Risperidone: Everything You Need to Know

Risperidone is used to treat the symptoms of various complex conditions, such as schizophrenia and autism. Its dosage depends on the patient and the disease to be treated.

Written and verified by el biólogo Samuel Antonio Sánchez Amador.

Last update: 03 September, 2021

Risperidone is a second-generation chemical compound used to treat schizophrenia, bipolar disorder, aggression, and the irritability associated with autism. It can be taken orally or as an intramuscular injection, although in its injectable version it has long-term effects of up to 2 weeks.

This drug works by blocking the receptors of some substances, such as dopamine and serotonin. It should be noted that the term risperidone refers to the active substance, but it’s usually marketed under different trade names. Some of them are Arketin ®, Calmapride ®, Diaforin ®, Rispemylan Flas ® and Risperdal ®.

The study of risperidone began in the 1980s and the Food and Drug Administration (FDA) approved it in 1993. In 2018, this drug was number 159 in terms of prescriptions in the United States, with more than 3 million annual prescriptions.

What is risperidone used for?

Risperidone is an antipsychotic chemical compound. As such, it fundamentally modifies the brain, in order to reduce symptoms and treat manic episodes in patients with bipolar disorder.

First, it should be noted that all antipsychotics have a certain antagonistic relationship with the D2 family receptors. These are dopamine (dopamine) receptors that are found prominently in the central nervous system (CNS) of vertebrates.

As indicated in the Journal of Mental Disorders and Treatment, an abnormality in the signaling of the dopaminergic pathways may explain some aspects of certain severe neuropsychiatric disorders. By acting as antagonists of dopamine receptors, first-generation antipsychotics seek to reduce the symptoms of these psychological diseases.

However, we should highlight that risperidone, in addition to blocking D2 receptors, also inhibits the action of serotonin receptors, such as types 5HT1A and 5HT2A. Being a second-generation antipsychotic, the following physiological mechanisms are attributed to it:

• Inhibition of serotonin and norepinephrine reuptake: Thanks to this mechanism, antidepressant properties are attributed to the drug.
• Blocking D2 receptors: By blocking these receptors in the prefrontal cortex and the nucleus accumbens, risperidone helps alleviate certain psychiatric symptoms.

FDA approved uses

The Food and Drug Administration (FDA) has approved the use of risperidone in all its forms for the following pathologies:

• Schizophrenia in adults and children 13 years of age and older.
• Type 1 bipolar disorder: to alleviate acute or mixed manic episodes in children 10 years of age and older.
• Irritability associated with autism: in child patients 5 years of age and older.

Long-acting risperidone injections have been approved as monotherapy for the long-term management of schizophrenia and bipolar disorder in adults. On the other hand, the approach to aggressiveness associated with dementia or behavior problems is established in the short term, with a maximum duration of 6 weeks.

Uses not approved by the FDA

In many cases, professionals prescribe off-label drugs in order to alleviate certain symptoms. This doesn’t mean that they’re dangerous or negative, but rather that more research is required to test their effectiveness.

Risperidone has also been used historically for borderline personality disorder, delusions, depression, certain brain damage, and Tourette syndrome, among other conditions. Doctors have also used it in cases of conflictive behavior in patients with an autism spectrum disorder.

How is risperidone administered?

Risperidone comes in injectable form and as a tablet to take orally. In the following lines, we’re going to focus on the last variant, as it’s the one that must be managed from home.

To do this, we’re going to use the Risperidone Apotex 2 milligrams ® leaflet as a reference, which deals with the tablets that contain 2 milligrams of the active ingredient per unit.

Administration for the treatment of schizophrenia

In adults, the starting dose is 2 milligrams a day, but, on the second day, it can be increased to 4 milligrams. Most patients take 4 to 6 milligrams a day divided into 1 or 2 doses, depending on the doctor’s instructions. The prescription can be modified based on individual responses.

In elderly patients, a dose of 0.5 milligrams is started twice a day. Then it can be increased to 1-2 milligrams twice a day, but the general dose is lower than in the previous case. The prescription isn’t suitable for children and adolescents, as this brand doesn’t recommend its use in children under 18 years of age.

Administration for the treatment of mania

For adults, start with a dose of 2 milligrams a day in a single dose. This can be increased gradually, although it should be noted that most patients do well in the pharmacological range of 1 to 6 milligrams daily.

For older patients, the starting dose is 0.5 milligrams twice a day, although it’s usually increased over time to 1-2 milligrams, also twice a day. This isn’t recommended for use in children and adolescents under 18 years of age either.

Administration for aggressiveness in people with Alzheimer’s dementia

In these cases, you should begin in all cases with 0.25 milligrams, twice a day. It can be increased to 0.5-1 milligrams twice a day, depending on the individual response. The duration shouldn’t exceed 6 weeks.

Administration for conduct disorders in children and adolescents

In this case, the dosage is more complicated, as it depends on the child’s weight. We can summarize it in the following list:

• If the child weighs less than 50 kilos: always start with 0.25 milligrams a day in a single dose. It can be increased to 0.75 milligrams daily.
• If the child weighs more than 50 kilos: start with 0.5 milligrams a day in a single dose and the dose can be increased to 1.5 milligrams daily.
• In children under 5 years of age: The use of risperidone is not considered.

Who shouldn’t take risperidone?

As indicated by the Statpearls portal, one must refrain from prescribing any of the aforementioned trademarks to any patient who has had previous hypersensitivity reactions to risperidone or paliperidone (a metabolite of this compound). Neither is it recommended in people with persistent hallucinogenic perception disorder, as a worsening of symptoms has been reported.

Risperidone and pregnancy

There are insufficient data to support the safety of risperidone in pregnant women. However, according to Vademecum, newborns exposed to antipsychotics during the third trimester of pregnancy are in danger of suffering adverse reactions with extrapyramidal symptoms and withdrawal.

Lactation

In animal studies, risperidone has been shown to be excreted in milk. It’s also released in human breast milk, but no ill effects on babies have been found.

What are the possible side effects?

Like all medicines, risperidone can cause certain short-term and long-term problems. Here are the side effects:

• Very common side effects (more than 1 in 10 people): Parkinsonism with musculoskeletal stiffness, drooling, pain when bending the limbs, locomotor slowness, lack of expression, muscle tightness, and much more.
• Common (affects up to 1 in 10 people): Fatigue, tiredness, inability to stay calm, irritability, vomiting, diarrhea, anxiety, constipation, nausea, increased appetite, shortness of breath, rapid heartbeat, chest pain.
• Uncommon (up to 1 in 100 people): Fecal incontinence, very hard stools, skin lesions, fainting, gait disturbances, lack of response to stimuli, painful hypersensitivity to light, erectile dysfunction.
• Rare (up to 1 in 1000 people): Intestinal obstruction, dandruff, glaucoma, decreased visual acuity, muscle fiber breakage, coma, movement disorders.
• Very rare (up to 1 in 10,000 people): Complications with uncontrolled diabetes.

What happens if I miss a dose?

If you miss a dose, take it as soon as possible. However, if you’re getting close to the next dose, you’d better skip the one you missed and continue with the treatment as normal. If you miss two dosis in a row, contact your doctor. Never take two or more pills to make up for missed doses.

What should I do in case of an overdose?

Studies have shown that the effects of a risperidone overdose are manifested by lethargy, spasms, dystonia, hypotension, and tachycardia. All risperidone overdoses require admission of the patient to emergencies.

However, most patients recover within 24 hours of treatment and almost all of them are asymptomatic within 72 hours. If you think you’ve taken too much risperidone, don’t hesitate to go to the emergency room with the medicine box in hand.

How to store and dispose of this medicine?

This medicine doesn’t require specific storage in its oral form. You just have to be careful to keep it out of the reach of children. On the other hand, the drug shouldn’t be thrown away or put down the toilet.

Contact the relevant health authorities and find out about the procedure to be carried out to dispose of this medication.

Risperidone for official and off label uses

Risperidone is a second-generation antipsychotic drug used to treat schizophrenia, bipolar disorder, aggression, and irritability associated with autism. Although these are its official uses, it’s also used off-label in the short term to address behavioral problems in young people and adolescents.

Ultimately, we must remember that the disorders mentioned here are extremely complex and their treatment requires a multidisciplinary approach. Beyond the pharmacological field, ongoing psychological care and long-term patient monitoring is also necessary.