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Ziprasidone
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| Clinical data | |
|---|---|
| Trade names | Geodon, others |
| AHFS/Drugs.com | Monograph |
| MedlinePlus | a699062 |
| License data |
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| Routes of administration | By mouth, intramuscular injection (IM) |
| Drug class | Atypical antipsychotic |
| ATC code | |
| Legal status | |
| Legal status | |
| Pharmacokinetic data | |
| Bioavailability | 60% (oral)[3]
100% (IM) |
| Metabolism | Liver (aldehyde reductase) |
| Elimination half-life | 7 to 10 hours[4] |
| Excretion | Urine and feces |
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| DrugBank | |
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| CompTox Dashboard (EPA) | |
| ECHA InfoCard | 100.106.954 |
| Chemical and physical data | |
| Formula | C21H21ClN4OS |
| Molar mass | 412.94 g·mol−1 |
| 3D model (JSmol) | |
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Ziprasidone, sold under the brand name Geodon among others, is an atypical antipsychotic used to treat schizophrenia and bipolar disorder.[5] It may be used by mouth and by injection into a muscle (IM).[5] The intramuscular form may be used for acute agitation in people with schizophrenia.[5]
Common side effects include tremors, tics, dizziness, dry mouth, restlessness, nausea, and mild sedation.[6][7] Although it can also cause weight gain, the risk is much lower than for other atypical antipsychotics.[8] How it works is not entirely clear but is believed to involve effects on serotonin and dopamine in the brain.[5]
Ziprasidone was approved for medical use in the United States in 2001.[5] The pills are made up of the hydrochloride salt, ziprasidone hydrochloride. The intramuscular form is the mesylate, ziprasidone mesylate trihydrate, and is provided as a lyophilized powder. In 2020, it was the 282nd most commonly prescribed medication in the United States, with more than 1 million prescriptions.[9][10]
Medical uses
[edit]Ziprasidone is approved by the US Food and Drug Administration (FDA) for the treatment of schizophrenia as well as acute mania and mixed states associated with bipolar disorder. Its intramuscular injection form is approved for acute agitation in schizophrenic patients for whom treatment with just ziprasidone is appropriate.[11]
In a 2013 study in a comparison of 15 antipsychotic drugs in effectiveness in treating schizophrenic symptoms, ziprasidone demonstrated mild-standard effectiveness. Ziprasidone was 15% more effective than lurasidone and iloperidone, approximately as effective as chlorpromazine and asenapine, and 9–13% less effective than haloperidol, quetiapine, and aripiprazole.[12] Ziprasidone is effective in the treatment of schizophrenia, though evidence from the CATIE trials suggests it is less effective than olanzapine, and equally as effective compared to quetiapine. There are higher discontinuation rates for lower doses of ziprasidone, which are also less effective than higher doses.[13]
Adverse effects
[edit]Ziprasidone (and all other second generation antipsychotics (SGAs)) received a boxed warning in the US due to increased mortality in elderly people with dementia-related psychosis.[2]
Sleepiness and headache are very common adverse effects (>10%).[6][7]
Common adverse effects (1–10%), include producing too much saliva or having dry mouth, runny nose, respiratory disorders or coughing, nausea and vomiting, stomach aches, constipation or diarrhea, loss of appetite, weight gain (but the smallest risk for weight gain compared to other antipsychotics[8]), rashes, fast heart beats, blood pressure falling when standing up quickly, muscle pain, weakness, twitches, dizziness, and anxiety.[6][7] Extrapyramidal symptoms are also common and include tremor, dystonia (sustained or repetitive muscle contractions), akathisia (the feeling of a need to be in motion), parkinsonism, and muscle rigidity; in a 2013 meta-analysis of 15 antipsychotic drugs, ziprasidone ranked 8th for such side effects.[14]
Ziprasidone is known to trigger mania in some bipolar patients.[15][16][17]
This medication can cause birth defects, according to animal studies, although this side effect has not been confirmed in humans.[2]
Recently, the FDA required the manufacturers of some atypical antipsychotics to include a warning about the risk of hyperglycemia and Type II diabetes with atypical antipsychotics. Some evidence suggests that ziprasidone does not cause insulin resistance to the degree of other atypical antipsychotics, such as olanzapine. Weight gain is also less of a concern with ziprasidone compared to other atypical antipsychotics.[18][19][20][21] In fact, in a trial of long term therapy with ziprasidone, overweight patients (BMI > 27) actually had a mean weight loss overall.[2] According to the manufacturer insert, ziprasidone caused an average weight gain of 2.2 kg (4.8 lbs), which is significantly lower than other atypical antipsychotics, making this medication better for patients that are concerned about their weight. In December 2014, the FDA warned that ziprasidone could cause a potentially fatal skin reaction, Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), although this was believed to occur only rarely.[22]
Discontinuation
[edit]The British National Formulary recommends a gradual withdrawal when discontinuing antipsychotics to avoid acute withdrawal syndrome or rapid relapse.[23] Symptoms of withdrawal commonly include nausea, vomiting, and loss of appetite.[24] Other symptoms may include restlessness, increased sweating, and trouble sleeping.[24] Less commonly there may be a feeling of the world spinning, numbness, or muscle pains.[24] Symptoms generally resolve after a short period of time.[24]
There is tentative evidence that discontinuation of antipsychotics can result in psychosis.[25] It may also result in reoccurrence of the condition that is being treated.[26] Rarely tardive dyskinesia can occur when the medication is stopped.[24]
Pharmacology
[edit]Pharmacodynamics
[edit]| Site | Ki (nM) | Action | Ref | |
|---|---|---|---|---|
| SERT | 112 | Blocker | [27] | |
| NET | 44 | Blocker | [27] | |
| DAT | 10000+ | ND | [27] | |
| 5-HT1A | 2.5–76 | Partial agonist | [28][29][30] | |
| 5-HT1B | 0.99–4.0 | Partial agonist | [29][27] | |
| 5-HT1D | 5.1–9.0 | Partial agonist | [29][27] | |
| 5-HT1E | 360–1279 | ND | [29][27] | |
| 5-HT2A | 0.08–1.4 | Antagonist | [31][28][29] | |
| 5-HT2B | 27.2 | Antagonist | [27] | |
| 5-HT2C | 0.72–13 | Antagonist | [28] | |
| 5-HT3 | 10000+ | ND | [27] | |
| 5-HT5A | 291 | ND | [27] | |
| 5-HT6 | 61–76 | Antagonist | [30][28] | |
| 5-HT7 | 6.0–9.3 | Antagonist | [27][30][28] | |
| α1A | 18 | Antagonist | [27][30] | |
| α1B | 9.0 | Antagonist | [27] | |
| α2A | 160 | Antagonist | [27][29][30] | |
| α2B | 48 | Antagonist | [27][29][30] | |
| α2C | 59–77 | Antagonist | [27][29][30] | |
| β1 | 2570+ | ND | [29][27] | |
| β2 | 10000+ | ND | [29][27] | |
| D1 | 30–130 | ND | [27][28] | |
| D2 | 4.8 | Antagonist | [32][28][30] | |
| D2L | 4.6 | Antagonist | [29][33] | |
| D2S | 4.2 | Antagonist | [29] | |
| D3 | 7.2 | Antagonist | [32][28][29] | |
| D4 | 0.8–105 | Antagonist | [32][28][27] | |
| D4.2 | 28–39 | Antagonist | [33] | |
| D4.4 | 14.9 | Antagonist | [34] | |
| D5 | 152 | ND | [27] | |
| H1 | 15–130 | Antagonist | [29][28][27] | |
| H2 | 3500+ | ND | [27] | |
| H3 | 10000+ | ND | [27] | |
| H4 | 10000+ | ND | [27] | |
| M1 | 300+ | ND | [35][27][28] | |
| M2 | 3000+ | ND | [35][27] | |
| M3 | 1300+ | ND | [35][30][27] | |
| M4 | 1600+ | ND | [35][27] | |
| M5 | 1600+ | ND | [35][27] | |
| σ1 | 110 | ND | [29] | |
| σ2 | ND | ND | ND | |
| Opioid | 1000+ | ND | [29] | |
| nACh | 10000+ | ND | [27] | |
| NMDA (PCP) |
10000+ | ND | [27] | |
| VDCC | 10000+ | ND | [27][29] | |
| VGSC | 2620 | ND | [29] | |
| hERG | 169 | Blocker | [36] | |
| Values are Ki (nM). The smaller the value, the more strongly the drug binds to the site. All data are for human cloned proteins, except H3 (guinea pig), σ1 (guinea pig), opioid (rodent), NMDA/PCP (rat), VDCC, and VGSC.[27] | ||||
Correspondence to clinical effects
[edit]Ziprasidone mostly affects the receptors of dopamine (D2), serotonin (5-HT2A, partially 5-HT1A, 5-HT2C, and 5-HT1D)[3][37][38] and epinephrine/norepinephrine (α1) to a high degree, while of histamine (H1) - moderately.[39][40] It also somewhat inhibits reuptake of serotonin and norepinephrine, though not dopamine.[39][41]
Ziprasidone's efficacy in treating the positive symptoms of schizophrenia is believed to be mediated primarily via antagonism of the dopamine receptors, specifically D2. Blockade of the 5-HT2A receptor may also play a role in its effectiveness against positive symptoms, though the significance of this property in antipsychotic drugs is still debated among researchers.[42] Blockade of 5-HT2A and 5-HT2C and activation of 5-HT1A as well as inhibition of the reuptake of serotonin and norepinephrine may all contribute to its ability to alleviate negative symptoms.;[43] however, its effects on the 5-HT1A receptor may be limited as a study[44] found ziprasidone would likely "produce detectable occupancy [of 5-HT1A receptors] only at higher doses that would produce unacceptable levels of side effects in man, although lower doses are sufficient to produce pharmacological effects." The relatively weak antagonistic actions of ziprasidone on the α1-adrenergic receptor likely in part explains some of its side effects, such as orthostatic hypotension. Unlike many other antipsychotics, ziprasidone has no significant affinity for the mACh receptors, and as such lacks any anticholinergic side effects. Like most other antipsychotics, ziprasidone is sedating due primarily to serotonin and dopamine blockade.[45][46]
Pharmacokinetics
[edit]The systemic bioavailability of ziprasidone is 100% when administered intramuscularly and 60% when administered orally without food.[3]
After a single dose intramuscular administration, the peak serum concentration typically occurs at about 60 minutes after the dose is administered, or earlier.[47] Steady state plasma concentrations are achieved within one to three days. Exposure increases in a dose-related manner and following three days of intramuscular dosing, little accumulation is observed.
The bioavailability of the drug is reduced by approximately 50% if a meal is not eaten before Ziprasidone ingestion.[2][48]
Ziprasidone is hepatically metabolized by aldehyde oxidase; minor metabolism occurs via cytochrome P450 3A4 (CYP3A4).[49] Medications that induce (e.g. carbamazepine) or inhibit (e.g. ketoconazole) CYP3A4 have been shown to decrease and increase, respectively, blood levels of ziprasidone.[50][51]
Its biological half-life time is 10 hours at doses of 80–120 milligrams.[4]
History
[edit]Ziprasidone is chemically similar to risperidone,[52] of which it is a structural analogue.[53] It was first synthesized in 1987 at the Pfizer central research campus in Groton, Connecticut.[54]
Phase I trials started in 1995.[55] In 1998 ziprasidone was approved in Sweden.[56][57] After the FDA raised concerns about long QT syndrome, more clinical trials were conducted and submitted to the FDA, which approved the drug on February 5, 2001.[55][58][59]
Society and culture
[edit]Lawsuit
[edit]In September 2009, the U.S. Justice Department announced that Pfizer had been ordered to pay a historic fine of $2.3 billion as a penalty for fraudulent marketing of several drugs, including Geodon.[60]
Brand names
[edit]In the US, Geodon is marketed by Viatris after Upjohn was spun off from Pfizer.[61][62][63]
Research
[edit]Ziprasidone has been studied in and reported to be effective in the treatment of borderline personality disorder, but findings are mixed.[64][65][66][67]
References
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- ^ "Justice Department Announces Largest Health Care Fraud Settlement in Its History". justice.gov. September 2, 2009. Retrieved October 6, 2016.
- ^ "Pfizer Completes Transaction to Combine Its Upjohn Business with Mylan". Pfizer. November 16, 2020. Retrieved June 17, 2024 – via Business Wire.
- ^ "Geodon". Pfizer. Retrieved June 17, 2024.
- ^ "Brands". Viatris. November 16, 2020. Retrieved June 17, 2024.
- ^ Del Casale A, Bonanni L, Bargagna P, Novelli F, Fiaschè F, Paolini M, et al. (2021). "Current Clinical Psychopharmacology in Borderline Personality Disorder". Curr Neuropharmacol. 19 (10): 1760–1779. doi:10.2174/1570159X19666210610092958. PMC 8977633. PMID 34151763.
Ziprasidone. This atypical antipsychotic has an affinity with serotonin 5HT2A, 5HT1B, and dopamine D2 receptors [31]. Ziprasidone at a daily dose of 80 mg for the treatment of BPD patients proved to be effective in the control of anger, paranoid ideation, impulsivity, and emotional instability, but not for anxiety and depressive symptoms [62]. The use of ziprasidone (daily dose range of 40–160 mg) could be considered for managing acute cases of BPD, considering the reported improvements of suicidal and self-injurious risk, hostility and aggression, impulse control, and severe anxious depressive symptoms [63].
- ^ Stoffers J, Völlm BA, Rücker G, Timmer A, Huband N, Lieb K (June 2010). "Pharmacological interventions for borderline personality disorder". Cochrane Database Syst Rev (6) CD005653. doi:10.1002/14651858.CD005653.pub2. PMC 4169794. PMID 20556762.
- ^ Pascual JC, Soler J, Puigdemont D, Pérez-Egea R, Tiana T, Alvarez E, et al. (April 2008). "Ziprasidone in the treatment of borderline personality disorder: a double-blind, placebo-controlled, randomized study". J Clin Psychiatry. 69 (4): 603–608. doi:10.4088/jcp.v69n0412. PMID 18251623.
- ^ Pascual JC, Oller S, Soler J, Barrachina J, Alvarez E, Pérez V (September 2004). "Ziprasidone in the acute treatment of borderline personality disorder in psychiatric emergency services". J Clin Psychiatry. 65 (9): 1281–1282. doi:10.4088/jcp.v65n0918b. PMID 15367057.
Further reading
[edit]- Taylor D (2006). Schizophrenia in Focus. Pharmaceutical Press. p. 123. ISBN 978-0-85369-607-0. Retrieved May 13, 2012.
Ziprasidone
View on GrokipediaMedical Uses
Indications
Ziprasidone is approved by the U.S. Food and Drug Administration (FDA) for the treatment of schizophrenia in adults, encompassing both acute exacerbations and maintenance therapy to prevent relapse. It is also indicated for the acute treatment of manic or mixed episodes associated with bipolar I disorder, with or without psychotic features, as monotherapy in adults. Additionally, the oral formulation supports maintenance treatment of bipolar I disorder as an adjunct to lithium or valproate in adults, reducing the risk of mood episode recurrence. The intramuscular formulation is specifically approved for the acute treatment of agitation in adult patients with schizophrenia who require short-term management with an injectable antipsychotic. Clinical trials have demonstrated ziprasidone's efficacy in schizophrenia, with pivotal placebo-controlled studies showing significant reductions in both positive and negative symptoms. In short-term trials, ziprasidone at doses of 80 mg/day and 160 mg/day produced greater improvements in Positive and Negative Syndrome Scale (PANSS) total scores compared to placebo, with mean reductions of approximately 20-25 points versus 10-15 points for placebo, corresponding to response rates of 30-40% versus 15-20%.[2] For negative symptoms, ziprasidone showed superior PANSS negative subscale improvements over placebo (p < 0.05) in a 1-year double-blind trial.[3] In bipolar mania, three-week placebo-controlled trials reported significant mood stabilization, with ziprasidone reducing Young Mania Rating Scale (YMRS) total scores by a least squares mean of -17.0 points compared to -9.5 points for placebo (p < 0.001), alongside improvements in positive psychotic symptoms on the PANSS.[4] Off-label uses of ziprasidone include adjunctive therapy for major depressive disorder (MDD), particularly in cases with partial response to antidepressants, though evidence is mixed and primarily from small randomized trials. In an 8-week double-blind study, adjunctive ziprasidone (40-160 mg/day) added to escitalopram significantly improved Montgomery-Åsberg Depression Rating Scale (MADRS) scores versus placebo in adults with MDD (p = 0.015), but benefits were not consistent for cognitive symptoms.[5] For treatment-resistant depression, augmentation with ziprasidone has shown increased response rates (number needed to treat = 7) in meta-analyses of trials, yet with limitations including higher risks of adverse events like akathisia.[6] In autism spectrum disorder, ziprasidone is used off-label for irritability, with naturalistic studies in youth reporting reductions in aberrant behavior checklist-irritability subscale scores (mean decrease of 50-60%) at doses of 20-80 mg/day, but evidence is limited to open-label and retrospective designs without robust placebo controls, and long-term safety data are sparse.[7]Dosage and Administration
Ziprasidone is available in oral capsule formulations of 20 mg, 40 mg, 60 mg, and 80 mg strengths, as well as an intramuscular (IM) injection in 20 mg/mL single-dose vials.[8] For schizophrenia, the recommended initial oral dose is 20 mg twice daily with food, with titration in increments of no more than 20 mg per day to a target range of 40 mg to 80 mg twice daily (80-160 mg/day total), based on clinical response and tolerability; the maximum recommended dose is 80 mg twice daily.[8] For acute agitation associated with schizophrenia, the IM dose is 10 mg injected every 2 hours or 20 mg every 4 hours as needed, not to exceed 40 mg per day, with IM use limited to no more than 3 consecutive days before transitioning to oral therapy.[8] In bipolar I disorder with acute manic or mixed episodes, oral dosing begins at 40 mg twice daily on day 1, increasing to 60 mg to 80 mg twice daily on day 2 if tolerated, with a maintenance range of 40-80 mg twice daily.[8] Oral capsules must be taken with food (approximately 500 calories), as this increases bioavailability by up to twofold compared to the fasting state, which is essential for achieving therapeutic plasma levels.[8] Capsules should be swallowed whole without splitting, chewing, or crushing.[8] For IM administration, the vial must be reconstituted with 1.2 mL of sterile water for injection to yield 20 mg/mL, intended solely for intramuscular use and not for intravenous administration; any unused portion after reconstitution should be discarded.[8] Monitoring includes a baseline electrocardiogram (ECG) to assess QT interval prolongation risk, with periodic ECGs recommended thereafter, particularly in patients with cardiac risk factors; serum potassium and magnesium levels should also be checked in at-risk individuals.[8] Additionally, baseline and follow-up assessments of weight, fasting lipid profile, and fasting blood glucose are advised at 3 months and annually, in line with guidelines for atypical antipsychotics.[1] Dose adjustments are recommended for elderly patients, starting at the lower end of the dosing range (e.g., 20 mg daily or less) with slower titration and closer monitoring due to increased sensitivity.[8] No oral dose adjustment is needed for mild to moderate hepatic or renal impairment, though caution is advised for IM use in severe renal impairment due to the sulfobutyl ether beta-cyclodextrin excipient; in hepatic cirrhosis, exposure may increase, warranting careful titration.[8] Concomitant use of strong CYP3A4 inhibitors (e.g., ketoconazole 400 mg/day) increases ziprasidone AUC and Cmax by approximately 35-40%; no dose adjustment is recommended, but monitor closely for adverse effects.[8]Contraindications and Precautions
Contraindications
Ziprasidone is contraindicated in patients with a known hypersensitivity to the drug or any of its components, as severe allergic reactions may occur upon exposure.[9] Due to its dose-dependent prolongation of the QT interval, which increases the risk of serious ventricular arrhythmias such as torsades de pointes, ziprasidone must not be administered to individuals with a known history of QT prolongation (including congenital long QT syndrome), recent acute myocardial infarction, or uncompensated heart failure.[9] Concurrent use with other medications that prolong the QT interval is also absolutely contraindicated to prevent additive effects; examples include antiarrhythmics like dofetilide and quinidine, antipsychotics such as thioridazine and pimozide, and antibiotics including moxifloxacin and sparfloxacin.[9] Ziprasidone is contraindicated in patients who are taking monoamine oxidase inhibitors (MAOIs), including linezolid and intravenous methylene blue, or who have taken MAOIs within 14 days, because of the risk of serotonin syndrome.[9] The U.S. Food and Drug Administration (FDA) prescribing information for ziprasidone includes a black box warning highlighting the increased risk of death in elderly patients with dementia-related psychosis treated with antipsychotic medications, emphasizing the need to avoid use in this population due to heightened cardiac and other vulnerabilities.[9] To mitigate these risks, patient screening prior to initiation should include a detailed allergy history to rule out hypersensitivity and a baseline electrocardiogram (ECG) to evaluate QT interval and identify underlying cardiac conditions.[1]Warnings and Special Populations
Ziprasidone carries a boxed warning for increased mortality in elderly patients with dementia-related psychosis, with analyses of placebo-controlled trials showing a 1.6-1.7 times higher risk of death compared to placebo, primarily due to cardiovascular or infectious causes; it is not approved for this indication. In geriatric patients without dementia, no overall differences in safety were observed, but greater sensitivity may necessitate a lower starting dose and slower titration. For hepatic impairment, exposure increases modestly (AUC by 13% in Child-Pugh A and 34% in Child-Pugh B), but no specific dose adjustment is recommended; caution is advised in severe cases (Child-Pugh C) due to limited data. In renal impairment, pharmacokinetics are minimally affected for oral formulations since less than 1% is excreted unchanged in urine, though the intramuscular form requires caution due to the sulfobutyl ether beta-cyclodextrin excipient, which may accumulate in patients with creatinine clearance below 50 mL/min. Dose reductions may be considered in these populations based on tolerability. Animal reproduction studies have shown that ziprasidone may cause developmental toxicity, including possible teratogenic effects; there are no adequate and well-controlled studies in humans. Limited data from pregnancy exposure registries involving over 1800 cases suggest no increased risk of major birth defects. Third-trimester exposure may cause neonatal extrapyramidal symptoms or withdrawal.[10] Pregnant patients should be advised of potential risks, use effective contraception if appropriate, monitor neonates closely, and enroll in the National Pregnancy Registry for Atypical Antipsychotics. During lactation, ziprasidone is present in breast milk in low amounts; breastfeeding is not recommended, or infants should be monitored for sedation, irritability, poor feeding, or extrapyramidal symptoms if continued.[1] Pediatric use of ziprasidone is not approved by the FDA for patients under 18 years, as safety and efficacy have not been established; off-label use in adolescents requires careful risk-benefit assessment due to potential for metabolic and neurological effects. Additional warnings include risks of hyperglycemia and new-onset diabetes, particularly in patients with predisposing factors, as well as dyslipidemia and weight gain, which may contribute to metabolic syndrome; neuroleptic malignant syndrome, a potentially fatal reaction involving hyperthermia and rigidity; tardive dyskinesia, with higher risk from prolonged use; and increased suicidality in young adults aged 18-24 during initial treatment. Patients at elevated suicide risk should receive close supervision and the smallest effective prescription quantity. Monitoring protocols for special populations emphasize baseline and periodic assessments: metabolic screening including fasting glucose, lipids, and weight at baseline, 3 months, and annually thereafter (or every 3-6 months initially if high-risk); electrolytes in those with predisposing factors; and close observation for NMS or tardive dyskinesia signs.[11]Adverse Effects and Safety
Common Adverse Effects
Common adverse effects of ziprasidone, observed in placebo-controlled clinical trials, primarily include somnolence, dizziness, and nausea, which occur at rates exceeding 10% in patients with schizophrenia or bipolar mania. In short-term trials for schizophrenia, somnolence affected 14% of ziprasidone-treated patients compared to 7% on placebo, dizziness occurred in 8% versus 6%, and nausea in 10% versus 7%. For bipolar mania, these rates were higher for somnolence (31% versus 12%) and dizziness (16% versus 7%), with nausea remaining at 10% versus 7%. These effects are generally mild and manageable, often leading to discontinuation in fewer than 5% of cases. Gastrointestinal disturbances are also frequent, with dyspepsia reported in 8% of schizophrenia patients (versus 7% placebo) and constipation in 9% (versus 8%). These symptoms, along with nausea, may relate briefly to ziprasidone's serotonin receptor antagonism. Neurological effects include extrapyramidal symptoms (EPS), such as akathisia, at lower rates than typical antipsychotics; akathisia incidence was 8% in schizophrenia trials (versus 7% placebo) and 10% in bipolar trials (versus 5%). Orthostatic hypotension, manifesting as lightheadedness, occurred in about 5% of intramuscular administration cases. Other common effects include rhinitis (4%) and headache (>10%).[1] Ziprasidone is associated with minimal weight gain compared to other atypical antipsychotics, with a median increase of 0.5 kg in short-term trials and only 10% of schizophrenia patients experiencing a ≥7% body weight increase (versus 4% placebo). In the CATIE study of chronic schizophrenia, ziprasidone was weight-neutral and showed favorable metabolic effects, with no significant increases in weight or lipids. Most adverse effects peak within the first few weeks of treatment and often resolve with continued use, dose adjustment, or supportive measures; incidence data derive from placebo-controlled trials involving thousands of patients across schizophrenia and bipolar populations.[12]| Adverse Effect | Incidence in Schizophrenia Trials (Ziprasidone vs. Placebo) | Incidence in Bipolar Mania Trials (Ziprasidone vs. Placebo) |
|---|---|---|
| Somnolence | 14% vs. 7% | 31% vs. 12% |
| Dizziness | 8% vs. 6% | 16% vs. 7% |
| Nausea | 10% vs. 7% | 10% vs. 7% |
| Dyspepsia | 8% vs. 7% | Not ≥2% difference |
| Constipation | 9% vs. 8% | Not ≥2% difference |
| Akathisia | 8% vs. 7% | 10% vs. 5% |
| Weight Gain (≥7%) | 10% vs. 4% | 2.4–4.4% vs. 1.8% |
Serious Adverse Effects
Ziprasidone, an atypical antipsychotic, is associated with several serious adverse effects that require careful monitoring, particularly in vulnerable patients. These include potentially life-threatening cardiovascular, metabolic, neurological, hematologic, and other events, with incidences generally low but significant enough to warrant precautions. Severe cutaneous adverse reactions, including Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) and Stevens-Johnson syndrome, have been reported; immediate discontinuation is recommended if suspected.[8][8] Cardiovascular risks are prominent, primarily involving QTc interval prolongation due to blockade of the hERG potassium channel, which can lead to torsades de pointes and sudden cardiac death in predisposed individuals. Clinical trials showed an average QTc increase of about 10 ms at doses up to 160 mg/day, with 0.06% of patients experiencing QTc exceeding 500 ms; the risk of torsades de pointes remains below 1%. Post-marketing reports have documented rare cases of ventricular arrhythmias and sudden death, particularly in patients with risk factors such as bradycardia, hypokalemia, hypomagnesemia, congenital long QT syndrome, recent myocardial infarction, uncompensated heart failure, or concurrent use of QT-prolonging drugs. Female sex further elevates this risk. Baseline ECG and periodic monitoring of QTc, serum electrolytes, and avoidance of contraindicated agents are recommended.[8][1] Metabolic disturbances include new-onset diabetes mellitus and dyslipidemia, which can contribute to long-term morbidity. Hyperglycemia leading to diabetic ketoacidosis or hyperosmolar coma has been reported, with approximately 1-2% incidence of new-onset diabetes in treated populations, higher in those with obesity or family history. Dyslipidemia manifests as elevated triglycerides (e.g., ≥50 mg/dL increase in about 34% of schizophrenia patients in trials) and cholesterol changes. Monitoring of fasting glucose and lipid profiles at baseline and periodically, especially in at-risk patients, is advised to detect these effects early.[8][13] Neurological serious effects encompass neuroleptic malignant syndrome (NMS) and seizures. NMS, a rare but potentially fatal reaction occurring in less than 0.1% of cases, presents with hyperpyrexia, muscle rigidity, altered mental status, and autonomic instability; immediate discontinuation and supportive care are essential. Seizures have been observed in 0.1-0.4% of patients, necessitating caution in those with a history of epilepsy or conditions lowering the seizure threshold.[8][1] Hematologic adverse effects such as leukopenia and agranulocytosis are rare but serious, potentially leading to severe infections. These require frequent complete blood count monitoring, particularly in the first few months or in patients with pre-existing low white blood cell counts or prior drug-induced leukopenia; discontinuation is indicated if absolute neutrophil count falls below 1000/mm³ without other etiology.[8][1] Other notable risks include suicidal ideation, particularly in younger patients with psychotic or bipolar disorders, and priapism, a rare urologic emergency reported in isolated cases. Close supervision of high-risk individuals for worsening depression or suicidality, along with the smallest effective prescription quantity, is crucial. The FDA has issued a black box warning highlighting a 1.6-1.7-fold increased mortality risk (primarily from cardiovascular or infectious causes) in elderly patients with dementia-related psychosis treated with ziprasidone, and it is not approved for this indication.[8][1]Discontinuation Effects
Discontinuation of ziprasidone, an atypical antipsychotic, can lead to withdrawal symptoms due to dopaminergic supersensitivity and rapid offset of its effects, given its relatively short half-life of approximately 7 hours.[1] Common withdrawal phenomena include rebound psychosis, insomnia, nausea, and anxiety, which may emerge as a result of abrupt cessation rather than relapse of the underlying condition.[14] In specific cases, such as dose reductions or sudden stops, patients have experienced akathisia characterized by intense motor restlessness and an urge to move.[15] These symptoms typically onset within 1-4 days after discontinuation and last 1-2 weeks, though motor effects like akathisia can resolve faster with symptomatic treatment.[15][16] To minimize risks, tapering ziprasidone is recommended over 1-4 weeks for short-term use, with slower reductions (e.g., over several months) for patients on long-term therapy exceeding 6 months, allowing time for receptor adaptations to normalize.[14] This approach involves gradual dose decreases, such as 20-25% every few days initially, monitored closely for emerging symptoms, as no standardized protocol exists specifically for ziprasidone but general antipsychotic guidelines emphasize individualized hyperbolic tapering to maintain low D2 receptor occupancy.[17][18] Risk factors for significant discontinuation effects include abrupt cessation, high doses (e.g., >80 mg/day), and prolonged therapy, which heighten the likelihood of supersensitivity psychosis or movement disorders.[14] Observational studies on atypical antipsychotics indicate that 20-30% of patients experience mild withdrawal symptoms like anxiety or insomnia with abrupt stops, compared to under 5% with proper tapering, though data specific to ziprasidone are limited to case reports.[19] For instance, a case report documented rapid-onset psychosis in an adolescent female after abrupt ziprasidone termination, resolving upon reinitiation, highlighting vulnerability in younger patients.[16] If relapse or severe withdrawal occurs, reinitiation of ziprasidone at a low dose with rapid titration is advised, often leading to symptom resolution within days, as seen in reported cases of akathisia and psychosis.[15][16] Close clinical monitoring is essential during this process to differentiate withdrawal from disease recurrence.[14]Overdose
Symptoms and Signs
Ziprasidone overdose typically presents with central nervous system depression, manifesting as somnolence or drowsiness, which is the most commonly reported acute symptom.[20][21] Other early signs include slurred speech, tremor, anxiety, and extrapyramidal symptoms such as uncontrollable shaking or sudden involuntary movements.[20][21] The clinical presentation is often dose-dependent, with mild overdoses (approximately 100-500 mg) primarily causing sedation and mild gastrointestinal upset like vomiting or diarrhea.[22][23] In severe cases exceeding 1000 mg, more serious effects emerge, including hypotension, tachycardia, QTc interval prolongation (often >500 ms), seizures, and progression to coma.[22][23][1] Vital sign abnormalities in overdose frequently involve cardiovascular instability, such as tachycardia (heart rate >100 bpm), alongside hypotension that may require intervention.[22][23] Prolonged QTc intervals represent a critical risk, potentially leading to torsades de pointes, though this arrhythmia is uncommon in isolated ziprasidone ingestions.[1][23] Neurologically, patients may exhibit agitation, exacerbation of extrapyramidal symptoms (e.g., dystonia or akathisia), and in severe overdoses, respiratory depression or fluctuating mental status progressing to unresponsiveness.[20][22] Miosis is also observed, likely due to alpha-1 adrenergic receptor antagonism.[23] Fatalities from ziprasidone overdose are rare and typically occur in the context of polypharmacy, such as concurrent use of alcohol, opioids, benzodiazepines, or other sedatives, which exacerbate respiratory depression and hemodynamic instability; isolated ingestions seldom result in death.[22][24] For instance, case reports describe survival after ingestions up to 4480 mg when co-ingestants were present but managed promptly, underscoring the role of multiple agents in adverse outcomes.[24][22]Management and Treatment
Management of ziprasidone overdose primarily involves supportive care, with no specific antidote available. Initial assessment should prioritize the ABCs—airway, breathing, and circulation—to stabilize the patient, including establishing intravenous access and ensuring adequate ventilation, with intubation considered if respiratory compromise occurs.[22] Gastrointestinal decontamination with activated charcoal is recommended if ingestion occurred within 1 to 2 hours and the patient is alert or intubated, though gastric lavage is rarely performed and reserved for cases with large recent ingestions in unprotected airways.[1] Cardiac monitoring is essential due to the risk of QT interval prolongation and arrhythmias; continuous electrocardiogram (ECG) surveillance should be instituted upon presentation, with serial ECGs to assess for torsades de pointes. If QT prolongation is detected, intravenous magnesium sulfate (typically 1 to 2 g diluted and infused over 5 to 60 minutes, repeatable if necessary) is administered to mitigate arrhythmia risk, while avoiding concomitant use of other QT-prolonging agents such as certain antiarrhythmics or antibiotics.[1][25][26] Symptomatic treatments address specific manifestations, including benzodiazepines (e.g., lorazepam or diazepam) for agitation or seizures, and intravenous fluids or vasopressors for hypotension unresponsive to initial resuscitation.[22] Enhanced elimination techniques like hemodialysis are ineffective owing to ziprasidone's high protein binding (>99%), which limits dialyzability, as influenced by its pharmacokinetic profile of extensive hepatic metabolism and low renal excretion.[20] For disposition, patients with severe features such as arrhythmias, coma, or hemodynamic instability require intensive care unit admission for close monitoring, while those with mild symptoms may be observed for 24 to 48 hours in a general ward, as delayed effects are uncommon beyond 6 to 12 hours post-ingestion.[27] Data from U.S. Poison Control Centers (2000–2014) indicate favorable outcomes with these supportive measures, reporting 12,587 single-substance ziprasidone exposures with only 9 deaths, yielding a mortality rate of less than 0.1%.[28]Pharmacology
Pharmacodynamics
Ziprasidone is an atypical antipsychotic that exerts its effects primarily through antagonism at dopamine D₂ and serotonin 5-HT₂A receptors, with additional activity at other receptors. It demonstrates high binding affinity for the dopamine D₂ receptor (Kᵢ = 4.8 nM, antagonist), D₃ receptor (Kᵢ = 7.2 nM, antagonist), serotonin 5-HT₂A receptor (Kᵢ = 0.4 nM, antagonist), 5-HT₁D receptor (Kᵢ = 2 nM, antagonist), and serotonin 5-HT₂C receptor (Kᵢ = 1.3 nM, antagonist), as well as the serotonin 5-HT₁A receptor (Kᵢ = 3.4 nM, partial agonist), along with moderate affinity for the α₁-adrenergic receptor (Kᵢ = 10 nM, antagonist) and histamine H₁ receptor (Kᵢ = 47 nM, antagonist).[8][29] Ziprasidone also inhibits reuptake at serotonin (IC₅₀ ≈ 29 nM) and norepinephrine (IC₅₀ ≈ 160 nM) transporters, contributing to potential antidepressant and anxiolytic effects, with no significant affinity for the dopamine transporter (IC₅₀ >10,000 nM).[8][30] In the treatment of schizophrenia, ziprasidone's antagonism of D₂ receptors in the mesolimbic pathway reduces positive symptoms such as hallucinations and delusions by modulating excessive dopaminergic activity.[1] Concurrent antagonism at 5-HT₂A receptors enhances dopaminergic and serotonergic transmission in the prefrontal cortex, contributing to improvements in negative symptoms like social withdrawal and cognitive deficits.[31] The partial agonism at 5-HT₁A receptors may further support antipsychotic efficacy by promoting serotonin release and reducing anxiety-related symptoms.[1] For bipolar disorder, ziprasidone's modulation of serotonin receptors, particularly through 5-HT₂A antagonism and 5-HT₁A partial agonism, is thought to stabilize mood during manic episodes by balancing serotonergic tone and indirectly influencing dopaminergic pathways.[31] This receptor profile underpins its antimanic effects, though the exact mechanisms remain partially understood beyond established clinical efficacy.[32] Adverse effects of ziprasidone are linked to its broader receptor interactions; H₁ receptor antagonism contributes to sedation and somnolence, while α₁-adrenergic blockade can cause orthostatic hypotension.[32] The drug's relatively low risk of extrapyramidal symptoms (EPS) is attributed to modest D₂ receptor occupancy of approximately 50-70% at therapeutic doses (e.g., 80-160 mg/day), which avoids excessive striatal blockade compared to typical antipsychotics.[33][34] Additionally, despite 5-HT₂C antagonism—which is associated with weight gain in some antipsychotics—ziprasidone exhibits minimal metabolic impact, possibly due to its balanced serotonin-dopamine profile and reuptake inhibition properties.[35]| Receptor | Affinity (Kᵢ, nM) | Activity | Linked Clinical Outcome |
|---|---|---|---|
| D₂ | 4.8 | Antagonist | Reduces positive symptoms in schizophrenia; modest occupancy (50-70%) limits EPS risk[33] |
| D₃ | 7.2 | Antagonist | May contribute to efficacy against negative symptoms and cognitive deficits[8] |
| 5-HT₂A | 0.4 | Antagonist | Improves negative and cognitive symptoms; contributes to mood stabilization in bipolar disorder[1] |
| 5-HT₁A | 3.4 | Partial Agonist | Enhances antipsychotic and antimanic effects via serotonin modulation[31] |
| 5-HT₂C | 1.3 | Antagonist | Associated with low weight gain liability despite antagonism[35] |
| 5-HT₁D | 2 | Antagonist | Potential role in modulating serotonergic tone[8] |
| α₁ | 10 | Antagonist | Orthostatic hypotension[32] |
| H₁ | 47 | Antagonist | Sedation and somnolence[32] |