Pharmacy Author: Annette O. Gbemudu PharmD, MBA
Medical and Pharmacy Editor: Jay W. Marks, MD
GENERIC NAME: risperidone
BRAND NAME: Risperdal
DRUG CLASS AND MECHANISM: Risperidone is an atypical antipsychotic
drug that is used for treating schizophrenia,
bipolar mania and autism. Other
atypical antipsychotic drugs include Olanzapine (Zyprexa), Quetiapine
(Seroquel), Ziprasidone (Geodon), Aripiprazole (Abilify) and
paliperidone (Invega).
Atypical antipsychotics differ from typical antipsychotics due to the lesser
degree of extrapyramidal (movement) side effects and constipation.
The exact
mechanism of action of risperidone is not known, but, like other
anti-psychotics, it is believed that risperidone affects the way the brain works
by interfering with communication among the brain's nerves. Nerves communicate
with each other by making and releasing chemicals called neurotransmitters. The
neurotransmitters travel to other nearby nerves where they attach to receptors
on the nerves. The attachment of the neurotransmitters either stimulates or
inhibits the function of the nearby nerves. Risperidone blocks several of the
receptors on nerves including dopamine type 2, serotonin type 2, and alpha 2
adrenergic receptors. It is believed that many psychotic illnesses are caused by
abnormal communication among nerves in the brain and that by altering
communication through neurotransmitters, risperidone can alter the psychotic
state. Risperidone was approved by the FDA in December, 1993.
PRESCRIPTION: Yes.
GENERIC AVAILABLE: Yes.
PREPARATIONS: Tablets: 0.25, 0.5, 1, 2, 3, and 4mg. Oral solution: 1
mg/mL. Orally disintegrating tablets: 0.5, 1, 2, 3, and 4 mg.
STORAGE: Tablets should be kept at room temperature, 15-25 C (59-77 F).
PRESCRIBED FOR: Risperidone is used to treat schizophrenia, bipolar
mania [as a sole therapy or combination therapy with
lithium (Eskalith, Lithobid) or
valproate (Depakene, Depacon) and
for the treatment of irritability associated with autistic disorder in children
and adolescents. Clinical studies involving small numbers of patients have shown
some benefit in using risperidone for stuttering and
Tourette syndrome (non
FDA-approved uses). Another non-FDA approved use of risperidone is for
obsessive-compulsive disorders.
DOSING: Risperidone can be administered once or twice daily. Initial
dosing is generally 2 mg/day. Dose increases can occur in increments of 1-2
mg/day, as tolerated, to a recommended dose of 4-8 mg/day. In children,
risperidone should be initiated at 0.5 mg once daily, and can be increased in
increments of 0.5 or 1 mg/day, as tolerated, to a recommended dose of 2.5
mg/day. Risperidone can be given with or without meals.
DRUG INTERACTIONS: Risperidone may interfere with elimination by the
kidneys of clozapine (Clozaril), a different type of antipsychotic medication,
causing increased levels of clozapine in the blood. This could increase the risk
of side effects with clozapine.
Serotonin reuptake inhibitors such as paroxetine (Paxil), Sertraline
(Zoloft), and fluoxetine (Prozac) when taken with risperidone causes the
metabolism (breakdown) of risperidone by the liver to be inhibited, which in
turn causes elevated blood levels of risperidone, and may increase the risk of
adverse reactions.
Antifungal drugs such as fluconazole (Diflucan), itraconazole (Sporanox), and
ketoconazole (Nizoral) when taken with risperidone cause the metabolism
(breakdown) of risperidone by the liver to be inhibited, which in turn causes
elevated blood levels and may increase the risk of adverse reactions.
PREGNANCY: There are no adequate studies of risperidone in pregnant
women. Some unwanted effects have been reported in animal studies. Risperidone
can be used in pregnancy if the physician feels that the benefits outweigh the
potential but unknown risks.
NURSING MOTHERS: Risperidone is excreted in human breast milk. Women
receiving risperidone should not breastfeed.
SIDE EFFECTS: The most commonly-noted side effects associated with
risperidone are extrapyramidal effects (sudden, often jerky, involuntary motions
of the head, neck, arms, body, or eyes), dizziness, hyperactivity, tiredness,
abdominal pain, fatigue, fever and nausea. Risperidone may cause a condition
called orthostatic hypotension
during the early phase of treatment (the first week or two). Patients who
develop orthostatic hypotension have a drop in their blood pressure when they
rise from a lying position and may become dizzy or even lose consciousness.
Studies involving risperidone suggest an increased risk of
hyperglycemia-related adverse reactions as seen in diabetes. Although there is
no clear link between risperidone and diabetes, patients should be tested during
treatment for elevated blood sugars. Additionally, persons with risk factors for
diabetes, including obesity or a family history of diabetes, should have their
fasting levels of blood sugar tested before starting treatment and periodically
throughout treatment to detect the onset of diabetes. Any patient developing
symptoms that suggest diabetes during treatment should be tested for diabetes.
Last Editorial Review: 3/27/2009
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
- Schizophrenia - Get information on schizophrenia symptoms (delusions, hallucinations), causes (genetics), diagnosis, treatment of schizophrenics (antipsychotic drugs) and types (paranoid).
- Bipolar Disorder (Mania) - Read about bipolar disorder (BD or manic-depressive illness), a brain disorder that causes dramatic mood swings (highs and lows) and affects a person's energy levels and ability to function. These highs and lows are episodes of mania and depression. The mania symptoms of manic depression include increased energy, extreme irritability, spending sprees, and increased sex drive. Depression symptoms include feelings of hopelessness and worthlessness, decreased energy, thoughts of death or suicide, and chronic pain. Long-term preventive treatment combining medication and psychosocial treatment is recommended.
- Obsessive Compulsive Disorder (OCD) - Obsessive compulsive disorder (OCD) is an anxiety disorder that causes a person to suffer repeated obsessions and compulsions. Learn symptoms, diagnosis and treatment.
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