Granisetron Injection and Ziprasidone: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Ziprasidone
Granisetron Injection
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Increased risk of QT interval prolongation and an increased risk of serotonin syndrome (hypertension, hyperthermia, myoclonus, mental status changes)
Interaction Deep Dive
The concomitant use of ziprasidone with other drugs that prolong the QT interval is contraindicated due to additive risks for QT interval prolongation. Serotonin syndrome has also been reported with ziprasidone monotherapy and in combination with other serotonergic drugs. Signs and symptoms may include mental status changes (eg., agitation, hallucinations, delirium, and coma), autonomic instability (eg., tachycardia, labile blood pressure, dizziness, diaphoresis, flushing, hyperthermia), neuromuscular symptoms (eg., tremor, rigidity, myoclonus, hyperreflexia, incoordination), seizures, and gastrointestinal symptoms (eg., nausea, vomiting, diarrhea). Monitor all patients taking ziprasidone for the emergence of serotonin syndrome. Discontinue treatment with ziprasidone and any concomitant serotonergic agents immediately if the above symptoms occur, and initiate supportive symptomatic treatment. If concomitant use of ziprasidone with other serotonergic drugs is clinically warranted, inform patients of the increased risk of serotonin syndrome and monitor for symptoms12.
Why it happens (mechanism)
Additive QT interval prolongation; additive serotonergic effects
Literature reports
1 report — tap to read
a) A 30-year-old female patient developed serotonin syndrome after initiating sertraline for persistent depressive symptoms while also being treated with ziprasidone 40 mg/day. After discontinuing paroxetine for lack of response, sertraline was initiated at 50 mg/day and titrated to 125 mg/day over 4 weeks. Two days later, the patient developed severe anxiety, jerking movements of upper extremities, transient headaches, confusion, diaphoresis, hyperreflexia, and frequent myoclonus. Sertraline was discontinued, ziprasidone was decreased to 20 mg/day, and the patient was treated with IV fluids and clonazepam 0.5 mg twice daily; her symptoms resolved within 48 hours. Use of ziprasidone, a potent serotonin 5-hydroxytryptamine-1A receptor agonist, together with the increased inhibition of serotonin reuptake caused by the sertraline dose titration likely contributed to the development of serotonin syndrome in this case 3.
Common questions
Can I take Granisetron Injection and Ziprasidone together?
Increased risk of QT interval prolongation and an increased risk of serotonin syndrome (hypertension, hyperthermia, myoclonus, mental status changes) Always confirm with your pharmacist or prescriber before making any change.
How serious is the Granisetron Injection and Ziprasidone interaction?
It is rated contraindicated. These should generally not be used together.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Granisetron Injection or Ziprasidone need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (3)
- Product Information: GEODON(R) intramuscular injection, ziprasidone mesylate intramuscular injection. Viatris Specialty LLC(per FDA), Morgantown, WV, 2025.
- Product Information: GEODON(R) oral capsules, ziprasidone oral capsules. Viatris Specialty LLC(per FDA), Morgantown, WV, 2025. DailyMed
- Palekar N & Eisman J: Serotonin syndrome with ziprasidone and sertraline. J Neuropsychiatry Clin Neurosci 2013; 25(2):E1. PubMed
Keep reading about Ziprasidone
Keep reading about Granisetron Injection
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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
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