Risperidone

Risperidone is an antipsychotic medication that belongs to the class of atypical antipsychotics. It is used to treat a variety of mental and behavioral disorders. Risperidone was first approved for medical use in the 1990s and has been widely used in clinical practice since then.

Risperidone works by blocking or modulating receptors in the brain, including dopamine and serotonin receptors. This helps correct the imbalance of chemicals in the brain that is thought to be one of the causes of psychotic conditions.

Indications Risperidone

1. Schizophrenia: Risperidone may help reduce symptoms of schizophrenia such as hallucinations, delusions, disjointed thoughts, and immobility.
2. Bipolar Disorder: Within bipolar disorder, risperidone may help control manic episodes (periods of agitation or increased energy) and depressive episodes (periods of low mood).
3. Autistic Disorder: Risperidone may be used to reduce aggression, repetitive behavioral patterns, agitation, and other symptoms associated with autism in children and adolescents.
4. Behavioral Disorders in Children and Adolescents: Risperidone may be prescribed to treat aggression, agitation, self-destructive behavior, and other behavioral problems in children and adolescents.
5. Mental health disorders associated with dementia: Risperidone may be used to reduce aggression, anxiety, and psychotic symptoms in older adults with dementia.

Release form

1. Pills

Risperidone tablets are the most common form of release. They are available in various dosages such as 0.25 mg, 0.5 mg, 1 mg, 2 mg, 3 mg, and 4 mg. The tablets are intended to be taken orally, usually once or twice a day.

2. Soluble tablets (orodispersible tablets)

Risperidone soluble (orodispersible) tablets are designed for those who have difficulty swallowing regular tablets. These tablets dissolve in the mouth, making them easier to take. They are also available in different dosages.

3. Solution for oral administration

Risperidone in the form of an oral solution provides an alternative for patients who find it difficult to take tablets. The solution allows accurate dosage measurement, which is particularly useful if you need to slowly increase or decrease the dose.

4. Depo-injections (prolonged action)

Risperidone is also available in the form of extended-release injections that are administered intramuscularly (IM). These injections, known as risperidone depot or extended-release risperidone, are for the maintenance treatment of schizophrenia and other psychoses. The injections are usually given once every two weeks and can provide a more stable level of the drug in the blood, which is convenient for patients who have difficulty taking pills regularly.

Pharmacodynamics

1. Dopaminergic action: Risperidone is an antagonist of dopamine D2 and D3 receptors in the brain. This has the effect of blocking dopamine activity in the mesolimbic system, which may reduce positive symptoms of schizophrenia such as hallucinations and delusions.
2. Serotonergic action: Risperidone also has high affinity for serotonin receptors 5-HT2A and 5-HT7. This may help improve mood and cognitive function in patients with psychiatric disorders.
3. α1-adrenergic receptor antagonism: Risperidone blocks α1-adrenergic receptors, which may help improve some physical symptoms such as anxiety and agitation.
4. Histamine H1-receptor antagonism: Risperidone also has affinity for histamine H1 receptors, which may affect sleep and blood pressure.

Pharmacokinetics

1. Absorption: Risperidone is generally well absorbed after oral administration and rapidly reaches peak blood concentrations, usually in 1-2 hours.
2. Metabolism: Risperidone is metabolized in the liver, where it undergoes mainly oxidative processes, including hydroxylation and N-demethylation. The major metabolite of risperidone, 9-hydroxyriperidone, also has antipsychotic activity.
3. Excretion: Risperidone and its metabolites are mainly excreted through the kidneys and intestine. About 70% of the dose is excreted as metabolites, mainly through the urine, and the remainder through the intestine.
4. Semi-terminal period: In adults, the semi-terminal period of risperidone is approximately 20 hours and that of 9-hydroxyperidone is approximately 21 hours.
5. Interactions: Risperidone may interact with other drugs, including inhibitors and inducers of CYP2D6 and CYP3A4 isoenzyme, therefore, when concomitant administration with other drugs, the possibility of such interactions should be taken into account.

Dosing and administration

For adults in the treatment of schizophrenia:

• Starting dose: usually 2 mg per day.
• Maintenance dose: the dose can be gradually increased to 4-6 mg daily, depending on individual response and tolerability.
• Maximum dose: should not exceed 16 mg per day.

For adults and children over 15 years of age in the treatment of bipolar disorder:

• Starting dose: usually 2 mg per day.
• Maintenance dose: may be increased by 1 mg per day at one-day intervals, depending on response to treatment.

For children in the treatment of irritability associated with autistic disorders:

• Starting dose: depends on the weight of the child. For children weighing less than 20 kg, the starting dose is 0.25 mg per day. For children weighing more than 20 kg, the starting dose is 0.5 mg per day.
• Maintenance dose: the dose may be increased by 0.25 mg (for children weighing less than 20 kg) or 0.5 mg (for children weighing more than 20 kg) every other day, depending on clinical response and tolerability.
• Maximum dose: usually does not exceed 3 mg per day.

Method of Application:

• Risperidone can be taken with or without food, depending on your preference and your doctor's recommendations.
• The orodispersible tablets should be placed on the tongue, where they will dissolve, and should be drunk with water.
• The oral solution should be measured using a special dosing device that is usually supplied with the medicine.
• Prolonged-acting injections are administered intramuscularly by a health care provider.

Use Risperidone during pregnancy

The use of risperidone during pregnancy should only be used for strict medical reasons and under the supervision of a doctor. Risperidone is an atypical antipsychotic medication that is often used to treat schizophrenia, bipolar disorder, and other mental illnesses. However, its safety during pregnancy has not yet been established.

Some studies suggest that certain fetal health risks may occur with the use of risperidone during pregnancy, including preterm labor, low birth weight, and other congenital abnormalities. However, the decision to use risperidone during pregnancy should be based on an assessment of the benefits to the mother compared to the potential risks to the fetus.

Contraindications

1. Hypersensitivity: People with known hypersensitivity to risperidone or any other component of the drug should not use it.
2. Parkinsonism: The use of risperidone may increase symptoms of parkinsonism, including tremors, muscle rigidity, and movement disorders.
3. Cerebrovascular disease: In patients with cerebrovascular disease, such as stroke or cerebral atherosclerosis, the use of risperidone may increase the risk of serious adverse effects, including death.
4. Dementia: Risperidone may increase the risk of death in elderly patients with dementia, especially those with psychosis and anxiety.
5. Paralytic Intestinal Obstruction: In patients with a history of paralytic intestinal obstruction, risperidone should be used with caution as it may exacerbate this condition due to its anticholinergic properties.
6. Pregnancyand lactation: The use of risperidone during pregnancy or lactation should be performed only when strictly necessary and under medical supervision.
7. Pediatric age: The use of risperidone in children under a certain age should be performed only under the prescription of a physician and under his supervision.
8. Paralytic Intestinal Obstruction: In patients with a history of paralytic intestinal obstruction, risperidone should be used with caution as it may exacerbate this condition due to its anticholinergic properties.

Side effects Risperidone

1. Drowsiness and fatigue.
2. Dizziness.
3. Increased or decreased appetite.
4. Weight gain.
5. Worry and anxiety.
6. Dry mouth.
7. Digestive disorders such as constipation or diarrhea.
8. Tremor (shaking) or muscle weakness.
9. Menstrual disorders in women.
10. Problems with sexual function.

In addition, in rare cases, risperidone can cause more serious side effects such as:

1. Extrapyramidal symptoms such as tremors, muscle rigidity, inability to control movements (psychomotor agitation).
2. Hyperprolactinemia (elevated levels of prolactin in the blood), which can lead to menstrual cycle problems, breast enlargement in men and women, and decreased libido and erectile dysfunction.
3. Increased blood sugar levels and risk of developing diabetes.
4. Increased risk of cardiovascular disease.
5. Liver disorders.
6. Potentially serious allergic reactions.

Overdose

1. Drowsiness or stunned.
2. Balance incontinence or dizziness.
3. Disorders of consciousness, including coma.
4. Muscle weakness or urinary incontinence.
5. Elevated heart rate or blood pressure.
6. Extrapyramidal symptoms such as tremors, seizures, or muscle contractions.
7. Psychomotor agitation or restlessness.
8. Manifestations of aggression or behavioral disorders.

Interactions with other drugs

1. Centrally acting agents: Concomitant use of risperidone with other psychotropic agents such as sedatives, alcohol, sleeping pills and analgesics may increase sedation and central nervous system depression.
2. Drugs depressing the central nervous system: Interaction of risperidone with other drugs, such as barbiturates, anticholinergic drugs and antiparkinsonian agents, may lead to increased depressant effect on the central nervous system.
3. Drugs affecting the cardiovascular system: Risperidone may increase the hypotensive effect of blood pressure-lowering drugs, as well as cause arrhythmias in concomitant use with other drugs affecting the cardiovascular system.
4. Drugs metabolized through the cytochrome P450 system: Risperidone may affect the metabolism of other drugs metabolized through isoenzymes of the cytochrome P450 system, which may lead to changes in their concentration in the blood and possible strengthening or weakening of the effect of these drugs.
5. Drugs that cause prolongation of the QT interval: Concomitant use of risperidone with other drugs that may cause prolongation of the QT interval (e.g., some antiarrhythmic drugs, antidepressants, antibiotics) may increase the risk of cardiac arrhythmias.

Storage conditions

Risperidone should normally be stored in the original package at 20°C to 25°C, protected from moisture and direct exposure to sunlight. Detailed instructions on storage conditions are always indicated on the package or in the accompanying information for the drug. If you have any further questions regarding the storage of risperidone, it is recommended that you consult your doctor or pharmacist.