Medications and Drugs
Pharmacy Author: Annette O. Gbemudu PharmD, MBA
Medical and Pharmacy Editor: Jay W. Marks, MD
GENERIC NAME: risperidone
BRAND NAME: Risperdal, Risperdal Consta
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. Risperdal
Consta is an injectable, long-acting form of risperidone.
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,
Risperdal. No, Risperdal Consta
PREPARATIONS: Tablets: 0.25,
0.5, 1, 2, 3, and 4 mg. Oral solution: 1 mg/mL. Orally disintegrating tablets: 0.5, 1, 2, 3, and
4 mg. Powder for injection: 12.5, 25, 37.5, and 50 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. The recommended dose of Risperdal Consta is 25 mg injected into
the deltoid or gluteal muscle every two weeks. Patients who have never received risperidone
are started on oral risperidone in order to evaluate tolerability. Patients then may be
transitioned to Risperdal Consta if oral risperidone is tolerated
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.
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.
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