Resources - Medications
Risperdal (risperidone)
What is Risperdal?
Risperdal (risperidone), released in 1994, is one of the atypical antipsychotic medications used to treat schizophrenia and psychotic disorders. The drug helps manage schizophrenia's positive symptoms (e.g., visual and auditory hallucinations, delusions, and thought disturbances) and may also help treat the illness' negative symptoms (e.g., social withdrawal, apathy, lack of motivation, and inability to experience pleasure). It may also be useful in treating acute mania and severe depression in combination with antidepressant medications. Risperdal's side effects are usually relatively minor, and blood monitoring is not necessary.
How is Risperdal different from other antipsychotic medications?
Conventional antipsychotics such as Haldol, Stelazine, and Prolixin have treated positive symptoms in many patients for several years. However, these drugs do not satisfactorily affect the negative symptoms, and they often cause uncomfortable or intolerable side effects. Risperdal is as effective as the conventional medications in treating positive symptoms. Risperdal also offers the advantages of helping treat negative symptoms and causing fewer extrapyramidal side effects (EPS) such as restlessness, muscle rigidity, and tremor when taken at the manufacturer's recommended dose of 6 mg per day or less.
How does Risperdal work?
Risperdal, like some other atypical antipsychotics, is designed as a serotonin/dopamine antagonist. While its exact mechanism of action is not yet understood, Risperdal seems to block the action of serotonin and dopamine, two neurotransmitter chemicals in the brain. Conventional antipsychotics seem to primarily affect only dopamine.
How quickly does Risperdal relieve symptoms of schizophrenia?
Improvement of symptoms may be noticed in some patients relatively quickly. Some adjustments may be necessary to reach the optimal dose for each patient. It is normally advisable to give the medication a trial period of at least four to six weeks at the optimal dose before evaluating its effectiveness, although experience with Clozaril suggests that improvements may take months to fully emerge. When first released, the recommended dose for Risperdal was 6 mg/day. It is now known that lower doses (3 or 4 mg/day) are often effective with lower risk for side effects.
What are the side effects of Risperdal?
When taken at the manufacturer's recommended dose of 6 mg/day or less. Risperdal has been observed to cause no higher rate of significant side effects than the rate observed with placebo. These side effects include extrapyramidal symptoms (muscle stiffness, tremors, and body shakes). At higher doses, extrapyramidal side effects often increase. Cogentin (benztropine) can be prescribed to reduce or eliminate stiffness and tremors, but its use beyond three months should be reevaluated.
More significant possible side effects, affecting some patients but not all, include low blood pressure; dizziness, especially when standing up suddenly; heart palpitations; sleepiness; constipation; weight gain; sexual dysfunction; and fatigue. Some of these problems can be minimized by following recommended guidelines for dosage at the beginning of treatment (gradual increase of dose over a period of several weeks). Patients who already have low blood pressure, have kidney or liver impairment, are elderly, or are in a weakened condition may require close monitoring and even more gradual dose adjustment.
Does Risperdal cause tardive dyskinesia?
Tardive dyskinesia (TD), a disfiguring side effect that occurs in some patients taking antipsychotic drugs, may not be a major risk associated with Risperdal use, although it may take years before researchers can fully assess the risk. It is prudent to minimize the risk by using the lowest dose necessary to relieve psychotic symptoms. Should symptoms of TD develop, such as grimacing, sucking and smacking of lips, and other spasmodic movements, discontinuation of Risperdal should be considered.
What else should be kept in mind when taking Risperdal?
Risperdal can be taken before, during, or after meals. Patients should be cautious about operating hazardous machinery, including driving, until they are certain they are not adversely affected. Women should let their doctor know if they become pregnant or intend to become pregnant. Breast feeding is not recommended while taking Risperdal. Because some medications can affect the effectiveness of Risperdal when taken at the same time, patients should be sure their doctor is aware of all medications they are taking.
Reviewed by Jack Gorman, M.D., Chair NAMI Scientific Council, Sept 2002
Information from NAMI's Website (http://www.nami.org)
