Risperidone
Risperidone
Definition
Risperidone is classified as an atypical antipsychotic drug. It is sold in the United States under the brand name of Risperdal.
Purpose
Risperidone is used for the management of symptoms of psychotic disorders such as schizophrenia.
Description
Risperidone is an atypical antipsychotic agent for two reasons. First, it is chemically unrelated to the older antipsychotic drugs. Second, unlike older anti-psychotic drugs that primarily inhibit the actions of dopamine, a chemical in the brain, risperidone may also have some action against another brain chemical, serotonin. The proper level of both dopamine and serotonin are influential in maintaining mental well-being.
An advantage of using risperidone over one of the older antipsychotic drugs is a lower incidence of par-kinsonian-like side effects. These side effects may be
sufficiently troublesome, causing patients to discontinue treatment for their schizophrenia. For this reason, patients who have had negative experiences with older antipsychotics may benefit from risperidone. Also, some patients who showed little improvement with older antipsychotic drugs respond better to risperidone.
Recently, the effectiveness of risperidone was evaluated in the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) Schizophrenia Study. This study evaluated the effectiveness and side effects of newer antipsychotic drugs (sometimes referred to as atypical antipsychotics)—including risperidone—in comparison to a conventional antipsychotic drug in the treatment of schizophrenia.
Contrary to expectations, the study found that the conventional antipsychotic generally was equally effective and tolerated as well as the newer, more expensive, atypical antipsychotic medications. The study also showed that risperidone and olanzapine tend to be better tolerated than the other atypical antipsychotics investigated, although only 35% of participants on risperidone were able to continue taking it throughout the entire 18 months of the study. Participants who stopped taking their antipsychotic medication in Phase 1 because it was not adequately controlling their symptoms were more likely to stay on their medication if they were switched to risperidone or olanzapine than to quetiapine or ziprasidone. There was no difference between the four medications tested in Phase 2, however, for participants who had stopped taking their Phase 1 medication because they experienced adverse side effects.
In Phase 2 of the study, clozapine was more effective in controlling symptoms than the other atypical antipsychotics under evaluation. For patients whose symptoms are not well controlled on clozapine, risperidone and olanzapine tend to be more effective than ziprasidone or quetiapine.
The CATIE study did not reveal a clear path of next treatment for those patients who had discontinued use of an antipsychotic due to adverse side effects. In such cases, it is important to balance the degree of symptom control from the drug with the nature of its side effects. Of the drugs evaluated, risperidone had the least adverse side effects.
Recommended dosage
Risperidone is available in 0.25-mg, 0.5-mg, 1-mg, 2-mg, 3-mg, and 4-mg tablets and a solution containing 1 mg of drug in each milliliter of solution. For treating psychotic disorders in adults, the usual starting dose of risperidone is 1 mg twice daily. Dosage is increased gradually until a target dose of 3 mg twice
daily is reached. Some patients do just as well with a single daily dose (6 mg once a day, for example). There is little clinical evidence to indicate that increasing the daily dose beyond 8 mg offers additional benefit. However, higher doses may contribute to additional side effects. If the dose needs to be adjusted, the changes should be made no more often than once per week.
In older patients (over age 60), starting dosage should not exceed 1 mg daily. Most patients should not take more than 3 mg daily. People with low blood pressure and those who have kidney disease should take a similarly reduced dose.
Precautions
Patients with a history of cardiovascular disease or low blood pressure should take risperidone only after discussing the risks and benefits with their physicians, and then with close physician monitoring.
Risperidone has occasionally been associated with seizures. People with a past history of seizures should discuss with their doctors whether risperidone is the right antipsychotic for them to use.
People taking risperidone should avoid operating a motor vehicle or other dangerous machinery until they see how risperidone affects them.
Some people have trouble regulating their body temperatures while taking risperidone. Patients receiving this drug should be aware of this and avoid extremes in outdoor temperatures.
Side effects
The most common and bothersome side effect associated with risperidone is decreased blood pressure while standing up (known as orthostatic hypotension). This can cause dizziness or fainting. A decrease in blood pressure usually occurs early in therapy, while the proper dose is being established. It is more common in older patients than in younger ones. Usually this side effect disappears entirely with time. If it continues, the physician may decrease the dose. Meanwhile, people taking risperidone should be aware of this side effect and get up slowly if they have been sitting for an extended time.
The most common nervous system side effects of risperidone include insomnia, agitation, anxiety, and headache. Early in therapy, patients may experience an inability to think clearly or perform certain tasks that require mental alertness. High doses of risperidone can cause unwanted sleepiness in about 40% of patients.
KEY TERMS
Antipsychotic —A medication used to treat psychotic symptoms of schizophrenia such as hallucinations, delusions, and delirium. Antipsychotics may be used to treat symptoms in other disorders as well.
Atypical antipsychotic —A newer antipsychotic drug that is less likely to cause significant adverse side effects than conventional antipsychotic medications. Atypical antipsychotics are also called novel antipsychotics or second-generation antipsychotics.
Dopamine —A chemical in brain tissue that serves to transmit nerve impulses (is a neurotransmitter) and helps to regulate movement and emotions.
Parkinsonian —Related to symptoms associated with Parkinson’s disease, a nervous system disorder characterized by abnormal muscle movement of the tongue, face, and neck, inability to walk or move quickly, walking in a shuffling manner, restlessness, and/or tremors.
Serotonin —A widely distributed neurotransmitter that is found in blood platelets, the lining of the digestive tract, and the brain, and that works in combination with norepinephrine. It causes very powerful contractions of smooth muscle, and is associated with mood, attention, emotions, and sleep. Low levels of serotonin are associated with depression.
Antipsychotic drugs, including risperidone, can cause side effects that are similar to the symptoms of Parkinson’s disease. The patient does not have Parkinson’s disease, but may have shaking in muscles at rest, difficulty with voluntary movements, and poor muscle tone. These symptoms are similar to the symptoms of Parkinson’s disease. They normally disappear if the drug is stopped.
The most common gastrointestinal side effects include nausea, vomiting, constipation, and difficulty digesting food.
Up to 10% of patients taking risperidone experience rhinitis (runny nose).
Interactions
There is very little information about how risperidone interacts with other drugs. However, because some patients receiving risperidone experience lowered blood pressure while standing, it is expected that other drugs that lower blood pressure may increase the incidence and severity of this side effect when taken with risperidone.
Resources
BOOKS
American Society of Health-System Pharmacists. AHFS Drug Information 2002. Bethesda: American Society of Health-System Pharmacists, 2002.
Preston, John D., John H. O’Neal, and Mary C. Talaga. Handbook of Clinical Psychopharmacology for Therapists. 4th ed. Oakland, CA: New Harbinger Publications, 2004.
PERIODICALS
Casey, Daniel E. “Implications of the CATIE Trial on Treatment: Extrapyramidal Symptoms.” CNS Spectrums 11.7, Supp. 7 (July 2006): 25–31.
Gentile, Salvatore. “Extrapyramidal Adverse Events Associated with Atypical Antipsychotic Treatment of Bipolar Disorder.” Journal of Clinical Psychopharmacology 27.1 (Feb. 2007): 35–45.
Glick, Ira D. “Understanding the Results of CATIE in the Context of the Field.” CNS Spectrums 11.7, Supp. 7 (July 2006): 40–47.
Haro, Josep Maria, et al. “Remission and Relapse in the Outpatient Care of Schizophrenia: Three-Year Results from the Schizophrenia Outpatient Health Outcomes Study.” Journal of Clinical Psychopharmacology 26.6 (Dec. 2006): 571–78.
Haupt, Martin, Alfonso Cruz-Jentoft, and Dilip Jeste. “Mortality in Elderly Dementia Patients Treated with Risperidone.” Journal of Clinical Psychopharmacology 26.6 (Dec. 2006): 566–70.
Lieberman, Jeffrey A., et al. “Effectiveness of Antipsychotic Drugs in Patients with Chronic Schizophrenia.” New England Journal of Medicine 353.12 (Sept. 2005): 1209–23.
Luby, Joan, et al. “Risperidone in Preschool Children with Autistic Spectrum Disorders: An Investigation of Safety and Efficacy.” Journal of Child and Adolescent Psychopharmacology 16.5 (Oct. 2006): 575–87.
McCue, Robert E., et al. “Comparative Effectiveness of Second-Generation Antipsychotics and Haloperidol in Acute Schizophrenia.” British Journal of Psychiatry 189 (Nov. 2006): 433–40.
Meltzer, Herbert Y., and William V. Bobo. “Interpreting the Efficacy Findings in the CATIE Study: What Clinicians Should Know.” CNS Spectrums 11.7, Supp. 7 (July 2006): 14–24.
Nasrallah, Henry A. “Metabolic Findings from the CATIE Trial and Their Relation to Tolerability.” CNS Spectrums 11.7, Supp. 7 (July 2006): 32–39.
Pandina, Gahan J., Michael G. Aman, and Robert L. Findling. “Risperidone in the Management of Disruptive Behavior Disorders.” Journal of Child and Adolescent Psychopharmacology 16.4 (Aug. 2006): 379–92.
Savas, Haluk A., et al. “Use of Long-Acting Risperidone in the Treatment of Bipolar Patients.” Journal of Clinical Psychopharmacology 26.5 (Oct. 2006): 530–31.
Schneider, Lon S., et al. “Effectiveness of Atypical Antipsychotic Drugs in Patients with Alzheimer’s Disease.” New England Journal of Medicine 355.15 (Oct. 2006): 1525–38.
Stroup, T. Scott, et al. “Effectiveness of Olanzapine, Quetiapine, Risperidone, and Ziprasidone in Patients with Chronic Schizophrenia Following Discontinuation of a Previous Atypical Antipsychotic.” American Journal of Psychiatry 163.4 (Apr. 2006): 611–22.
Taylor, David M, Corina Young, and Maxine X. Patel. “Prospective 6-Month Follow-Up of Patients Prescribed Risperidone Long-Acting Injection: Factors Predicting Favourable Outcome.” International Journal of Neuropsychopharmacology 9.6 (Dec. 2006): 685–94.
Troost, Pieter W., et al. “Neuropsychological Effects of Risperidone in Children with Pervasive Developmental Disorders: A Blinded Discontinuation Study.” Journal of Child and Adolescent Psychopharmacology16.5 (Oct. 2006): 561–73.
Weiden, Peter J. “EPS Profiles: The Atypical Antipsychotics Are Not All the Same.” Journal of Psychiatric Practice 13.1 (Jan. 2007): 13–24.
Jack Raber, Pharm.D.
Ruth A. Wienclaw, PhD
Ritalin see Methylphenidate
Risperidone
Risperidone
Definition
Risperidone is classified as an atypical antipsychotic drug. It is sold in the United States under the brand name of Risperdal.
Purpose
Risperidone is used for the management of symptoms of psychotic disorders such as schizophrenia .
Description
Risperidone is an atypical antipsychotic agent for two reasons. First, it is chemically unrelated to the older antipsychotic drugs. Second, unlike older antipsychotic drugs that primarily inhibit the actions of dopamine, a chemical in the brain , risperidone may also have some action against another brain chemical, serotonin. The proper level of both dopamine and serotonin are influential in maintaining mental well-being.
An advantage of using risperidone over one of the older antipsychotic drugs is a lower incidence of parkinsonian-like side effects. These side effects may be sufficiently troublesome to cause patients to discontinue treatment for their schizophrenia. For this reason, patients who have had negative experiences with older antipsychotics may benefit from risperidone. Also, some patients who showed little improvement with older antipsychotic drugs respond better to risperidone.
Risperidone is available in 0.25-mg, 0.5-mg, 1-mg, 2-mg, 3-mg, and 4-mg tablets and a solution containing 1 mg of drug in each milliliter of solution.
Recommended dosage
For treating psychotic disorders in adults, the usual starting dose of risperidone is 1 mg twice daily. Dosage is increased gradually until a target dose of 3 mg twice daily is reached. Some patients do just as well with a single daily dose (6 mg once a day, for example). There is little clinical evidence to indicate that increasing the daily dose beyond 8 mg offers additional benefit. However, higher doses may contribute to additional side effects. If the dose needs to be adjusted, the changes should made no more often than once per week.
In older patients (over age 60), starting dosage should not exceed 1 mg daily. Most patients should not take more than 3 mg daily. People with low blood pressure and those who have kidney disease should take a similarly reduced dose.
Precautions
Patients with a history of cardiovascular disease or low blood pressure should take risperidone only after discussing the risks and benefits with their physician, and then with close physician monitoring.
Risperidone has occasionally been associated with seizures . People with a past history of seizures should discuss with their doctor whether risperidone is the right antipsychotic for them to use.
People taking risperidone should avoid operating a motor vehicle or other dangerous machinery until they see how risperidone affects them. Some people have trouble regulating their body temperature while taking risperidone. Patients receiving this drug should be aware of this and avoid extremes in outdoor temperatures.
Side effects
The most common and bothersome side effect associated with risperidone is decreased blood pressure while standing up (known as orthostatic hypotension). This can cause dizziness or fainting. A decrease in blood pressure usually occurs early in therapy, while the proper dose is being established. It is more common in older patients than in younger ones. Usually, this side effect disappears entirely with time. If it continues, the physician may decrease the dose. Meanwhile, people taking risperidone should be aware of this side effect and get up slowly if they have been sitting for an extended time.
The most common nervous system side effects of risperidone include insomnia , agitation, anxiety, and headache. Early in therapy, patients may experience an inability to think clearly or perform certain tasks that require mental alertness. High doses of risperidone can cause unwanted sleepiness in about 40% of patients.
Antipsychotic drugs, including risperidone, can cause side effects that are similar to the symptoms of Parkinson's disease. The patient does not have Parkinson's disease, but may have shaking in muscles at rest, difficulty with voluntary movements, and poor muscle tone. These symptoms normally disappear if the drug is stopped.
The most common gastrointestinal side effects include nausea, vomiting, constipation, and difficulty digesting food.
Up to 10% of patients taking risperidone experience rhinitis (runny nose).
Interactions
There is very little information about how risperidone interacts with other drugs. However, because some patients receiving risperidone experience lowered blood pressure while standing, it is expected that other drugs that lower blood pressure may increase the incidence and severity of this side effect when taken with risperidone.
Resources
BOOKS
American Society of Health-System Pharmacists. AHFS Drug Information 2002. Bethesda: American Society of Health-System Pharmacists, 2002.
O'Brien, Charles P. "Drug Addiction and Drug Abuse." In Goodman & Gillman's The Pharmacological Basis of Therapeutics, edited by Joel G. Hardman, Ph.D. and Lee E. Limbird, Ph.D. Tenth Edition. New York: McGraw-Hill, 2001.
Jack Raber, Pharm.D.