Invega (Paliperidone)

Invega (paliperidone) is used in the management of psychotic disorders within the schizophrenia spectrum.

• Schizophrenia: reduces acute psychotic symptoms and helps prevent relapse.
• Schizoaffective disorder: stabilizes mood and psychotic features.
• Maintenance treatment of schizophrenia: supports long‑term symptom control after initial stabilization.

• Paliperidone exerts its antipsychotic effect primarily by antagonizing dopamine D2 receptors and serotonin 5‑HT2A receptors. Additional blockade of α1‑adrenergic, H1 histamine, and 5‑HT7 receptors contributes to its efficacy and side‑effect profile. By modulating dopaminergic and serotonergic neurotransmission, the drug reduces positive and negative symptoms of schizophrenia and stabilizes mood disturbances. The combined receptor activity also influences cortical and limbic circuits involved in cognition and emotional regulation.

Paliperidone may be associated with a range of adverse reactions, which are generally categorized by frequency and severity.

Common Side Effects

• Headache: mild to moderate intensity.
• Insomnia: difficulty falling or staying asleep.
• Weight gain: increase in body mass index.
• Extrapyramidal symptoms: tremor, rigidity, or akathisia.
• Dizziness: sensation of light‑headedness or imbalance.
• Dry mouth: reduced salivation causing oral discomfort.

Serious or Rare Side Effects

• Neuroleptic malignant syndrome: life‑threatening reaction with fever and muscle rigidity.
• Tardive dyskinesia: persistent involuntary movements.
• Orthostatic hypotension: marked drop in blood pressure upon standing.
• Seizures: occurrence of convulsive episodes, especially in predisposed patients.

When prescribing paliperidone, clinicians should consider several precautionary measures to ensure safe use.

• Dose titration: start low and adjust based on response and tolerability.
• Cardiovascular monitoring: assess blood pressure and ECG for QT prolongation.
• Metabolic screening: monitor weight, glucose, and lipid levels regularly.
• Pregnancy and lactation: evaluate risk‑benefit; use only if clearly needed.
• Drug interactions: review concomitant medications for CYP450 substrates.
• Store at ambient temperature: keep below 25 °C, in original packaging, protected from moisture.

Paliperidone can interact with other medicines, affecting its plasma concentration or enhancing adverse effects.

Major Interactions (Avoid)

• Strong CYP3A4 inducers (e.g., carbamazepine, phenytoin): may markedly reduce paliperidone levels.
• Antihypertensive agents (e.g., alpha‑blockers): additive orthostatic hypotension risk.
• QT‑prolonging drugs (e.g., quinidine, haloperidol): increase risk of cardiac arrhythmias.

Moderate Interactions (Monitor Closely)

• CYP3A4 inhibitors (e.g., ketoconazole, erythromycin): may raise paliperidone exposure.
• CNS depressants (e.g., benzodiazepines, opioids): may enhance sedation.
• Anticholinergic agents: may worsen cognitive side effects.