintenance may be flawed due to failure to take into account the role of antipsychotic withdrawal effects on relapse rates.
There has also been controversy about the role of pharmaceutical companies in marketing and promoting antipsychotics, including allegations of downplaying or covering up adverse effects, expanding the number of conditions or illegally promoting off-label usage; influencing drug trials (or their publication) to try to show that the expensive and profitable newer atypicals were superior to the older cheaper typicals that were out of patent. Following charges of illegal marketing, settlements by two large pharmaceutical companies in the US set records for the largest criminal fines ever imposed on corporations. One case involved Eli Lilly and Company's antipsychotic Zyprexa, and the other involved Bextra. In the Bextra case, the government also charged Pfizer with illegally marketing another antipsychotic, Geodon. In addition, Astrazeneca faces numerous personal-injury lawsuits from former users of Seroquel (quetiapine), amidst federal investigations of its marketing practices. By expanding the conditions for which they were indicated, Astrazeneca's Seroquel and Eli Lilly's Zyprexa had become the biggest selling antipsychotics in 2008 with global sales of $5.5 billion and $5.4 billion respectively.
Harvard medical professor Joseph Biederman conducted research on bipolar disorder in children that led to an increase in such diagnoses. A 2008 Senate investigation found that Biederman also received $1.6 million in speaking and consulting fees between 2000 and 2007 — some of them undisclosed to Harvard — from companies including makers of antipsychotic drugs prescribed for children with bipolar disorder. Johnson & Johnson gave more than $700,000 to a research center that was headed by Biederman from 2002 to 2005, where research was conducted, in part, on Risperdal, the company's antipsychotic drug. Biederman has responded saying that the money did not influence him and that he did not promote a specific diagnosis or treatment.
Pharmaceutical companies have also been accused of attempting to set the mental health agenda through activities such as funding consumer advocacy groups.
Antipsychotics are intended to treat psychotic disorders. However, they are frequently used as a first-line treatment for other conditions in vulnerable populations.
Evidence indicates that antipsychotics should not be used in children or adolescents as a first-line treatment for anything other than a psychotic disorder. In a concerning trend, in the United States since 2000 the usage of these drugs in young people has greatly increased especially among children from low-income families. Evidence for the efficacy and tolerability of antipsychotic medications is not sufficient to be able to anticipate all the risks, which include young peoples' tendency toward weight gain, metabolic side effects, and cardiovascular changes.
It is recommended that persons with dementia who exhibit behavioral and psychological symptoms should not be given antipsychotics before trying other treatments. When taking antipsychotics this population has increased risk of cerebrovascular effects, parkinsonism or extrapyramidal symptoms, sedation, confusion and other cognitive adverse effects, weight gain, and increased mortality. Physicians and caretakers of persons with dementia should try to address symptoms including agitation, aggression, apathy, anxiety, depression, irritability, and psychosis with alternative treatments whenever antipsychotic use can be replaced or reduced. Elderly persons often have their dementia treated first with antipsychotics and this is not best.
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