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iloperidone

Antipsychotic

Brand: Fanapt

Published 2025-09-19 · Last reviewed 2025-09-26 · 5 references

Content sourced from FDA labeling (DailyMed) and peer-reviewed literature.

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At a glance

Class: Antipsychotic·Typical dose: Titrate: Day 1 1 mg BID → Day 2 2 mg BID → Day 3 4 mg BID → Day 4 6 mg BID → Day 5 8 mg BID; maintenance target 6–12 mg BID (12–24 mg/day).·Half-life: Single-dose mean 18 h; Steady-state mean 23 h·LAI available: No

Class: Antipsychotic
Typical dose: Titrate: Day 1 1 mg BID → Day 2 2 mg BID → Day 3 4 mg BID → Day 4 6 mg BID → Day 5 8 mg BID; maintenance target 6–12 mg BID (12–24 mg/day).
Half-life: Single-dose mean 18 h; Steady-state mean 23 h
LAI available: No

Quick answers

What is iloperidone?: Iloperidone (brand Fanapt) is a second-generation antipsychotic approved in 2009 for adult schizophrenia and is often considered when patients need a lower-EPS option.
What is Fanapt?: Fanapt is a brand name for iloperidone.
What is Fanapt (iloperidone) used for?: Label indications include: Schizophrenia (adults).
What drug class is Fanapt (iloperidone)?: Atypical Antipsychotic.
What is the mechanism of action of Fanapt (iloperidone)?: Dopamine D2/D3 and serotonin 5-HT2A antagonist with high affinity for adrenergic α1 receptors, requiring slow titration.
What strengths does Fanapt (iloperidone) come in?: Tablets: 1 mg, 2 mg, 4 mg, 6 mg, 8 mg, 10 mg, 12 mg.
Is Fanapt (iloperidone) a controlled substance?: No — it is not scheduled as a controlled substance under U.S. federal law.

General information

Iloperidone (brand Fanapt) is a second-generation antipsychotic approved in 2009 for adult schizophrenia and is often considered when patients need a lower-EPS option.

Potent antagonism at adrenergic α1 receptors necessitates a structured titration schedule to mitigate orthostatic hypotension, syncope, and tachycardia.

Tablet strengths from 1 mg to 12 mg enable fine-tuned dosing; therapy must restart at 1 mg twice daily if treatment is interrupted for three or more consecutive days.

The compare tool, the evidence library, and the Schizophrenia hub support side-by-side review of low-EPS alternatives and follow-up planning.

U.S. approvals

Schizophrenia (adults) (2009)

Formulations & strengths

Tablets: 1 mg, 2 mg, 4 mg, 6 mg, 8 mg, 10 mg, 12 mg.

Generic availability

Generic tablets available in the U.S. market.

Use is tempered by slow titration and QTc warnings, yet iloperidone can be useful when other SGAs cause EPS or metabolic burden.

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Mechanism of action

Refer to the Glossary entry on Neurotransmitters for background on receptor systems involved in serious mental illness.

Antagonism at dopamine D2/D3 and serotonin 5-HT2A receptors delivers antipsychotic efficacy with a comparatively low EPS profile.

High affinity for α1-adrenergic receptors underlies orthostatic hypotension and reflex tachycardia, while 5-HT6/5-HT7 antagonism may support cognitive effects.

Ki ≈0.3 nM at α1 receptors and ≈1.5 nM at 5-HT2A receptors.
D2/D3 antagonism (Ki ≈4 nM) provides antipsychotic effect.
Minimal muscarinic and histaminergic activity limits anticholinergic side effects.

Metabolism & pharmacokinetics

Oral bioavailability ~96% with peak concentrations 2–4 hours after dosing; active metabolites P88 and P95 contribute to activity.
Metabolized via CYP2D6 and CYP3A4; elimination half-life averages 18 hours in extensive metabolizers and ~23 hours in poor metabolizers.
Roughly 45% of drug-related material is recovered in urine and 50% in feces; protein binding ~95%.
Steady state is achieved within 3–4 days; hepatic or renal impairment warrants slower titration and close monitoring.

Dosing & administration

Titrate: Day 1 1 mg BID → Day 2 2 mg BID → Day 3 4 mg BID → Day 4 6 mg BID → Day 5 8 mg BID; maintenance target 6–12 mg BID (12–24 mg/day).
Target and maximum doses are typically reduced by 50% in CYP2D6 poor metabolizers or when co-administered with strong CYP2D6 inhibitors (fluoxetine, paroxetine).
Dose reductions (often ~50%) are commonly used with strong CYP3A4 inhibitors (ketoconazole, clarithromycin), with attention to QTc. Strong CYP3A4 inducers (carbamazepine, rifampin) can markedly reduce exposure and are generally avoided.
If therapy is interrupted for ≥3 consecutive days, titration is typically restarted at 1 mg twice daily to reduce orthostatic events.

Adverse effects

FDA boxed warnings

Antipsychotics increase mortality in elderly patients with dementia-related psychosis; iloperidone is not approved for this population.

Common side effects (≥10%)

Orthostatic hypotension/syncope: Most pronounced during titration; counseling often includes hydration and slow position changes.
Tachycardia and palpitations: Pulse is often monitored, particularly with concomitant QTc-prolonging drugs.
Somnolence and dizziness: May improve after the first week; some dosing strategies shift a larger portion to bedtime when tolerated.
Weight gain: Average gain is modest but metabolic labs are still typically obtained.
Nasal congestion: Common due to α1 blockade; supportive care usually sufficient.

Other notable effects

QTc prolongation (mean increase ≈9 msec at 12 mg BID)—baseline ECG is often considered in at-risk patients, and minimizing additive QTc drugs can reduce overall risk.
Low-to-moderate risk of akathisia or EPS—ongoing monitoring is still common despite a favorable profile.
Rare neuroleptic malignant syndrome or tardive dyskinesia warrant prompt evaluation if rigidity or new movements emerge.

Interactions

Strong CYP2D6 inhibitors or poor metabolizer status often require halving the iloperidone dose.
Strong CYP3A4 inhibitors elevate exposure—dose reduction by ~50% is common, with QTc monitoring often considered.
Strong CYP3A4 inducers can markedly reduce serum levels and are generally avoided due to potential loss of efficacy.
Additive QTc prolongation with drugs such as amiodarone, sotalol, or methadone; ECG monitoring is often considered or alternatives may be preferred.
Concomitant antihypertensives, alcohol, or CNS depressants may potentiate hypotension and sedation.

Other useful information

Orthostatic vitals are often checked at baseline, during titration, and after dose increases.
Patient education often includes restarting titration if therapy is interrupted and reporting presyncope or palpitations.
Routine metabolic monitoring is continued even though average weight gain is limited overall.

References

Related hubs:Schizophrenia hub·Bipolar hub