LYCOS RETRIEVER 
Risperidone
built 622 days ago
Risperidone long-acting injection is the first and only long-acting, atypical antipsychotic to be approved by the U.S. Food and Drug Administration and now is approved in more than 70 countries worldwide. The treatment uses Alkermes proprietary Medisorb(R) technology to deliver and maintain therapeutic medication levels in the body through just one injection every two weeks. Janssen markets Risperidone long-acting injection in the United States. The formulation is manufactured by Alkermes, Inc. (Nasdaq: ALKS). Available in 12.5 mg, 25 mg, 37.5 mg and 50 mg dose units, it is approved for the treatment of schizophrenia. For more information about RISPERDAL CONSTA, visit http://www.risperdalconsta.com.
Source:
Risperidone is an antipsychotic agent belonging to the benzisoxazole derivatives class. The mechanism of action is unknown; ... antipsychotic activity may be mediated through a combination of dopamine (D2) and serotonic (5HT2) antagonism. Risperidone is well absorbed by the gut. It is extensively metabolized in the liver to a major active metabolite, 9-hydroxyrisperidone, which appears approximately equieffective with risperidone with respect to receptor binding activity. Consequently, the clinical effect of the drug likely results from the combined concentrations of risperidone and 9-OH-risperidone. The pharmacokinetics for the sum of the two, after single and multiple doses, were similar in both rapid and slow metabolizers, with an overall mean elimination half-life of about 20 hours.
Source:
Risperidone and other atypical antipsychotics appear to promote a higher quality of life compared to conventional antipsychotics. Physical well being, social life and everyday life have ... been rated higher in a comparative study using risperidone (Franz et al, 1997). In one evaluation, compared to haloperidol, a conventional antipsychotic, risperidone-treated patients obtained more than twice as many quality-adjusted years as haloperidol patients and in addition risperidone was found to be cost-effective, (Chouinard & Albright, 1997). A U.S. evaluation of costs, including indirect ones came up with figures for treatment with haloperidol and risperidone (Keks, 1997). A robust decision-analytic model of schizophrenia suggested that the overall 1997 cost of treating a patient with risperidone would be $11,772.00 per year compared with $13,622.00 per year for haloperidol and that the cost per response is even more favourable for risperidone; $14,599.00 versus $23,040.00.Guidelines issued by the Australian Pharmaceutical Benefits Advisory Committee have been used to construct a model for comparing the cost-effectiveness of risperidone and haloperidol over a 2-year period in patients with chronic schizophrenia (Davies et al, 1998). Cost-effectiveness was determined by using decision-analytic modelling.
Source:
Risperidone displays a novel mechanism of antagonism of the h5-HT7 receptor. Pretreatment of the cells with 5 or 20 nM risperidone, followed by removal of the drug from the media, renders the 5-HT7 receptors unresponsive to 10 µM 5-HT for at least 24 h. Thus, risperidone seems to be producing a rapid, long-lasting inactivation of the h5-HT7 receptor. Whole-cell radioligand binding studies indicate that risperidone interacts in an irreversible or pseudo-irreversible manner with the h5-HT7 receptor... producing the inactivation. Internalization of the h5-HT7 receptor was not detected by monitoring green fluorescent protein-labeled fluorescent forms of the h5-HT7 receptor exposed to 20 nM risperidone. Ten other antagonists were tested for h5-HT7-inactivating properties, and only 9-OH-risperidone and methiothepin were found to demonstrate the same anomalous properties as risperidone. These results indicate that the h5-HT7 receptor may possess unique structural features that allow certain drugs to induce a conformation resulting in an irreversible interaction in the intact membrane environment.
Source:
Risperidone is metabolized by cytochrome P450IID6 enzyme. Both the parent drug and main metabolite are preferentially distributed to the frontal cortex and striatum in the brain, where half-lives are longer than in the plasma. Excretion is mainly renal, with a small amount excreted in the feces. About 90% of an oral dose is eliminated, with a half-life of about 3 hours; half-life of the metabolite is about 24 hours. Renal disease reduces total clearance and prolongs elimination half-life. Reduced dosage levels are indicated in patients with hepatic or renal disease.
Source:
DOSING: Risperidone usually is begun as two small doses each day. The doses often are increased every few days or each week until the optimal dose is found. Patients who are elderly or have kidney disease may need lower doses since the kidneys, which are partially responsible for removing risperidone from the blood, remove risperidone more slowly, and this can lead to toxic levels of risperidone in the blood. Similarly, patients with liver disease may need lower doses since the liver ... is partially responsible for removing risperidone.
Source:
MORE ABOUT
Risperidone