Drug Interaction Report

Zotepine and Dolasetron: Interaction Details

A pharmacist-reviewed analysis of the Zotepine and Dolasetron interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Dolasetron

Anzemet Anzemet®
+

Zotepine

No brand names on record
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Major
Potentially serious — often needs a change or close monitoring.
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.

Of 63 documented Zotepine interactions, 62 are rated major — including this one.
Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.
Onset
unspecified
Evidence
theoretical
Severity
Major

What happens

An increased risk of cardiotoxicity (QT prolongation, torsade de pointes, cardiac arrest)

Interaction Deep Dive

Several antipsychotic agents have demonstrated QT prolongation including haloperidol8, quetiapine 3, risperidone 9, sertindole 10, sultopride 11, and zotepine 12. Even though no formal drug interaction studies have been done, the coadministration of dolasetron and other drugs known to prolong the QTc interval, including antipsychotics, is not recommended 13.

Why it happens (mechanism)

Additive effects on QT prolongation

Literature reports

3 reports — tap to read

a) In several studies, dolasetron resulted in significant, dose-related increases in mean PR, QRS, and QTc intervals compared to baseline values. Measured changes in ECG parameters were transient, reversible, and asymptomatic. Increases in PR and QRS intervals may be due to prolongation of maximum upstroke velocity (Vmax) due to binding of dolasetron to fast sodium channels. The cause of QTc interval prolongation appears to be due to prolongation of the QRS interval, increases in heart rate, or both 421.

b) A total of 7 patients developed torsade de pointes after therapeutic use of haloperidol in high doses 56. Three patients developed the dysrhythmia after administration of 211 to 825 mg haloperidol over 1 to 2 days for agitated delirium. These 3 patients recovered from the initial episodes, but 1 patient subsequently died of cardiac arrest upon readministration of haloperidol. Four patients developed the dysrhythmia after administration of 170 to 580 mg over 1 to 4 days for delirium associated with bacterial meningitis (1), status asthmaticus (2) or respiratory insufficiency (1). All 4 patients recovered with no adverse sequelae.

c) Prolongation of the QTc interval was reported in 8 patients receiving risperidone 7.

Common questions

Can I take Zotepine and Dolasetron together?

An increased risk of cardiotoxicity (QT prolongation, torsade de pointes, cardiac arrest) Always confirm with your pharmacist or prescriber before making any change.

How serious is the Zotepine and Dolasetron interaction?

It is rated major. Potentially serious — often needs a change or close monitoring.

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 Zotepine or Dolasetron 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 (13)

  1. Kris MG, Grunberg SM, Gralla RJ, et al: Dose-ranging evaluation of the serotonin antagonist dolasetron mesylate in patients receiving high-dose cisplatin. J Clin Oncol 1994; 12:1045-1049. PubMed
  2. Hunt TL, Cramer M, Shah A, et al: A double-blind, placebo-controlled, dose-ranging safety evaluation of single-dose intravenous dolasetron in healthy male volunteers. J Clin Pharmacol 1995; 35:705-712. PubMed
  3. Owens R: Risk assessment for antimicrobial agent-induced QTc prolongation and torsades de pointes. Pharmacother 2001; 21(3):310-319.
  4. Product Information: Anzemet(R), dolasetron. Hoechst Marion Roussel, Kansas City, MO, 1997. DailyMed
  5. Metzger E & Friedman R: Prolongation of the corrected QT and torsade de pointes cardiac arrhythmia associated with intravenous haloperidol in the medically ill. J Clin Psychopharmacol 1993; 13:128-132.
  6. Wilt JL, Minnema AM, Johnson RF, et al: Torsade de pointes associated with the use of intravenous haloperidol. Ann Intern Med 1993; 119:391-394. PubMed
  7. Product Information: Risperdal(R) risperidone. Janssen Pharmaceutica, Titusville, NJ, 1999.
  8. O'Brien JM, Rockwood RP, & Suh KI: Haloperidol-induced torsade de pointes. Ann Pharmacother 1999; 33(10):1046-1050. DOI
  9. Duenas-Laita A, Castro-Villamor MA, Martin-Escudero JC, et al: New clinical manifestations of acute risperidone poisoning (letter). Clin Toxicol 1999; 37(7):893-894. PubMed
  10. Agelink MW, Zeit T, Baumann B, et al: In vivo cardiovascular effects of the new atypical neuroleptic sertindole. Int J Psychiatry Clin Pract 2001; 5:33-40. DOI
  11. Lande G, Drouin E, Gauthier C, et al: Arrhythmogenic effects of sultopride chlorhydrate: clinical and cellular electrophysiological correlation. Ann Fr Anesth Reanim 1992; 11:629-635.
  12. Sweetman S (Ed): Martindale: The Complete Drug Reference. London: Pharmaceutical Press. Electronic version, MICROMEDEX, Greenwood Village, Colorado, Edition expires 06/2003.
  13. Product Information: Anzemet(R), dolasetron. Hoechst Marion Roussel, Kansas City, MO, 1997. DailyMed
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Dolasetron

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Beyond drug–drug

These medications also interact with supplements

Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:

Dolasetron + Activated Charcoal Grapefruit Lithium St. John's Wort 1,3-dmaa 5-htp Acacia Rigidula Acetyl-l-carnitine + 161 more

major · moderate · minor — check everything you take with our drug–supplement interaction checker.

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.