Ziprasidone

Adverse effects

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.

Sleepiness and headache are very common adverse effects (>10%).

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), rashes, fast heart beats, blood pressure falling when standing up quickly, muscle pain, weakness, twitches, dizziness, and anxiety. 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.

Ziprasidone is known to trigger mania in some bipolar patients.

This medication can cause birth defects, according to animal studies, although this side effect has not been confirmed in humans.

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. In fact, in a trial of long term therapy with ziprasidone, overweight patients (BMI > 27) actually had a mean weight loss overall. 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.

Discontinuation

The British National Formulary recommends a gradual withdrawal when discontinuing antipsychotics to avoid acute withdrawal syndrome or rapid relapse. Symptoms of withdrawal commonly include nausea, vomiting, and loss of appetite. Other symptoms may include restlessness, increased sweating, and trouble sleeping. Less commonly there may be a feeling of the world spinning, numbness, or muscle pains. Symptoms generally resolve after a short period of time.

There is tentative evidence that discontinuation of antipsychotics can result in psychosis. It may also result in reoccurrence of the condition that is being treated. Rarely tardive dyskinesia can occur when the medication is stopped.

Pharmacology

Pharmacodynamics

Correspondence to clinical effects

Ziprasidone mostly affects the receptors of dopamine (D₂), serotonin (5-HT_2A, partially 5-HT_1A, 5-HT_2C, and 5-HT_1D) and epinephrine/norepinephrine (α₁) to a high degree, while of histamine (H₁) - moderately. It also somewhat inhibits reuptake of serotonin and norepinephrine, though not dopamine.

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-HT_2A 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. Blockade of 5-HT_2A and 5-HT_2C and activation of 5-HT_1A as well as inhibition of the reuptake of serotonin and norepinephrine may all contribute to its ability to alleviate negative symptoms.; however, its effects on the 5-HT_1A receptor may be limited as a study found ziprasidone would likely "produce detectable occupancy [of 5-HT_1A 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.

It has also been identified as a potent vesicular monoamine transporter 2 (VMAT2) inhibitor (IC₅₀Tooltip half-maximal inhibitory concentration = 15 nM).

Pharmacokinetics

The systemic bioavailability of ziprasidone is 100% when administered intramuscularly and 60% when administered orally without food.

After a single dose intramuscular administration, the peak serum concentration typically occurs at about 60 minutes after the dose is administered, or earlier. 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.

Ziprasidone is hepatically metabolized by aldehyde oxidase; minor metabolism occurs via cytochrome P450 3A4 (CYP3A4). Medications that induce (e.g. carbamazepine) or inhibit (e.g. ketoconazole) CYP3A4 have been shown to decrease and increase, respectively, blood levels of ziprasidone.

Its biological half-life time is 10 hours at doses of 80–120 milligrams.

History

Ziprasidone is chemically similar to risperidone, of which it is a structural analogue. It was first synthesized in 1987 at the Pfizer central research campus in Groton, Connecticut.

Phase I trials started in 1995. In 1998 ziprasidone was approved in Sweden. 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.

Society and culture

Lawsuits

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.

Matthew Dougherty, a 51‑year‑old former teacher and artist with a diagnosis of schizophrenia, died on May 21, 2024, at Phoenixville Hospital in Phoenixville, Pennsylvania. According to a wrongful death lawsuit filed by his family in March 2025, Dougherty had been admitted to the hospital after a mental health crisis during which he was tased by police and suffered injuries. While hospitalized, Dougherty's regular psychiatric medications were discontinued. On the evening of his death, an alarm sounded in a nearby room, causing him to become agitated. Hospital staff called the police to restrain him, and responding officers again used a taser on Dougherty. Shortly afterward, nurses administered two doses of Geodon (ziprasidone) – a total of 40 mg, an amount the lawsuit equated to "administering poison". Minutes later, Dougherty went into cardiac arrest and could not be resuscitated. The lawsuit names as defendants Tower Health, which operates Phoenixville Hospital, and seeks damages for wrongful death and negligence. At the time the suit was filed, Tower Health had not filed a response to the complaint.

Brand names

In the US, Geodon is marketed by Viatris after Upjohn was spun off from Pfizer.

Research

Ziprasidone has been studied in and reported to be effective in the treatment of borderline personality disorder, but findings are mixed.