risperidone risperidone risperidone, sold under the brand name risperdal among others, is an atypical antipsychotic used to treat schizophrenia and bipolar disorder. it is taken either by mouth or by injection (subcutaneous or intramuscular). the injectable versions are long-acting and last for 2–4 weeks. not to be confused with reserpine. risperidoneclinical datatrade namesrisperdal, okedi, othersahfs/drugs.commonographmedlineplusa694015license data us dailymed: risperidone pregnancycategory au: c routes ofadministrationby mouth, intramuscular, subcutaneousdrug classatypical antipsychoticatc coden05ax08 (who) legal statuslegal status au: s4 (prescription only) ca: ℞-only uk: pom (prescription only) us: ℞-only eu: rx-only pharmacokinetic databioavailability70% (by mouth)metabolismliver (cyp2d6 mediated to 9-hydroxyrisperidone)elimination half-life20 hours (by mouth), 3–6 days (im)excretionurinary (70%) feces (14%)identifiers iupac name 3-ethyl]-2-methyl-6,7,8,9-tetrahydropyridopyrimidin-4-one cas number106266-06-2 ypubchem cid5073pubchem sid475100iuphar/bps96drugbankdb00734 ychemspider4895 yuniil6uh7zf8hckeggd00426 ychebichebi:8871 ychemblchembl85 ypdb ligand8nu (pdbe, rcsb pdb)comptox dashboard (epa)dtxsid8045193 echa infocard100.114.705 chemical and physical dataformulac23h27fn4o2molar mass410.493 g·mol−13d model (jsmol)interactive image smiles cc1c(c(=o)n2c(n1)cccc2)ccn3ccc(cc3)c4c5ccc(cc5on4)f inchi inchi=1s/c23h27fn4o2/c1-15-18(23(29)28-10-3-2-4-21(28)25-15)9-13-27-11-7-16(8-12-27)22-19-6-5-17(24)14-20(19)30-26-22/h5-6,14,16h,2-4,7-13h2,1h3 ykey:rapzeapathnipo-uhfffaoysa-n y (verify) common side effects include movement problems, sleepiness, dizziness, trouble seeing, constipation, and increased weight. serious side effects may include the potentially permanent movement disorder tardive dyskinesia, as well as neuroleptic malignant syndrome, an increased risk of suicide, and high blood sugar levels. in older people with psychosis as a result of dementia, it may increase the risk of death. it is unknown if it is safe for use in pregnancy. its mechanism of action is not entirely clear, but is believed to be related to its action as a dopamine and serotonin antagonist. study of risperidone began in the late 1980s and it was approved for sale in the united states in 1993. it is on the world health organization's list of essential medicines. it is available as a generic medication. in 2020, it was the 138th most commonly prescribed medication in the united states, with more than 4 million prescriptions. medical uses risperidone is mainly used for the treatment of schizophrenia, bipolar disorder, and irritability associated with autism. schizophrenia risperidone is effective in treating psychogenic polydipsia and the acute exacerbations of schizophrenia. 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. 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. 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. a 2011 cochrane review compared risperidone with other atypical antipsychotics such as olanzapine for schizophrenia: summary risperidone seems to produce somewhat more extrapyramidal side effects and clearly more prolactin increase than other atypical antipsychotics. it may also differ from other compounds in the occurrence of other adverse effects such as weight gain, metabolic problems, cardiac effects, sedation, and seizures. nevertheless, the large proportion of participants leaving studies early and incomplete reporting of outcomes makes drawing firm conclusions difficult. outcome findings in words findings in numbers quality of evidence global state no clinically significant responserisperidone is not clearly different when compared to olanzapine. data supporting this finding are based on moderate-quality evidence. rr 1.06 (0.99 to 1.13)moderate leaving the study early due to any reasonrisperidone probably slightly increases the chance of leaving the study early, when compared with olanzapine. data are based on moderate quality evidence. rr 1.14 (1.07 to 1.21)moderate service outcome number of patients rehospitalizedfollow-up: up to 12 weeksno clear difference is seen between risperidone and olanzapine for the outcome of how much hospital/community care is used. these findings are based on data of low quality. rr 1.35 (0.41 to 4.40)low mental state average panss score (high = poor)follow-up: up to 12 weekson average, people receiving risperidone scored slightly higher (worse) than people treated with olanzapine but there was no clear difference between the groups. the meaning of this in day-to-day care is unclear. this finding is based on data of low quality.md 0.97 higher (1.1 lower to 3.05 higher)low adverse effects at least one adverse effectthere was no clear difference between risperidone and olanzapine for this very general adverse effect outcome. these findings are based on data of low quality. rr 0.96 (0.88 to 1.03)low quality of life average qls scale score (high = poor)follow-up: over 26 weekson average, people receiving risperidone scored higher than people treated with olanzapine. there was no clear difference between the groups. the meaning of this in day-to-day care is unclear. this finding is based on data of moderate quality.md 0.97 higher (1.1 lower to 3.05 higher)moderate long-acting injectable formulations of antipsychotic drugs provide improved compliance with therapy and reduce relapse rates relative to oral formulations. the efficacy of risperidone long-acting injection appears to be similar to that of long acting injectable forms of first generation antipsychotics. bipolar disorder second-generation antipsychotics, including risperidone, are effective in the treatment of manic symptoms in acute manic or mixed exacerbations of bipolar disorder. in children and adolescents, risperidone may be more effective than lithium or divalproex, but has more metabolic side effects. as maintenance therapy, long-acting injectable risperidone is effective for the prevention of manic episodes but not depressive episodes. 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. autism compared to placebo, risperidone treatment reduces certain problematic behaviors in autistic children, including aggression toward others, self-injury, challenging behaviour, and rapid mood changes. the evidence for its efficacy appears to be greater than that for alternative pharmacological treatments. weight gain is an important adverse effect. 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. evidence for the efficacy of risperidone in autistic adolescents and young adults is less persuasive. 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. because of this increased risk of death, treatment of dementia-related psychosis with risperidone is not fda approved and carries a black box warning. 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. other uses risperidone has shown promise in treating therapy-resistant obsessive-compulsive disorder, when serotonin reuptake inhibitors alone are not sufficient. risperidone has proven to be effective in treatment with attention deficit hyperactivity disorder especially in cases of aggression or with another mental condition. risperidone has not demonstrated a benefit in the treatment of eating disorders or personality disorders, except for limited evidence in schizotypal personality disorder. forms available forms of risperidone include tablet, oral dissolving tablet, oral solution, and powder and solvent for suspension for injection. adverse effects