Risperdal is the first in its class, a new kind of medicine prescribed to treat psychotic disorders.
Clinical studies show that it is effective against the symptoms of schizophrenia such as hallucinations, suspiciousness and disorganized thought.
It also appears to be helpful against other schizophrenic symptoms, including apathy and social withdrawal, that don't respond well to other medications.
Risperdal may be effective for certain patients who haven't responded well to other antipsychotic drugs.
Some experts believe that Risperdal is better than the older and more conventional schizophrenia drug Haldol, and it has a different side-effect profile.
Side Effects and Interactions
Some people starting on Risperdal may find that they feel dizzy or faint if they stand up suddenly. They should take care to avoid falling when they first get up.
Risperdal may cause anxiety, drowsiness, dizziness, constipation, nausea, indigestion, runny nose, rash, rapid heart beat and uncontrollable muscle movements,
Other adverse reactions to be alert for include sleeping longer and dreaming more, visual problems, sensitivity to sunlight leading to sunburn, fatigue, weight gain, diarrhea, constipation, sexual difficulties, difficult urination, heavy menstrual periods, dry vagina and reduced salivation.
Report any symptoms to your physician promptly.
Risperdal may interact with other medications, but most of the potential interactions have not yet been carefully studied.
Alcohol should be avoided by patients taking this drug.
Blood pressure medicines may increase the trouble with feeling faint upon standing up (orthostatic hypotension).
Risperdal may counteract the benefits of the Parkinson's disease drug levodopa.
The antiseizure drug Tegretol may speed removal of Risperdal from the body, possibly reducing its concentration below the desired level.
The antischizophrenic medicine Clozaril can reduce the body's ability to eliminate Risperdal and may lead to increased blood levels.
Many medications processed by the same liver enzyme as Risperdal have a potential for interaction, but the medicine is still so new that there are few if any reports as of this writing.
Check with your doctor and pharmacist to make sure Risperdal is safe in combination with any other drugs you take.
Because Risperdal is metabolized through the liver and kidneys, people with kidney disease or liver problems need to have their dose of Risperdal adjusted carefully.
Older people, who often have reduced kidney or liver function, may also require lower doses.
Since Risperdal, like other drugs that affect the nervous system, might slow reflexes or impair judgment, people taking it should be advised not to drive or operate dangerous equipment unless they can determine that they are unimpaired.
Antipsychotic drugs may in some cases trigger a life-threatening reaction in which body temperature rises, muscles become rigid, heart rhythm and blood pressure changes and the person loses consciousness. This is a medical emergency, and a person on any schizophrenia medicine who develops some of these symptoms should be treated immediately.
Long-term use of conventional antipsychotic drugs can lead to the development of involuntary repetitive movements such as jerks, tics, twitches, chewing or tongue-thrusting. Called tardive dyskinesia, this side effect is among the most unpleasant drawbacks of chronic treatment for schizophrenia.
It is hoped that holding Risperdal doses to 6 mg daily or less will reduce the risk of tardive dyskinesia. Because the drug is so new, however, long-term experience with it is limited.
Taking the Medicine
Risperdal should be taken twice a day and may be taken with or without meals.