Schizophrenia

Risperidone is effective in treating psychogenic polydipsia and the acute exacerbations of schizophrenia.^[16][17]

Studies evaluating the utility of risperidone by mouth for maintenance therapy have reached varying conclusions. A 2012 systematic review concluded that evidence is strong that risperidone is more effective than all first-generation antipsychotics other than haloperidol, but that evidence directly supporting its superiority to placebo is equivocal.^[18] A 2011 review concluded that risperidone is more effective in relapse prevention than other first- and second-generation antipsychotics with the exception of olanzapine and clozapine.^[19] A 2016 Cochrane review suggests that risperidone reduces the overall symptoms of schizophrenia, but firm conclusions are difficult to make due to very low-quality evidence. Data and information are scarce, poorly reported, and probably biased in favour of risperidone, with about half of the included trials developed by drug companies. The article raises concerns regarding the serious side effects of risperidone, such as parkinsonism.^[20] A 2011 Cochrane review compared risperidone with other atypical antipsychotics such as olanzapine for schizophrenia:^[21]

Long-acting injectable formulations of antipsychotic drugs provide improved compliance with therapy and reduce relapse rates relative to oral formulations.^[22][23] The efficacy of risperidone long-acting injection appears to be similar to that of long-acting injectable forms of first-generation antipsychotics.^[24]

Bipolar disorder

Second-generation antipsychotics, including risperidone, are effective in the treatment of manic symptoms in acute manic or mixed exacerbations of bipolar disorder.^[25][26][27] In children and adolescents, risperidone may be more effective than lithium or divalproex, but has more metabolic side effects.^[28] As maintenance therapy, long-acting injectable risperidone is effective for the prevention of manic episodes but not depressive episodes.^[29] The long-acting injectable form of risperidone may be advantageous over long-acting first-generation antipsychotics, as it is better tolerated (fewer extrapyramidal effects) and because long acting injectable formulations of first-generation antipsychotics may increase the risk of depression.^[30]

Autism

Compared to placebo, risperidone treatment reduces certain problematic behaviors in autistic children, including aggression toward others, self-injury, challenging behavior, and rapid mood changes.^[31] The evidence for its efficacy appears to be greater than that for alternative pharmacological treatments.^[32] Weight gain is an important adverse effect.^[7][33] Some authors recommend limiting the use of risperidone and aripiprazole to those with the most challenging behavioral disturbances in order to minimize the risk of drug-induced adverse effects.^[34] Evidence for the efficacy of risperidone in autistic adolescents and young adults is less persuasive.^[35]

Dementia

While antipsychotic medications such as risperidone have a slight benefit in people with dementia, they have been linked to higher incidence of death and stroke.^[36] Because of this increased risk of death, treatment of dementia-related psychosis with risperidone is not FDA approved and carries a black box warning.^[7] However, many other jurisdictions regularly use it to control severe aggression and psychosis in those with dementia when other non-pharmacological interventions have failed and their pharmaceutical regulators have approved its use in this population.^[37][38]

Other uses

Risperidone has demonstrated clinical benefit as an augmentation agent in the management of (unipolar) non-psychotic treatment-resistant depression alongside antidepressant treatment.^[39] Atypical antipsychotics, such as risperidone, are among the most common augments for antidepressant therapy. Such usage occurs "off-label" in most jurisdictions and the risk of adverse effects (e.g., weight gain, movement disorders) must be carefully weighed against the clinical benefit.^[40]

Risperidone has shown promise in treating therapy-resistant obsessive-compulsive disorder, when serotonin reuptake inhibitors alone are not sufficient.^[41]

Risperidone has proven to be effective in treatment with attention deficit hyperactivity disorder especially in cases of aggression^[42][43] or with another mental condition.^[44]

Risperidone has not demonstrated a benefit in the treatment of eating disorders or personality disorders, except for limited evidence in schizotypal personality disorder.^[36]

Forms

Available forms of risperidone include tablet, oral dissolving tablet, oral solution, and powder and solvent for suspension for injection.^[45]

Drug interactions

• Carbamazepine and other enzyme inducers may reduce plasma levels of risperidone.^[7] If a person is taking both carbamazepine and risperidone, the dose of risperidone will likely need to be increased. The new dose should not be more than twice the patient's original dose.^[7]
• CYP2D6 inhibitors, such as SSRI medications, may increase plasma levels of risperidone and those medications.^[7]
• Since risperidone can cause hypotension, its use should be monitored closely when a patient is also taking antihypertensive medicines to avoid severe low blood pressure.^[7]
• Risperidone and its metabolite paliperidone are reduced in efficacy by P-glycoprotein inducers such as St John's wort.^[49][50]

Discontinuation

The British National Formulary recommends a gradual withdrawal when discontinuing antipsychotic treatment to avoid acute withdrawal syndrome or rapid relapse.^[51]

Dementia

Older people with dementia-related psychosis are at a higher risk of death.^[7]

Pharmacodynamics

Risperidone has been classified as a "qualitatively atypical" antipsychotic agent with a relatively low incidence of extrapyramidal side effects (when given at low doses) that has more pronounced serotonin antagonism than dopamine antagonism. Risperidone contains the functional groups of benzisoxazole and piperidine as part of its molecular structure. Although not a butyrophenone, it was developed with the structures of benperidol and ketanserin as a basis. It has actions at several 5-HT (serotonin) receptor subtypes. These are 5-HT_2C, linked to weight gain, 5-HT_2A, linked to its antipsychotic action and relief of some of the extrapyramidal side effects experienced with the typical neuroleptics.^[54]

It has been found that D-amino acid oxidase, the enzyme that catalyses the breakdown of D-amino acids (e.g. D-alanine and D-serine — the neurotransmitters) is inhibited by risperidone.^[55]

Risperidone acts on the following receptors:

Dopamine receptors: This drug is an antagonist of the D₁ (D₁, and D₅) as well as the D₂ family (D₂, D₃ and D₄) receptors, with 70-fold selectivity for the D₂ family. It has "tight binding" properties, which means it has a long half-life. Like other antipsychotics, risperidone blocks the mesolimbic pathway, the prefrontal cortex limbic pathway, and the tuberoinfundibular pathway in the central nervous system. Risperidone may induce extrapyramidal side effects, akathisia and tremors, associated with diminished dopaminergic activity in the striatum. It can also cause sexual side effects, galactorrhoea, infertility, gynecomastia and, with chronic use reduced bone mineral density leading to breaks, all of which are associated with increased prolactin secretion.^[54]

Serotonin receptors: Most important pharmalogical function is to compensate dopamine blocking.^{[medical citation needed]}

Alpha α₁ adrenergic receptors: This action accounts for the orthostatic hypotensive effects and perhaps some of the sedating effects of risperidone.^[54]

Alpha α₂ adrenergic receptors: Risperidone's action at these receptors may cause greater positive, negative, affective, and cognitive symptom control.^[56]

Histamine H₁ receptors: effects on these receptors account for its sedation and reduction in vigilance. This may also lead to drowsiness and weight gain.^[54]

Voltage-gated sodium channels: Because it accumulates in synaptic vesicles, Risperidone inhibits voltage-gated sodium channels at clinically used concentrations.^[57]

Pharmacokinetics

Risperidone undergoes hepatic metabolism and renal excretion. Lower doses are recommended for patients with severe liver and kidney disease.^[7] The active metabolite of risperidone, paliperidone, is also used as an antipsychotic.^{[58][unreliable medical source?]}

Legal status

Risperidone was approved by the United States Food and Drug Administration (FDA) in 1993 for the treatment of schizophrenia.^[69] In 2003, the FDA approved risperidone for the short-term treatment of the mixed and manic states associated with bipolar disorder. In 2006, the FDA approved risperidone for the treatment of irritability in autistic children and adolescents.^[70] The FDA's decision was based in part on a study of autistic people with severe and enduring problems of violent meltdowns, aggression, and self-injury; risperidone is not recommended for autistic people with mild aggression and explosive behavior without an enduring pattern.^[71] On 22 August 2007, risperidone was approved as the only drug agent available for treatment of schizophrenia in youths, ages 13–17; it was also approved that same day for treatment of bipolar disorder in youths and children, ages 10–17, joining lithium.

On 16 December 2021, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) adopted a positive opinion, recommending the granting of a marketing authorization for the medicinal product Okedi, intended for the treatment of schizophrenia in adults for whom tolerability and effectiveness has been established with oral risperidone.^[72] The applicant for this medicinal product is Laboratorios Farmacéuticos Rovi, S.A.^[72] Risperidone was approved for medical use in the European Union in February 2022.^[8][73]

Lawsuits

In April 2012, Johnson & Johnson (J&J) and its subsidiary Janssen Pharmaceuticals Inc. were fined $1.2 billion for downplaying multiple risks associated with risperidone.^[74] The verdict was later reversed by the Arkansas state supreme court.^[75]

In August 2012, J&J agreed to pay $181 million to 36 US states in order to settle claims that it had promoted risperidone and paliperidone for off-label uses including for dementia, anger management, and anxiety.^[76]

In November 2013, J&J was fined $2.2 billion for illegally marketing risperidone for use in people with dementia.^[77]

In 2015, Steven Brill wrote an investigative journalism piece about J&J in The Huffington Post focused on J&J's marketing of risperidone.^[78][79]

J&J has faced numerous civil lawsuits on behalf of children who were prescribed risperidone who grew breasts (a condition called gynecomastia); as of July 2016 there were about 1,500 cases in Pennsylvania state court in Philadelphia, and there had been a February 2015 verdict against J&J with $2.5 million awarded to a man from Alabama, a $1.75 million verdict against J&J that November, and in 2016 a $70 million verdict against J&J.^[80] In October 2019, a jury awarded a Pennsylvania man $8 billion in a verdict against J&J.^[81]

Brand names

Janssen's patent on risperidone expired in December 2003, opening the market for cheaper generic versions from other companies, and Janssen's exclusive marketing rights expired in June 2004 (the result of a pediatric extension). It is available under many brand names worldwide.^[1]

Risperidone is available as a tablet, an oral solution, and an ampule, which is a depot injection.^[1]

Brand names include Risperdal, Risperdal Consta, Risperdal M-Tab, Risperdal Quicklets, Risperlet, Okedi, and Perseris.^[82]