Orap (Pimozide)

Pimozide acts on dopaminergic pathways to control tic and psychotic symptoms. It is indicated for:

• Tourette syndrome: reduces motor and vocal tics in children and adults.
• Chronic schizophrenia: helps control persistent psychotic symptoms when other agents are insufficient.
• Other tic disorders: alleviates severe motor tics unresponsive to first‑line therapy.

• Pimozide exerts its effect primarily by antagonizing dopamine D2 receptors in the central nervous system, with additional blockade of D1, D3 and certain serotonin (5‑HT2) receptors. This reduces dopaminergic neurotransmission, leading to decreased motor and psychotic activity.

Pimozide may cause a range of adverse reactions.

Common Side Effects

• Sedation: feeling unusually drowsy or sleepy.
• Extrapyramidal symptoms: muscle stiffness, tremor, or restlessness.
• Dry mouth: reduced salivation leading to discomfort.
• Constipation: slowed bowel movements.
• Blurred vision: temporary visual disturbances.
• Weight gain: increase in body weight over time.

Serious or Rare Side Effects

• Tardive dyskinesia: involuntary, repetitive movements.
• Neuroleptic malignant syndrome: high fever, muscle rigidity, autonomic instability.
• QT interval prolongation: risk of serious cardiac arrhythmias.
• Severe hypotension: marked drop in blood pressure.
• Agranulocytosis: dangerous reduction in white blood cells.
• Seizures: occurrence of convulsive episodes.

Before initiating pimozide therapy, consider the following precautions:

• Cardiac monitoring: obtain baseline ECG due to QT‑prolongation risk.
• CNS depression: avoid alcohol and other sedatives.
• Pregnancy: contraindicated; discuss risks with a specialist.
• Breastfeeding: not recommended as drug passes into milk.
• Drug interactions: review concomitant medications for CYP3A4 inhibitors.
• Renal/hepatic impairment: adjust dose in patients with organ dysfunction.
• Store at ambient temperature: keep in original packaging, protect from moisture.

Pimozide can interact with several medicines.

Major Interactions (Avoid)

• CYP3A4 inhibitors (e.g., ketoconazole, erythromycin): increase pimozide levels.
• QT‑prolonging agents (e.g., quinidine, sotalol): additive cardiac risk.
• Other antipsychotics: heightened extrapyramidal side effects.
• MAO inhibitors: risk of severe hypotension.
• Antiarrhythmics (e.g., amiodarone): potential cardiac toxicity.

Moderate Interactions (Monitor Closely)

• CYP3A4 inducers (e.g., rifampin): may reduce efficacy.
• Antihypertensives: possible additive blood‑pressure lowering.
• CNS depressants: increased sedation.
• Anticholinergics: heightened anticholinergic burden.
• Lithium: potential for neurotoxicity.