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Risperidone (Belivon®, Rispen®, Risperdal®) is an atypical antipsychotic medication. It is most often used to treat delusional psychosis.
Side effects
Risperidone can potentially cause tardive dyskinesia. Common side effects include: nausea, anxiety, dizziness, insomnia, low blood pressure, muscle-stiffness/pain, sedation, tremors, and weight-gain.
Pharmacology
Risperidone is a very strong dopamine blocker (antagonist); i.e., it inhibits functioning of dopamine receptors. It reaches peak plasma levels quickly regardless of whether it is administered as a liquid or pills. The strong dopamine-blocking reaction is known to make some people feel nauseated if they do things that normally trigger the dopamine response, such as eat a pleasing meal or experience orgasm. Risperidone is metabolised fairly quickly so this potential for nausea subsides usually in two to three hours.
Current forms
Risperidone is available in the form of ordinary tablets, fast-dissolving tablets, and solution taken orally, and in the form of a long-lasting injection, known as Risperdal Consta. The latter is especially important, due to the high percentage of mentally ill persons (especially with schizophrenia) who are unable or unwilling to take daily medication orally because of their impaired ability to distinguish between reality and fantasy.
Risperdal is manufactured by Johnson & Johnson (NYSE: JNJ), which also makes Risperdal Consta in conjunction with Alkermes, Inc.
Chemistry
Risperidone is 3-[2-[4-(6-fluoro-1,2-benzisoxazol-3-yl)-1-piperidinyl]ethyl]-6,7,8,9-tetrahydro-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one, C23H27FN4O2.
Safety risks
In 2004, the Committee for the Safety of Medicines (CSM) in the UK issued a warning that risperidone and another atypical antipsychotic, olanzapine, should not be given to elderly patients with dementia, because of an increased risk of stroke.
On July 24, 2004, Janssen Pharmaceutica Products LP, the subsidiary of Johnson & Johnson that manufactures Risperdal, admitted that it had minimized Risperdal's risks in its promotional material, risks that included strokes, diabetes and other potentially fatal complications. This disclosure followed a finding by the Food and Drug Administration that Janssen was continuing to make misleading claims that the medication was safer in treating mental illness than similar drugs. The Miami Herald also reported that several boys in Florida developed lactating breasts after taking Risperdal.
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