Risperidone (Risperdal)

Risperidone is a second generation neuroleptic, also known as atypical antipsychotics. Its most common brand name is Risperdal, but it also comes in a long-acting injectable form under the brand name Risperdal Consta®.

What it’s used to treat

Although initially approved by the FDA in 1993 for the treatment of adult schizophrenia, the FDA has since approved it for other age groups as well as disorders. In 2003 it was approved to treat acute manic episodes for adult individuals with bipolar I disorder.

Even though many prescribers had used it to treat adolescents with schizophrenia for years, it wasn’t officially approved for the treatment of schizophrenic teens until 2007 1. That same year it was also approved to treat symptoms of mania in adolescents and children between the ages of 10 and 17 diagnosed with bipolar disorder 1.

Risperdal Consta, the long-acting injection version of risperidone, was first approved for the treatment of schizophrenic individuals in 2003 2, and later approved for managing bipolar disorder in 2009 3. When treating bipolar disorder, it may be used alone or in combination with valproate or lithium, two drugs often used to treat bipolar disorder.

Risperidone is the only drug of its kind approved by the FDA to treat symptoms of irritability in autistic youth between 5 and 16 years of age 4. It is also often used “off-label” to treat individuals with Tourette’s Syndrome, as well as anxiety, even though it is not officially approved for either of these disorders.

How it works

Risperidone works by bringing two neurotransmitters in the brain back into balance. The two brain chemicals it impacts are serotonin and dopamine. While the exact mechanism in which it does this is not fully understood, it has been a very effective treatment for many people with schizophrenia as well as bipolar disorder. It is, however, believed to either reduce or even block the effects of these brain chemicals, which are likely elevated in individuals with these disorders. The older antipsychotic medications appear to impact dopamine only.

For many people, risperidone can act very quickly in the reduction of symptoms. Full effects may not be experienced for several weeks in some patients.

How it’s administered

Risperidone is available in several different strengths to be taken orally as a pill or a liquid. Under the brand name Risperdal Consta, it is available as a long-acting alternative which is administered via injection.

Potential Side Effects

The most typical side effects of risperidone include:

  • Drowsiness
  • Increase in appetite and weight gain
  • Tiredness
  • Colds and other respiratory infections
  • Difficulties sleeping
  • Agitation
  • Increase in saliva production
  • Feelings of anxiety
  • Indigestion, stomach pain, and / or nausea
  • Headaches
  • Light-headedness
  • Decreased libido and / or sexual performance
  • Problems urinating
  • Dry mouth
  • Rash

Other more serious side effects may include (but are not limited to) fever, confusion, rapid or irregular heartbeat, difficulties breathing and seizures.

Risperidone may also cause tardive dyskinesia and neuroleptic malignant syndrome.

Tardive dyskinesia (TD). TD symptoms involve involuntary, random and uncontrollable movements, such as lip smacking, odd tongue or jaw movements, blinking, grimacing, and movements involving the limbs, fingers, toes, upper body or hips. TD symptoms can be permanent for some patients, but has been known to be temporary for others.

Neuroleptic malignant syndrome (NMS) is a potentially life-threatening side effect of haldol. Some of the symptoms include muscle stiffness, changes in one’s mental state, fluctuations in blood pressure or heartbeat, sudden renal failure, tremors, difficulty breathing, dehydration, rapid heartbeat, and extremely high temperature.


While the list of precautions with Risperidone, as well as most medications, is very lengthy, several are noted here:

Because Risperdal M-Tab has phenylalanine in it, individuals with phenylketonuria should not take it.

Risperidone may cause an increase in blood sugar, so if you have diabetes or a family history of diabetes, alert your doctor before taking risperidone.

As with almost all antipsychotics, risperidone may increase the risk of death in elderly individuals with dementia.

If you are at risk for or have a history of seizures, be sure to tell your doctor as this is a potential side effect of risperidone.

If you are pregnant, considering getting pregnant, or nursing, tell your doctor before taking risperidone. It is not recommended for women who are nursing.

written by Dr. Cheryl Lane, PsyD


  1. "FDA Issues Approvable Letter for Risperdal to Treat Adolescents with Schizophrenia and Children and Adolescents with Bipolar Mania," June 2007
  2. "FDA Approves Risperdal Consta," Oct 2003
  3. "Johnson & Johnson Receives FDA Approval for RISPERDAL CONSTADrug Discovery & Development," May 2009
  4. "FDA Approves RISPERDAL(R) For Treatment Of Irritability Associated With Autistic Disorder," Medical News Today, Oct. 2006