Disopyramide and Sultopride: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Disopyramide
Sultopride
No brand names on record
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
An increased risk of cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest)
Interaction Deep Dive
The concurrent administration of a Class IA antiarrhythmic and an antipsychotic is not recommended, since Class IA antiarrhythmic agents may also prolong the QT interval and increase the risk of arrhythmias23.
Why it happens (mechanism)
Additive cardiac effects
Literature reports
4 reports — tap to read
a) In an open-label QTc study of patients with schizophrenia or schizoaffective disorder (n=160), iloperidone 12 mg twice a day was associated with QTc prolongation of 9 msec 2.
b) QRS widening, QTc interval prolongation, and torsades de pointes may occur with disopyramide therapy 4.
c) The effects of combined therapy with quiNIDine (Class IA antiarrhythmic agent) and haloperidol (antipsychotic agent) were studied by giving 12 healthy volunteers haloperidol 5 mg alone and with 250 mg of quiNIDine bisulfate. The study demonstrated significant increases in the plasma concentrations of haloperidol when given concurrently with quiNIDine versus haloperidol treatment alone. The mean area under the concentration curve (AUC) was increased from 54.3 ng/hr/mL on haloperidol alone to 103.2 ng/hr/mL on combined therapy. The Cmax also showed an increase from 1.9 ng/mL on haloperidol to 3.8 ng/mL on combined therapy. Half-life (T1/2) and Tmax were not significantly changed, thereby suggesting to the authors that a tissue binding mechanism is more likely responsible for the plasma level changes than an elimination alteration 5.
d) Several antipsychotic agents have demonstrated QT prolongation including haloperidol, iloperidone, paliperidone, risperiDONE, sertindole, sultopride, and zotepine 2671891011.
Common questions
Can I take Disopyramide and Sultopride together?
An increased risk of cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest) Always confirm with your pharmacist or prescriber before making any change.
How serious is the Disopyramide and Sultopride 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 "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Disopyramide or Sultopride 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 (11)
- Owens R: Risk assessment for antimicrobial agent-induced QTc prolongation and torsades de pointes. Pharmacother 2001; 21(3):310-319.
- Product Information: FANAPT(R) oral tablets, iloperidone oral tablets. Vanda Pharmaceuticals Inc (per FDA), Washington, DC, 2024. DailyMed
- Product Information: Quinaglute(R), quinidine gluconate. Berlex Laboratories, Wayne, NJ, 1999. DailyMed
- Product Information: Norpace(R), disopyramide. G.D. Searle & Co. Chicago, IL, 1997. DailyMed
- Young D, Midha KK, Fossler MJ, et al: Effect of quinidine on the interconversion kinetics between haloperidol and reduced haloperidol in humans: implications for the involvement of cytochrome P450IID6. Eur J Clin Pharmacol 1993; 44:433-438. PubMed
- O'Brien JM, Rockwood RP, & Suh KI: Haloperidol-induced torsade de pointes. Ann Pharmacother 1999; 33(10):1046-1050. DOI
- Product Information: INVEGA(TM) extended-release oral tablets, paliperidone extended-release oral tablets. Alza Corporation, Mountain View, CA, 2006. DailyMed
- 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
- 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
- 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.
- Sweetman S (Ed): Martindale: The Complete Drug Reference. London: Pharmaceutical Press. Electronic version, MICROMEDEX, Greenwood Village, Colorado, Edition expires 06/2003.
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