Invega (Paliperidone)

Invega (paliperidone) is employed in the management of psychotic disorders that involve dopamine dysregulation.

• Schizophrenia: reduces positive and negative symptoms and helps prevent relapse.
• Schizoaffective disorder: stabilizes mood and psychotic features, improving overall functioning.
• Maintenance therapy: provides long‑term control of symptoms in chronic schizophrenia, supporting adherence through once‑daily dosing.

• Paliperidone exerts its antipsychotic effect primarily by antagonizing dopamine D2 receptors and serotonin 5‑HT2A receptors in the central nervous system. This dual blockade reduces dopaminergic hyperactivity linked to psychosis while modulating serotonergic pathways that influence mood and cognition. Additional moderate affinity for α1‑adrenergic and histamine H1 receptors contributes to its side‑effect profile but does not drive therapeutic efficacy.

Paliperidone may cause a range of adverse reactions, which are commonly categorized by frequency.

Common Side Effects

• Akathisia: inner restlessness and urge to move.
• Weight gain: increase in body weight and appetite.
• Somnolence: drowsiness or sleepiness during the day.
• Constipation: difficulty passing stool.

Serious or Rare Side Effects

• Neuroleptic malignant syndrome: life‑threatening reaction with fever, muscle rigidity and autonomic instability.
• Tardive dyskinesia: potentially irreversible involuntary movements of the face and limbs.
• Orthostatic hypotension: sudden drop in blood pressure upon standing, causing dizziness.
• Seizures: risk of convulsive episodes, especially in predisposed individuals.

When prescribing Invega, clinicians should consider several precautionary measures to ensure patient safety.

• Pregnancy: Category B; use only if potential benefit justifies potential risk to the fetus.
• Breastfeeding: limited data; weigh maternal benefit against possible infant exposure.
• Cardiovascular: monitor ECG and blood pressure for QT prolongation or orthostatic changes.
• Metabolic: assess weight, glucose, and lipid levels regularly during therapy.
• Elderly: increased sensitivity to orthostatic hypotension; initiate at lower dose and titrate cautiously.
• Store at ambient temperature: keep below 25 °C, retain original packaging, and protect from moisture.

Paliperidone can interact with other medicines, altering its plasma concentration or additive pharmacologic effects.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole): may increase paliperidone levels and risk of toxicity.
• CNS depressants (e.g., benzodiazepines): can produce additive sedation and respiratory depression.
• Anticholinergic agents: may worsen cognitive impairment and increase anticholinergic burden.

Moderate Interactions (Monitor Closely)

• CYP3A4 inducers (e.g., carbamazepine, phenytoin): may reduce paliperidone exposure and diminish efficacy.
• Antihypertensive drugs: may enhance orthostatic hypotension, requiring blood pressure monitoring.
• Antidiabetic agents: monitor glucose as paliperidone can affect glycemic control.