Iloperidone is an atypical antipsychotic indicated for the treatment of schizophrenia in adults. It offers a unique receptor binding profile with potentially lower risk of extrapyramidal symptoms compared to typical antipsychotics.
Clinical Overview
Primary Clinical Applications
Iloperidone is effective for both positive and negative symptoms of schizophrenia. Its balanced receptor profile may provide antipsychotic efficacy while minimizing movement-related side effects. Evidence of activity in acute manic and mixed episodes of bipolar I disorder has been reported, but bipolar I disorder is not an FDA-approved indication in the United States.
Mechanism and Pharmacological Profile
Iloperidone antagonizes dopamine D2 and D3 receptors, serotonin 5-HT2A receptors, and has affinity for norepinephrine alpha-1 adrenergic receptors. This receptor profile contributes to its antipsychotic efficacy while potentially reducing extrapyramidal side effects compared to typical antipsychotics.
Dosing and Tolerability
Iloperidone requires slow dose titration over the first week to minimize orthostatic hypotension. The gradual titration schedule is essential for tolerability, particularly regarding cardiovascular effects. Once stabilized, most patients achieve therapeutic benefit in the 6-12 mg twice daily range.
Key Clinical Points
Seven-day titration is not optional
Starting at 1 mg twice daily and stepping up over a week exists solely to manage orthostatic hypotension from alpha-1 blockade. Skipping steps to reach a therapeutic dose sooner reliably produces syncope.
Slow onset follows from slow titration
Because a full week is needed to reach the 6 to 12 mg twice-daily target range, iloperidone is poorly suited to acute psychosis where rapid control is required.
Halve the dose for CYP2D6 poor metabolisers
The same 50 percent reduction applies with strong CYP2D6 or CYP3A4 inhibitors. Where both are present the effect compounds.
QT prolongation warrants ECG in at-risk patients
Monitor in anyone with cardiac risk factors or on other QT-prolonging agents. Orthostatic hypotension and tachycardia are among the most commonly reported effects.
Schizophrenia is the US indication
Approved for schizophrenia in adults. Bipolar I disorder is not an FDA-approved indication in the United States, notwithstanding evidence of activity in manic and mixed episodes.
Prescribing Information
Dosing & Administration
Schizophrenia – Adults:
- Day 1: 1 mg twice daily
- Day 2: 2 mg twice daily
- Day 3: 4 mg twice daily
- Day 4: 6 mg twice daily
- Day 5-7: 8 mg twice daily
- Target range: 6-12 mg twice daily
- Maximum: 12 mg twice daily
Bipolar I Disorder (Manic/Mixed Episodes):
- Same titration schedule as schizophrenia
- Effective range: 6-12 mg twice daily
Administration:
- Take with or without food
- Titration schedule must be followed to minimize orthostatic hypotension
Indications
- Treatment of schizophrenia in adults
- Note: Bipolar I disorder is not an FDA-approved indication in the US
Contraindications
- Hypersensitivity to iloperidone or any component
- No absolute contraindications, but caution in cardiovascular disease
Warnings & Precautions
- Boxed Warning: Increased mortality in elderly patients with dementia-related psychosis
- QT prolongation: Monitor ECG in patients with cardiac risk factors
- Orthostatic hypotension: Slow titration required, monitor blood pressure
- Neuroleptic malignant syndrome: Rare but serious risk
- Tardive dyskinesia: Risk with long-term use
- Metabolic changes: Monitor glucose, lipids, and weight
Drug Interactions
- Strong CYP2D6 inhibitors: Reduce iloperidone dose by 50%
- Strong CYP3A4 inhibitors: Reduce iloperidone dose by 50%
- CYP2D6 poor metabolizers: Reduce dose by 50%
- QT-prolonging drugs: Use caution, monitor ECG
Adverse Reactions
Common (≥5%):
- Dizziness, dry mouth, fatigue, nasal congestion
- Orthostatic hypotension, weight gain, tachycardia
Metabolic:
- Weight gain, hyperglycemia, dyslipidemia
Cardiovascular:
- QT prolongation, orthostatic hypotension
Special Populations
- CYP2D6 poor metabolizers: Reduce dose by 50%
- Hepatic impairment: Use caution, may require dose reduction
- Renal impairment: No specific dose adjustment recommended
- Elderly: Increased mortality risk in dementia-related psychosis
- Pregnancy: Category C – use only if benefits outweigh risks
Medical Disclaimer: This information is for educational purposes only and is not intended as medical advice. Always consult with qualified healthcare professionals before making any treatment decisions. Individual patient circumstances may vary significantly.
