Risperidone is the name given to an atypical neuroleptic. It is used to treat bipolar disorder and schizophrenia.
What is risperidone?
Risperidone is the name given to an atypical neuroleptic. It is used to treat bipolar disorder and schizophrenia. Risperidone also carries the name risperidonum in medicine. This is an atypical neuroleptic that has a strong neuroleptic potency. As an atypical neuroleptic, risperidone is thought to have fewer adverse side effects on the extrapyramidal motor system. However, studies to date have yielded mixed results in this regard. Risperidone was developed between 1988 and 1992 by the German pharmaceutical company Janssen-Cilag, which belongs to the American Johnson and Johnson group. In 1994, the neuroleptic was approved in the United States. After patent protection expired in 2004, risperidone found use as a generic drug.
Pharmacologic action
Physicians attribute psychotic symptoms such as hallucinations or delusions to an increase in the concentration of the neurotransmitter dopamine within the brain. However, antipsychotic drugs can be used to block the dopamine docking sites, which inhibits the effect of the neurotransmitter. However, the first neuroleptics of this type, such as haloperidol or chlorpromazine, had the disadvantage of typical side effects that resembled Parkinson’s disease in their symptoms. The reason for this was the death of nerve cells that secreted dopamine, which in turn caused a dopamine deficiency in the midbrain. The result was symptoms such as slower movements, muscle tremors, muscle rigidity and even immobility. The advantage of risperidone is that its use does not cause these side effects, or they manifest themselves only to a small extent. The positive effect of risperidone comes from blocking the dopamine receptors in the brain. In this way, hallucinations and delusions can be reduced. Furthermore, risperidone also occupies the binding sites of the neurotransmitters adrenaline, noradrenaline and serotonin. This has a positive effect on the patient’s self-control. As a result, they behave less aggressively and can concentrate better. Even severe depression can be counteracted with risperidone. Risperidone is considered to be fifty times more effective than chlorpromazine. After ingestion, the neuroleptic is completely absorbed into the blood via the intestines. After two hours, the maximum concentration is reached there. In the liver, it is metabolized to hydroxyrisperidone, which is equally effective. Both risperidone and its antipsychotic breakdown products pass out of the body via urine at a rate of approximately 50 percent after 24 hours.
Medical application and use
Risperidone is used to treat schizophrenia as well as bipolar disorders. This primarily involves the treatment of psychosis in which the patient suffers from a marked misperception of reality, hallucinations, or delusions. This may be the case in pathological mania or chronic schizophrenia. Psychosis associated with dementia represents another indication of risperidone. Risperidone has the property of reducing aggressive behavior of the patient against his own person or against other people. In addition, the neuroleptic is used as a supportive agent in the social psychiatric treatment of neglected people with pronounced behavioral problems. In the case of mentally less developed children and adolescents, short-term therapy can take place, lasting a maximum of six weeks. In aggressive dementia patients, long-term treatment is considered counterproductive. For example, studies showed higher mortality in affected individuals. Risperidone is taken in tablet form once or twice a day. Food intake has no influence on the administration of the drug. Therapy always starts with a low dose and then gradually increases until the desired effect is achieved. Other dosage forms of risperidone include melting tablets and injections for patients who have difficulty swallowing. A stomach tube is also available for taking the neuroleptic. Because aggressive patients sometimes resist taking the drug, a specially developed risperidone depot injection is often used for them.This drug is injected once every two weeks. Following this, risperidone releases continuously.
Risks and side effects
The most common adverse side effects of risperidone include symptoms similar to Parkinson’s disease. This occurs in about one in ten patients. Other common side effects include headache, insomnia, and drowsiness. In addition, heart palpitations, weight gain, dizziness, listlessness, doze, tremors, breathing problems, cough, nosebleeds, throat and larynx pain, constipation, diarrhea, abdominal pain, nausea, vomiting, back pain, limb pain, fever, respiratory infections, skin rashes, edema, or anxiety are possible side effects. Parkinson’s disease patients and young people are often at risk of malignant neuroleptic syndrome, which is associated with high fever, muscle rigidity, circulatory collapse, and clouded consciousness. In such cases, risperidone therapy should be discontinued immediately. If the patient is hypersensitive to risperidone, the drug must not be administered. The same applies to an increased concentration of the hormone prolactin without drug influence. Thorough consideration by the physician for risperidone administration is necessary in cases of renal dysfunction, Parkinson’s disease, epilepsies, cardiac arrhythmias, liver function limitations, low blood pressure, tumors, and dementia. The use of risperidone during pregnancy and lactation is not recommended. Thus, the harmlessness of the active ingredient could not be proven for either the mother or the child. Interactions due to the simultaneous administration of risperidone and other drugs are also conceivable. For example, the effect of tetracyclic or tricyclic antidepressants or beta blockers is increased. If risperidone and dopamine receptor agonists are taken at the same time to treat PD, this leads to an attenuation of the agonist effect.
