Risperidone dosage, forms, and strengths

Risperdal (risperidone) is a member of the second-generation antipsychotic class of medications (also called atypical antipsychotics). It is indicated for the treatment of schizophrenia, mania related to bipolar I disorder, and irritability associated with autistic disorder. Used off-label or without a FDA indication, Risperdal is sometimes prescribed for Tourette syndrome, delusional disorder, treatment-resistant depression, Huntington disease-associated chorea, obsessive compulsive disorder, and agitation associated with dementia and delirium. Risperidone seems to exert its effects by altering brain chemicals such as dopamine. Common forms of Risperdal include regular and orally disintegrating tablets with a dose range from 0.25 mg to 4 mg, as well as a 1 mg/1 mL oral solution and injectable forms.

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Risperidone forms and strengths

• Risperdal tablet: 0.25 mg, 0.5 mg, 1 mg, 2 mg, 3 mg, 4 mg

• Risperdal tablet disintegrated: 0.25 mg, 0.5 mg, 1 mg, 2 mg, 3 mg, 4 mg

• Risperdal oral solution: 1 mg/1 mL

• Risperdal consta injection: 12.5 mg, 25 mg, 37.5 mg, 50 mg

• Perseris prefilled injection syringe: 90 mg, 120 mg

Risperidone dosage for adults

Oral Risperdal and Risperdal Consta injections are indicated for adults with schizophrenia and mania related to bipolar I disorder. Perseris injection indications are limited to schizophrenia.

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Risperidone dosage restrictions

Patients with liver or kidney dysfunction may be prescribed risperidone in lower doses.

• Renally impaired patients (creatinine clearance < 30 mL/min): Starting dose of 0.5 mg twice daily and increased to 1.5 mg twice daily if needed. Further potential increases no more often than weekly increments.

• Hepatically impaired patients (Child-Pugh Class C): Starting dose of 0.5 mg twice daily and increased to 1.5 mg twice daily if needed. Further potential increases no more often than weekly.

• Patients older than 65 with schizophrenia: Starting low dose of 0.25 mg per day with a slow increase if needed to a usual dose of 2 mg per day.

Seniors taking risperidone are at a heightened risk of adverse effects. Orthostatic hypotension, which is a short-term drop in blood pressure precipitated by sitting or standing up, is a concern as it may cause fainting or falling. An increased risk of death has been noted in individuals with dementia who are taking risperidone for psychosis.

Risperidone dosage for pets

There is no FDA-approved use of risperidone in pets. Some trial use has occurred for aggression.

How to take risperidone

Risperidone has the potential for profound benefit but also significant adverse reactions. This makes careful dosing and adherence to instructions paramount. Risperidone can be taken with or without food, but there are certain nuances of taking risperidone that can make a difference.

• Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.

• Measure the oral liquid medicine with a marked measuring spoon, oral syringe, or medicine cup. You may mix your dose of risperidone with water, coffee, low-fat milk, or orange juice. Do not mix it with cola or tea.

• Make sure your hands are dry before you handle the disintegrating tablet. Peel back the foil from the blister pack, then remove the tablet. Do not push the tablet through the foil. Place the tablet in your mouth. After it has melted, swallow or take a drink of water.

• Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Do not freeze the oral liquid.

Risperidone dosage FAQs

Risperdal vs. Risperdal Consta vs. Perseris: What’s the difference?

Risperdal is oral risperidone that is taken once or twice a day. The injectable forms for home use provide an option for longer interval dosing, which makes compliance easier. Risperdal Consta is an injection in the muscle every two weeks, and Perseris is an injection under the skin once a month.

How long does it take risperidone to work?

Effects might be noted in the first few days, but the full effect of risperidone may take a few weeks. Long-acting injectable forms may take longer to produce results.

How long does risperidone stay in your system?

The mean half-life of risperidone is 20 hours, meaning that it takes that long for the concentration in the body to go down by 50%. In other words, it takes about four days for the body to eliminate 97% of Risperdal after one stops taking it.

How long can you take risperidone?

Risperidone can be taken indefinitely if needed. In some instances, cautious medication discontinuation can be done under the direction of a healthcare professional.

Can you overdose on risperidone?

Overdosage can occur with risperidone. The symptoms can include abnormal restless muscle movements, heart racing, dizziness, fainting, and somnolence. The response to overdosage should be to seek emergency medical care and call the Poison Control Helpline at 1-800-222-1222.

What interacts with risperidone?

Due to the potential need to adjust or monitor the medication, healthcare providers should be notified if one is taking clozapine, carbamazepine, fluoxetine, paroxetine, levodopa, or blood pressure medications. Any concomitant medication that causes drowsiness, including opiates and benzodiazepines, may result in dangerous drug interactions when taken with risperidone since it can heighten this effect. 

Risperidone should generally be avoided if you are taking any of the following medications:

• amifampridine

• apomorphine

• bromocriptine

• butalbital

• cabergoline

• ceritinib

• clonidine

• codeine

• doxylamine

• ethanol

• guanfacine

• hydrocodone

• isocarboxazid

• kava

• levodopa

• lofexidine

• metoclopramide

• midazolam

• oxybate

• phenelzine

• pitolisant

• pramipexole

• promethazine

• rotigotine transdermal

• thalidomide

• tranylcypromine

• trimethobenzamide

What happens when you mix risperidone and alcohol?

Alcohol must be avoided with risperidone. A dangerous degree of sedation and nervous system depression can occur.

Is it safe to take risperidone during pregnancy?

Based on limited safety data, caution is advised regarding taking risperidone during pregnancy but based on the potential harm of untreated schizophrenia and mania, it is used in some cases. Particular concern exists for use in the third trimester of pregnancy based on the potential for the newborn to have withdrawal symptoms or extrapyramidal symptoms.

There is also limited information on risperidone and breastfeeding. Some data shows that maternal risperidone doses of up to 6 mg per day may produce low levels in breast milk. Women who take risperidone should speak with their healthcare provider before breastfeeding.

Is lab monitoring done while taking risperidone?

Risperidone use requires significant monitoring, including for weight, glucose, cholesterol, and prolactin levels, which can rise during treatment. Conversely, blood cell counts can drop during risperidone therapy, therefore necessitating blood count checks. Based on the potential for electrical conduction changes, namely prolongation of the QT interval, an electrocardiogram may need to be checked. Close follow-up with a healthcare provider is essential while taking risperidone.

What are some common side effects of risperidone?

According to the FDA, common adverse reactions of Risperdal include:

• Somnolence (sleepiness, drowsiness, fatigue)

• Increased appetite

• Rhinitis (nasal inflammation), upper respiratory tract infection, coughing

• Dyspepsia (indigestion), nausea, vomiting, abdominal pain, constipation

• Urinary incontinence

• Increased saliva production and dry mouth

• Fever

• Parkinsonism, tremor, dystonia (involuntary muscle spasms), akathisia (an uncontrollable urge to move)

• Anxiety

• Dizziness

• Rash

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Related resources for risperidone dosages:

• Risperidone, Epocrates

• Risperidone for dogs and cats, PetPlace

• Risperidone and breastfeeding, Drugs and Lactation Database

• Risperdal drug information, FDA