Drug Monograph
Ziprasidone
Geodon (brand name)
Pharmacokinetic Profile
Half-Life
6–7 h (oral); 2–5 h (IM)
Metabolism
Aldehyde oxidase (~67%); CYP3A4 (~33%)
Protein Binding
>99% (albumin, α1-acid glycoprotein)
Bioavailability
~60% (with food); halved if fasted
Volume of Distribution
1.5 L/kg
Clinical Information
Drug Class
Atypical Antipsychotic (5-HT2A/D2 Antagonist)
Available Doses
Capsules: 20, 40, 60, 80 mg; IM: 20 mg/mL vial
Route
Oral (BID with food), Intramuscular
Renal Adjustment
Oral: none; IM: caution (cyclodextrin excipient)
Hepatic Adjustment
No data; use with caution
Pregnancy
Neonatal EPS/withdrawal risk (3rd trimester)
Lactation
Use with caution; monitor infant
Schedule / Legal Status
Not a controlled substance
Generic Available
Yes
Black Box Warning
Yes (increased mortality in elderly dementia)
QT Prolongation
Yes — ~10 msec increase at max dose; greater than risperidone, olanzapine, quetiapine, haloperidol
Indications
| Indication | Approved Population | Therapy Type | Status |
|---|---|---|---|
| Schizophrenia | Adults | Monotherapy | FDA Approved |
| Bipolar I — acute manic/mixed episodes | Adults | Monotherapy | FDA Approved |
| Bipolar I — maintenance | Adults | Adjunctive to lithium or valproate | FDA Approved |
| Acute agitation in schizophrenia | Adults (IM formulation) | Acute IM injection | FDA Approved |
Ziprasidone was approved in 2001 and occupies a distinctive niche among atypical antipsychotics. Its receptor profile combines potent 5-HT2A antagonism with D2 blockade plus 5-HT1A partial agonism and weak noradrenaline/serotonin reuptake inhibition. The drug carries a notable QT-prolongation liability that the FDA specifically advises clinicians to weigh when selecting among available treatments. Ziprasidone is not approved for any paediatric indication, and a trial in adolescents with bipolar I disorder did not support efficacy.
Off-Label Uses
Treatment-resistant depression (augmentation) — Limited open-label data suggest benefit when added to antidepressants. Evidence quality: Low.
ICU delirium / acute agitation (non-schizophrenia) — Used in emergency settings for rapid tranquillisation; IM formulation permits fast onset. Evidence quality: Moderate.
Bipolar II hypomania — Sometimes used based on extrapolation from bipolar I data. Evidence quality: Low.
Dosing
Adult Dosing by Clinical Scenario
| Clinical Scenario | Starting Dose | Maintenance Dose | Maximum Dose | Notes |
|---|---|---|---|---|
| Schizophrenia — acute episode | 20 mg BID | 20–80 mg BID | 100 mg BID (200 mg/day) | Adjust at ≥2-day intervals; take with food (≥500 kcal meal) Efficacy demonstrated 20–100 mg BID; doses >80 mg BID not generally recommended |
| Schizophrenia — relapse prevention | Continue acute dose | 20–80 mg BID | 80 mg BID | No additional benefit above 20 mg BID in maintenance trial (FDA PI); reassess periodically |
| Bipolar I mania — acute monotherapy | 40 mg BID | 60–80 mg BID | 80 mg BID (160 mg/day) | Increase to 60–80 mg BID on day 2; mean daily dose ~120 mg in trials More aggressive titration than schizophrenia |
| Bipolar I — maintenance (adjunct to Li/VPA) | Continue stabilising dose | 40–80 mg BID | 80 mg BID | Continue at same dose that achieved stabilisation; adjunct only (monotherapy maintenance not established) |
| Acute agitation in schizophrenia (IM) | 10–20 mg IM | PRN | 40 mg/day IM | 10 mg q2h or 20 mg q4h; max 3 consecutive days studied; switch to oral as soon as possible Do not co-administer oral + IM ziprasidone |
Clinical Pearl: Food Requirement
Ziprasidone absorption approximately doubles when taken with a meal of at least 500 kilocalories. This is the most food-dependent absorption of any oral antipsychotic. Patients who take ziprasidone on an empty stomach may receive sub-therapeutic exposure, potentially leading to apparent treatment failure. Always counsel patients to take capsules with a substantial meal or snack.
Pharmacology
Mechanism of Action
Ziprasidone binds with high affinity to dopamine D2 and D3 receptors, serotonin 5-HT2A, 5-HT2C, 5-HT1A, and 5-HT1D receptors, and the alpha-1 adrenergic receptor. It functions as a D2/5-HT2A antagonist with 5-HT1A partial agonist activity, a profile shared with other atypical antipsychotics but distinguished by an unusually high 5-HT2A-to-D2 binding ratio. Ziprasidone also demonstrates weak inhibition of serotonin and noradrenaline reuptake transporters in vitro, though the clinical significance of this property at therapeutic doses remains uncertain. Importantly, ziprasidone has moderate histamine H1 affinity and negligible muscarinic receptor binding, which accounts for its lower weight-gain potential and absence of anticholinergic side effects compared with many other agents in its class.
ADME Profile
| Parameter | Value | Clinical Implication |
|---|---|---|
| Absorption | Oral bioavailability ~60% (with food); absorption reduced up to 2-fold when fasted; Tmax 6–8 h (oral), ~60 min (IM); IM bioavailability ~100% | Must be taken with a meal of ≥500 kcal for reliable absorption; IM provides rapid onset for acute agitation |
| Distribution | Vd = 1.5 L/kg; >99% protein-bound (albumin, α1-acid glycoprotein); no displacement interactions with warfarin or propranolol | Moderate extravascular distribution; high protein binding unlikely to produce clinically relevant displacement interactions |
| Metabolism | Primarily aldehyde oxidase (~2/3 of clearance) via reduction; CYP3A4 (~1/3) via oxidation; CYP1A2 minor contributor; no clinically active metabolites at relevant concentrations | Unique among antipsychotics: aldehyde oxidase has no known clinically relevant inhibitors or inducers, providing relative PK stability; CYP3A4 interactions still possible but less impactful than for CYP-dependent drugs |
| Elimination | t½ ~6–7 h (oral), 2–5 h (IM); steady state in 1–3 days; clearance 7.5 mL/min/kg; excretion ~66% faeces, ~20% urine (<1% unchanged) | Short half-life necessitates BID dosing; rapid clearance of IM formulation means little drug accumulation and easy oral-to-IM transitions; no renal dose adjustment needed for oral; IM caution in renal impairment (cyclodextrin excipient) |
Side Effects
≥10%Very Common
| Adverse Effect | Incidence | Clinical Note |
|---|---|---|
| Somnolence / Sedation | 14–21% | Most frequently reported adverse effect; 14% in schizophrenia trials (vs 7% placebo); dose-related; led to discontinuation in only 0.3% |
| Headache | 13–18% | Common across all trial populations; placebo rates also high; drug-attributable component is modest based on meta-analysis data |
| Nausea | 10–12% | Tends to occur early in treatment; taking with food as required may help; more prominent with IM formulation |
| Dizziness | 10% | Related to alpha-1 blockade and orthostatic effects; common in bipolar mania trials; advise positional caution |
1–10%Common
| Adverse Effect | Incidence | Clinical Note |
|---|---|---|
| Extrapyramidal symptoms | 5–13% | Includes dystonia, hypertonia, tremor, dyskinesia; no individual EPS term >5% in schizophrenia trials; more frequent in bipolar mania trials |
| Akathisia | 5–10% | More prominent in bipolar mania (met the ≥5%/twice-placebo threshold) than in schizophrenia |
| Respiratory tract infection | 8% | Met the twice-placebo threshold in schizophrenia trials; likely partly coincidental but consistently reported |
| Constipation | 5–9% | Lower than with highly anticholinergic agents (ziprasidone lacks muscarinic binding) |
| Dyspepsia | 5–8% | Drug-attributable based on meta-analysis (RD 4 vs placebo); taking with food helps |
| Asthenia / Fatigue | 5–6% | Drug-attributable (RD 5 vs placebo); dose-related in schizophrenia trials |
| Rash | 4–5% | Most common reason for drug discontinuation (1%); if cause unidentifiable, FDA PI advises discontinuation |
| Abnormal vision | 3–6% | Met the twice-placebo threshold in bipolar mania trials |
| Vomiting | 5% | More common in bipolar mania trials than schizophrenia; usually transient |
| Weight gain | 0.4% (reported as AE); 10% had ≥7% gain | Mean gain only +0.5 kg (median) in schizophrenia; lowest weight-gain risk among SGAs; overweight patients may actually lose weight |
| Orthostatic hypotension / Syncope | Syncope 0.6% | Dose-related; related to alpha-1 antagonism; most likely during initial titration |
SeriousSerious (Regardless of Frequency)
| Adverse Effect | Estimated Frequency | Typical Onset | Required Action |
|---|---|---|---|
| QT prolongation / Torsade de pointes risk | Dose-related (~10 msec at 160 mg/day); QTc >500 msec: 0.06% | Any time; worse with electrolyte disturbances | Baseline ECG recommended; correct K+/Mg2+ before starting; discontinue if persistent QTc >500 msec; avoid all QT-prolonging co-medications |
| Neuroleptic malignant syndrome | Very rare | Days to weeks after initiation or dose change | Immediate discontinuation; ICU supportive care; monitor CK, renal function |
| Serotonin syndrome | Rare | Hours to days after adding serotonergic agent | Discontinue ziprasidone and all serotonergic drugs immediately; supportive care; contraindicated with MAOIs |
| DRESS / Stevens-Johnson syndrome | Very rare | Weeks to months | Immediate discontinuation; dermatology consultation; sometimes fatal |
| Tardive dyskinesia | Rare (<1%) | Months to years | Consider discontinuation; may be irreversible; screen with AIMS periodically |
| Seizures | 0.4% | Any time | Use with caution in patients with seizure history or lowered threshold |
| Leukopenia / Neutropenia | Rare | First months | Monitor CBC in patients with pre-existing low WBC; discontinue if significant decline |
DiscontinuationDiscontinuation Rates
Schizophrenia (Short-Term Trials)
~5% due to AEs
Top reasons: Rash (1%), somnolence (0.3%), nausea/vomiting
Bipolar Mania (Short-Term Trials)
~6% due to AEs
Top reasons: Akathisia, somnolence, EPS
| Reason for Discontinuation | Incidence | Context |
|---|---|---|
| Rash | 1% | Most common drug-specific cause; FDA advises discontinuation if cause not identifiable |
| Somnolence | 0.3% | Despite being the most common AE, rarely treatment-limiting |
| Akathisia / EPS | <1% | More commonly leads to discontinuation in bipolar trials than schizophrenia |
Managing QT-Related Safety
Although ziprasidone prolongs the QTc interval more than risperidone, olanzapine, quetiapine, or haloperidol in direct comparisons, torsade de pointes has not been observed in premarketing studies (with the caveat of limited exposure). Post-marketing reports exist but involve confounding factors. The practical approach is to avoid ziprasidone in patients with cardiac risk factors and to ensure electrolytes (potassium, magnesium) are normal before initiation and during treatment, especially if diuretics are co-prescribed.
Drug Interactions
Ziprasidone is primarily metabolised by aldehyde oxidase (which has no known clinically relevant modulators) and to a lesser extent by CYP3A4. It does not significantly inhibit or induce major CYP enzymes. The most critical interaction category involves QT-prolonging drugs, which are contraindicated in combination with ziprasidone.
MajorQT-Prolonging Drugs (Class Ia/III antiarrhythmics, thioridazine, mesoridazine, pimozide, moxifloxacin, etc.)
MechanismAdditive QTc prolongation
EffectIncreased risk of torsade de pointes and sudden cardiac death
ManagementContraindicated combination — do not co-prescribe; review all medications for QT liability before initiating ziprasidone
FDA PI — ContraindicationMajorMAOIs (phenelzine, tranylcypromine, linezolid, IV methylene blue)
MechanismIncreased serotonergic activity
EffectRisk of serotonin syndrome (hyperthermia, rigidity, myoclonus, autonomic instability)
ManagementContraindicated — 14-day washout after stopping MAOI before starting ziprasidone; 3-day washout after stopping ziprasidone before starting MAOI
FDA PI — Contraindication (2025)ModerateCarbamazepine
MechanismCYP3A4 induction
EffectReduces ziprasidone AUC by ~35%, potentially lowering efficacy
ManagementConsider higher ziprasidone doses or alternative mood stabiliser; monitor clinical response
FDA PIModerateKetoconazole / Strong CYP3A4 Inhibitors
MechanismCYP3A4 inhibition
EffectIncreases ziprasidone AUC by ~35–40%; however, no augmentation of QTc effect observed in PI study
ManagementMonitor for increased side effects; no specific dose reduction in PI, but clinical vigilance warranted
FDA PIModerateSSRIs / SNRIs / Triptans / Tramadol
MechanismAdditive serotonergic activity
EffectIncreased risk of serotonin syndrome (new warning in 2025 PI)
ManagementMonitor for serotonin syndrome symptoms; use lowest effective doses; discontinue both if syndrome suspected
FDA PI (2025)MinorLithium / Valproate
MechanismNo pharmacokinetic interaction (confirmed in PI studies)
EffectApproved combination for bipolar maintenance; additive sedation possible
ManagementNo dose adjustment needed; standard therapeutic drug monitoring for lithium/valproate
FDA PIMonitoring
- ECG (QTc)Baseline; if symptoms arise
RoutineBaseline ECG recommended given QT liability. Discontinue if persistent QTc >500 msec. Holter monitoring if dizziness, palpitations, or syncope occur. Routine serial ECGs not mandated by PI but many clinicians obtain them. - Serum Electrolytes (K+, Mg2+)Baseline; periodically if on diuretics
RoutineHypokalaemia and hypomagnesaemia increase QT prolongation risk. Correct electrolyte abnormalities before initiating and maintain normal levels during therapy. - Fasting Glucose & HbA1cBaseline, 12 weeks, then annually
RoutineStandard APA/ADA antipsychotic metabolic monitoring. Ziprasidone has a relatively favourable glucose profile with few reports of hyperglycaemia, but class-wide monitoring remains appropriate. - Lipid PanelBaseline, 12 weeks, then annually
RoutineZiprasidone appears metabolically neutral or slightly favourable for lipids in many trials, but monitoring is still recommended per consensus guidelines. - Body Weight & BMIBaseline, monthly for 3 months, then quarterly
RoutineLowest weight gain risk among SGAs. Patients with low BMI may gain weight; overweight patients may lose weight long-term. Still monitor as per APA guidelines. - EPS / Tardive DyskinesiaEach visit; AIMS every 6–12 months
RoutineScreen for acute EPS at each visit. Use AIMS for tardive dyskinesia screening, especially in long-term treatment and elderly patients. - Skin / RashEach visit; immediately if rash develops
Trigger-BasedRash is the most common cause of discontinuation (1%). Evaluate any rash promptly; discontinue if DRESS or SJS suspected. FDA advises discontinuation for rash of unknown aetiology. - CBC with DifferentialIf signs of infection or pre-existing low WBC
Trigger-BasedMonitor frequently during first months in patients with history of drug-induced leukopenia. Discontinue if ANC declines significantly.
Contraindications & Cautions
Absolute Contraindications
- Known history of QT prolongation including congenital long QT syndrome
- Recent acute myocardial infarction
- Uncompensated heart failure
- Concurrent use of QT-prolonging drugs — dofetilide, sotalol, quinidine, Class Ia/III antiarrhythmics, thioridazine, chlorpromazine, pimozide, sparfloxacin, moxifloxacin, and others (see PI for full list)
- Known hypersensitivity to ziprasidone
- Concurrent or recent (<14 days) MAOI use — risk of serotonin syndrome (new contraindication in 2025 label)
Relative Contraindications (Specialist Input Recommended)
- Dementia-related psychosis in elderly — increased mortality risk; not approved for this population
- Significant hepatic impairment — no dosing data available; expect increased exposure
- Bradycardia, hypokalaemia, or hypomagnesaemia — increased risk of QT prolongation and arrhythmia; correct before prescribing
Use with Caution
- Known cardiovascular or cerebrovascular disease — orthostatic hypotension risk
- History of seizures — seizures occurred in 0.4% of patients in clinical trials
- Conditions predisposing to aspiration — dysphagia reported with all antipsychotics
- Patients at risk for falls
- Renal impairment (IM formulation only) — cyclodextrin excipient cleared by renal filtration
FDA Boxed Warning
Increased Mortality in Elderly Patients with Dementia-Related Psychosis
Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death. Analyses of 17 placebo-controlled trials (modal duration 10 weeks) showed a death rate of approximately 4.5% in drug-treated patients versus 2.6% in placebo-treated patients. Deaths were primarily cardiovascular or infectious in nature. Ziprasidone is not approved for dementia-related psychosis.
QT Prolongation Advisory
The FDA PI specifically states that when choosing among available antipsychotics, prescribers should consider ziprasidone’s greater capacity to prolong the QTc interval compared with risperidone, olanzapine, quetiapine, and haloperidol. In many cases, the PI notes, this would lead to the conclusion that other drugs should be tried first. Whether ziprasidone actually increases the rate of torsade de pointes or sudden death remains unestablished, but the QT signal warrants careful patient selection and monitoring.
Patient Counselling
Purpose of Therapy
Ziprasidone works by adjusting the balance of dopamine and serotonin signals in the brain. It may reduce psychotic symptoms such as hallucinations and disordered thinking (schizophrenia) or stabilise mood and reduce manic episodes (bipolar disorder). Improvement may begin within the first week, but the full benefit typically takes 2–4 weeks to develop.
How to Take
Take ziprasidone capsules twice daily with a meal of at least 500 calories. Swallow capsules whole — do not open, crush, or chew. Taking the medication without food significantly reduces how much drug the body absorbs, which may make it less effective. Do not stop taking ziprasidone suddenly without discussing with a prescriber.
Taking with Food
Tell patientThis is one of the most important aspects of ziprasidone therapy. The body absorbs roughly twice as much medication when taken with a proper meal. A sandwich and a piece of fruit (about 500 calories) is sufficient. Skipping meals while taking ziprasidone may lead to the medication not working properly.
Call prescriberIf unable to eat regular meals consistently, as an alternative medication may be more appropriate.
Drowsiness
Tell patientSleepiness is the most common side effect and is usually most noticeable during the first 1–2 weeks. Avoid driving or operating heavy machinery until you know how the medication affects you. Taking the evening dose closer to bedtime may help.
Call prescriberIf excessive sleepiness persists beyond 2 weeks or interferes significantly with daily functioning.
Heart Rhythm Awareness
Tell patientZiprasidone can affect the electrical activity of the heart. While serious heart rhythm problems are very rare, it is important to inform the prescriber of all other medications being taken, including over-the-counter products and supplements. Stay well hydrated, as dehydration and electrolyte imbalances can increase this risk.
Call prescriberImmediately if experiencing fainting, irregular heartbeat, palpitations, or unusual dizziness.
Dizziness & Falls
Tell patientThe medication can cause lightheadedness when standing up quickly, especially in the first few days. Rise slowly from sitting or lying positions and stay well hydrated.
Call prescriberIf fainting occurs or if dizziness is persistent.
Skin Rash
Tell patientSkin rashes can occur with ziprasidone. While most are mild, in rare cases a serious allergic reaction (with fever, swollen lymph nodes, or skin blistering) can develop.
Call prescriberImmediately if any rash develops, particularly if accompanied by fever, facial swelling, or peeling skin.
Weight & Metabolic Health
Tell patientZiprasidone generally causes less weight gain than most other antipsychotics. Some patients experience no weight change or even modest weight loss. Maintaining a healthy diet and regular physical activity is still encouraged.
Call prescriberIf experiencing increased thirst, frequent urination, or unexplained weight changes.
Sources
Regulatory (PI / SmPC)
- Viatris Inc. GEODON (ziprasidone) Prescribing Information. Revised January 2025. FDA LabelPrimary source for all dosing, indications, contraindications, adverse reaction data, drug interactions, and the QT prolongation advisory used in this monograph.
- Pfizer Labs. GEODON (ziprasidone) Original Prescribing Information. 2001. FDA LabelOriginal approval label providing foundational pharmacokinetic data and initial clinical trial adverse-reaction tables.
Key Clinical Trials
- Daniel DG, Zimbroff DL, Potkin SG, et al. Ziprasidone 80 mg/day and 160 mg/day in the acute exacerbation of schizophrenia and schizoaffective disorder. Neuropsychopharmacology. 1999;20(5):491-505. doi:10.1016/S0893-133X(98)00090-2Pivotal fixed-dose RCT establishing the efficacy of ziprasidone 80 and 160 mg/day versus placebo in acute schizophrenia.
- Keck PE Jr, Versiani M, Potkin S, et al. Ziprasidone in the treatment of acute bipolar mania: a three-week, placebo-controlled, double-blind, randomized trial. Am J Psychiatry. 2003;160(4):741-748. doi:10.1176/appi.ajp.160.4.741Key RCT supporting the bipolar mania indication with dosing and safety data.
- Strom BL, Eng SM, Faich G, et al. Comparative mortality associated with ziprasidone and olanzapine in real-world use among 18,154 patients with schizophrenia. Am J Psychiatry. 2011;168(2):193-201. doi:10.1176/appi.ajp.2010.08040484Large observational study finding no excess cardiac mortality risk with ziprasidone versus olanzapine despite QT signal.
- Lieberman JA, Stroup TS, McEvoy JP, et al. Effectiveness of antipsychotic drugs in patients with chronic schizophrenia (CATIE). N Engl J Med. 2005;353(12):1209-1223. doi:10.1056/NEJMoa051688NIMH-funded effectiveness trial comparing SGAs; ziprasidone had favourable metabolic outcomes but higher discontinuation rates.
Guidelines
- American Psychiatric Association. Practice guideline for the treatment of patients with schizophrenia, 3rd edition. Am J Psychiatry. 2021;178(suppl). doi:10.1176/appi.books.9780890424841Current APA guideline listing ziprasidone among first-line antipsychotic options with consideration of QT risk.
- American Diabetes Association, American Psychiatric Association, et al. Consensus development conference on antipsychotic drugs and obesity and diabetes. Diabetes Care. 2004;27(2):596-601. doi:10.2337/diacare.27.2.596Establishes metabolic monitoring framework for all SGAs; notes ziprasidone has relatively favourable metabolic profile.
Mechanistic / Basic Science
- Schmidt AW, Lebel LA, Howard HR Jr, Bhatt SA. Ziprasidone: a novel antipsychotic agent with a unique human receptor binding profile. Eur J Pharmacol. 2001;425(3):197-201. doi:10.1016/S0014-2999(01)01131-2Foundational receptor-binding study characterising ziprasidone’s high 5-HT2A/D2 ratio and 5-HT1A agonism.
- Beedham C, Miceli JJ, Obach RS. Ziprasidone metabolism, aldehyde oxidase, and clinical implications. J Clin Psychopharmacol. 2003;23(3):229-232. doi:10.1097/01.jcp.0000084028.22282.f2Key paper explaining the aldehyde oxidase metabolic pathway and its pharmacokinetic implications for drug interactions.
Pharmacokinetics / Special Populations
- Gandelman K, Alderman JA, Glue P, et al. The impact of calories and fat content of meals on oral ziprasidone absorption. J Clin Psychiatry. 2009;70(1):58-62. doi:10.4088/JCP.08m04101RCT demonstrating that caloric content (not fat) drives ziprasidone absorption, establishing the 500 kcal minimum meal recommendation.
- Miceli JJ, Glue P, Alderman J, et al. Pharmacokinetics of ziprasidone administered intramuscularly in healthy subjects. J Clin Pharmacol. 2005;45(5):505-512. doi:10.1177/0091270004274433Characterises the rapid absorption (Tmax ~60 min), short half-life (2–5 h), and 100% bioavailability of IM ziprasidone.
- Citrome L. Ziprasidone HCl capsules for the treatment of acute manic or mixed episodes associated with bipolar disorder. Expert Opin Pharmacother. 2004;5(5):1129-1142. doi:10.1517/14656566.5.5.1129Comprehensive clinical review synthesising pharmacokinetics, efficacy, and safety across bipolar trials.