Understanding the Most Common and Serious Side Effects of Risperidone

Risperidone is an antipsychotic medication that is used to treat a variety of psychiatric conditions, including schizophrenia, bipolar disorder, and irritability associated with autism. While risperidone can be an effective treatment option for these conditions, it can also cause side effects. Some of the most common side effects of risperidone include symptoms that mimic Parkinson’s disease, gastrointestinal symptoms, dry mouth, tiredness and sleepiness, insomnia, anxiety, increased appetite leading to weight gain, and cough and throat pain (more common in children). However, risperidone can also cause rare but serious side effects that require medical attention, including neuroleptic malignant syndrome (NMS), tardive dyskinesia, metabolic changes, impaired cognitive and motor function, hyperprolactinemia, orthostatic hypotension, low white blood cell levels, and long and painful erections (priapism). People with dementia-related psychosis should not take risperidone, and other groups of people should use caution when taking it.

In this article, we will discuss the most common and serious side effects of risperidone, as well as their impact on health, and some strategies to manage them. We will also review relevant studies on this topic to provide a comprehensive understanding of the potential risks and benefits of risperidone use.

Common Side Effects of Risperidone

Symptoms that Mimic Parkinson’s Disease (Parkinsonism)

One of the most common side effects of risperidone is Parkinsonism, which refers to a group of symptoms that affect movement, including restlessness (akathisia), stiff muscles, and tremor. Parkinsonism is caused by a decrease in dopamine levels in the brain, and risperidone can block dopamine receptors, leading to these symptoms. Parkinsonism can be managed with medication adjustments or the addition of medications that increase dopamine levels, such as levodopa.

Gastrointestinal Symptoms

Another common side effect of risperidone is gastrointestinal symptoms, such as nausea, stomach discomfort, constipation, and vomiting. These symptoms may occur because risperidone can slow down the movement of the digestive tract, leading to slower digestion and absorption of food. Gastrointestinal symptoms can be managed with dietary modifications, such as eating smaller, more frequent meals, increasing fiber intake, and staying hydrated.

Dry Mouth

Dry mouth is a common side effect of risperidone and can be caused by decreased saliva production. This can lead to discomfort, difficulty speaking, and an increased risk of dental problems, such as tooth decay and gum disease. Drinking plenty of water, avoiding caffeine and alcohol, and using sugar-free gum or candy can help manage dry mouth.

Tiredness and Sleepiness

Risperidone can cause tiredness and sleepiness, which can affect daily activities and quality of life. These symptoms may be due to the sedative effects of risperidone, which can affect certain brain chemicals that regulate sleep and wakefulness. Tiredness and sleepiness can be managed by adjusting the timing and dosage of risperidone, as well as practicing good sleep hygiene, such as having a consistent sleep schedule, avoiding caffeine and electronics before bedtime, and creating a comfortable sleep environment.

Insomnia

While risperidone can cause tiredness and sleepiness, it can also cause insomnia, which is difficulty falling or staying asleep. Insomnia can be caused by an overactive mind or increased anxiety, which can be side effects of risperidone. Insomnia can be managed by practicing good sleep hygiene, such as avoiding electronics and stimulating activities before bedtime, engaging in relaxation techniques, and talking to a healthcare provider about medication adjustments or the addition of sleep aids.

Anxiety

Anxiety can be a side effect of risperidone, particularly when starting or adjusting the medication. Anxiety can be caused by the sedative effects of risperidone, as well as changes in certain brain chemicals that regulate mood and anxiety. Anxiety can be managed with relaxation techniques, such as deep breathing and mindfulness, as well as medication adjustments or the addition of anti-anxiety medications.

Increased Appetite Leading to Weight Gain

One of the most common and concerning side effects of risperidone is increased appetite leading to weight gain. Risperidone has been found to increase levels of the hormone ghrelin, which stimulates appetite, and decrease levels of the hormone leptin, which suppresses appetite. In addition, risperidone has been found to decrease resting metabolic rate, which can lead to fewer calories burned at rest. Finally, risperidone has also been found to alter insulin sensitivity, which can lead to increased fat storage.

Weight gain associated with risperidone can have significant health implications, including an increased risk of developing type 2 diabetes, heart disease, and other health problems. In addition, weight gain can also have a negative impact on mental health, as it can lead to decreased self-esteem and worsen symptoms of depression and anxiety. A study conducted in 2016 found that patients with schizophrenia who gained weight due to risperidone treatment had a higher risk of developing metabolic syndrome, a collection of risk factors that increase the risk of heart disease and diabetes.

Weight gain associated with risperidone can be challenging to manage, but there are several strategies that can help. These strategies include dietary modifications, exercise, and medication adjustments.

Dietary Modifications

Dietary modifications can help manage weight gain associated with risperidone. Eating a healthy, balanced diet that is low in calories and high in nutrients can help prevent excessive weight gain. A registered dietitian can help develop a personalized meal plan that meets an individual’s nutritional needs while also promoting weight management. In addition, reducing the intake of high-calorie, high-fat, and high-sugar foods and beverages can also be helpful.

Exercise

Regular exercise can also help manage weight gain associated with risperidone. Exercise can increase energy expenditure, improve cardiovascular health, and promote weight loss. A combination of aerobic exercise, such as walking or cycling, and resistance training, such as weight lifting or bodyweight exercises, can be effective in managing weight gain. It is recommended to aim for at least 150 minutes of moderate-intensity exercise per week.

Medication Adjustments

In some cases, medication adjustments may be necessary to manage weight gain associated with risperidone. A healthcare professional may adjust the dosage of risperidone or switch to a different medication that is less likely to cause weight gain. However, it is important to note that any medication changes should be made under the guidance and supervision of a healthcare professional.

Serious Side Effects of Risperidone

While the most common side effects of risperidone can be challenging, there are also some rare but serious side effects that require medical attention. These side effects include:

Neuroleptic Malignant Syndrome (NMS)

Neuroleptic malignant syndrome (NMS) is a rare but serious reaction to medications that lower dopamine levels, including risperidone. It is characterized by rigid muscles, high fever, and delirium (severe confusion or disorientation). If you experience any signs of NMS, such as muscle stiffness, fever, rapid heartbeat, sweating, or confusion, you should stop taking risperidone immediately and seek medical attention.

Tardive Dyskinesia

Tardive dyskinesia is a rare but irreversible movement disorder that can occur with long-term use of antipsychotic medications, including risperidone. It is characterized by involuntary, repetitive movements of the face, mouth, and limbs. Tardive dyskinesia can be difficult to treat, and there is no known cure. The risk of developing tardive dyskinesia increases with higher doses and longer durations of antipsychotic use. If you experience any signs of tardive dyskinesia, such as involuntary movements, you should speak with a healthcare professional.

Metabolic Changes

Risperidone can cause metabolic changes, including high blood sugar, abnormal cholesterol levels, and weight gain. These metabolic changes can increase the risk of developing heart disease, stroke, and other health problems. Healthcare professionals may monitor blood sugar and cholesterol levels more closely in patients taking risperidone. In addition, lifestyle modifications, such as dietary changes and exercise, can also help manage metabolic changes associated with risperidone.

Impaired Cognitive and Motor Function

Risperidone can impair cognitive and motor function, which can lead to drowsiness, falls, and other accidents. This is especially true for older adults, those with medical conditions that affect brain function, and those taking other medications that affect the brain. Healthcare professionals may advise against driving or operating heavy machinery while taking risperidone.

Hyperprolactinemia

Risperidone is most likely to raise prolactin levels among all atypical antipsychotics. High prolactin levels can cause irregular periods, mood changes, and fertility issues in women, as well as lower sex drive, breast development, and erectile dysfunction in men. Healthcare professionals may monitor prolactin levels in patients taking risperidone.

Orthostatic Hypotension

Orthostatic hypotension is a drop in blood pressure when changing positions, such as standing up from a seated position. Risperidone can cause orthostatic hypotension, which can lead to dizziness or fainting. This can increase the risk of falls and other accidents. Healthcare professionals may advise caution when changing positions and may adjust the dosage of risperidone to manage orthostatic hypotension.

Low White Blood Cell Levels

Risperidone can cause low white blood cell levels, which can increase the risk of infections. This is especially true for patients with a history of low white blood cell levels. Healthcare professionals may monitor white blood cell levels in patients taking risperidone.

Long and Painful Erections (Priapism)

Long and painful erections, known as priapism, can occur with risperidone use. This is a rare but serious side effect that requires immediate medical attention. If left untreated, priapism can cause permanent damage to the penis. Healthcare professionals may advise patients to seek medical attention immediately if they experience a prolonged erection.

Who Should Use Caution When Taking Risperidone?

In addition to patients with dementia-related psychosis, there are other groups of patients who should use caution when taking risperidone. These groups include:

  • Patients with a history of seizures: Risperidone can lower the seizure threshold, which can increase the risk of seizures in patients with a history of seizures.
  • Patients with diabetes: Risperidone can cause metabolic changes, including high blood sugar, which can worsen diabetes control.
  • Patients at risk for aspiration pneumonia: Risperidone can cause sedation and impair cognitive function, which can increase the risk of aspiration pneumonia in patients who are at risk, such as those with swallowing difficulties.
  • Patients exposed to extreme temperatures: Risperidone can impair the body’s ability to regulate temperature, which can increase the risk of heat stroke or hypothermia in patients exposed to extreme temperatures.
  • Patients with phenylketonuria: Risperidone contains phenylalanine, which can be harmful to patients with phenylketonuria, a metabolic disorder.

Conclusion

Risperidone is a commonly used antipsychotic medication that can be effective in treating a variety of psychiatric conditions. However, it can also cause side effects, both common and rare, that can impact an individual’s quality of life and health. It is important for patients to discuss potential side effects with their healthcare professionals before starting risperidone and to report any side effects they experience during treatment. With proper management and monitoring, the benefits of risperidone can outweigh the potential risks.


There are various forms of drugs available, such as tablets or liquids, and each may have a separate patient information leaflet (PIL) for different doses. It is important to refer to the PIL for the specific form and dose of the drug that you have been prescribed.

You can search for further information and PILs on websites such as: