Novoris (Risperidone)

Risperidone is an atypical antipsychotic that acts on dopamine and serotonin pathways to treat several psychiatric conditions.

• Schizophrenia: reduces delusions, hallucinations and disorganized thinking.
• Bipolar I disorder (manic or mixed episodes): helps control mood swings and acute mania.
• Irritability associated with autistic disorder: lessens aggression, self‑injurious behavior and mood instability.
• Tourette syndrome (off‑label in some regions): may decrease tic frequency and severity.
• Psychosis in dementia (cautiously): may alleviate severe psychotic symptoms when non‑pharmacologic measures fail.

• Risperidone exerts its antipsychotic effect primarily by antagonizing dopamine D2 receptors and serotonin 5‑HT2A receptors in the central nervous system. This dual blockade modulates dopaminergic and serotonergic neurotransmission, leading to reduced psychotic symptoms and mood stabilization. The drug also shows affinity for alpha‑adrenergic and histamine H1 receptors, contributing to its side‑effect profile.

Risperidone may cause a range of adverse reactions, from mild to serious. Monitoring and patient education are essential.

Common Side Effects

• Drowsiness or sedation
• Weight gain
• Increased prolactin levels (galactorrhea, menstrual changes)
• Dizziness or orthostatic hypotension
• Constipation
• Dry mouth

Serious or Rare Side Effects

• Neuroleptic malignant syndrome
• Tardive dyskinesia or other movement disorders
• Severe hypotension or cardiovascular collapse
• Agranulocytosis or severe neutropenia
• Seizures
• Myocarditis or cardiomyopathy

Before initiating risperidone therapy, clinicians should consider several safety measures.

• Metabolic monitoring: regularly assess weight, glucose and lipid levels.
• Cardiovascular assessment: evaluate blood pressure and heart rate, especially in patients with pre‑existing disease.
• Extrapyramidal vigilance: watch for early signs of movement disorders.
• Discontinuation: avoid abrupt cessation to reduce withdrawal or rebound psychosis.
• Elderly with dementia: use only when benefits outweigh risks due to increased mortality.
• Store at ambient temperature: keep in the original container, protect from moisture and direct sunlight.

Risperidone can interact with other medicines, altering its efficacy or safety.

Major Interactions (Avoid)

• Strong CYP2D6 inhibitors (e.g., fluoxetine, paroxetine): may raise risperidone plasma concentrations.
• CNS depressants (e.g., benzodiazepines, opioids): additive sedation and respiratory depression.
• Antihypertensive agents: potentiation of hypotensive effects.

Moderate Interactions (Monitor Closely)

• Anticholinergic drugs: may mask extrapyramidal symptoms.
• Lithium: increased risk of neurotoxicity.
• Carbamazepine or other CYP3A4 inducers: may lower risperidone levels, reducing efficacy.