Pimozide and Relugolix: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 2, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Pimozide
No brand names on recordRelugolix
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.
Taking pimozide and relugolix together is not recommended. Both of these medicines can affect your heart's electrical rhythm in the same way. They can each stretch out a part of your heartbeat called the QT interval. When two drugs do this at the same time, the effect can add up and raise the risk of a dangerous irregular heartbeat.
The good news is this is very manageable. Your care team knows about this combination and can choose a safer option or watch your heart closely. Please do not stop or change either medicine on your own. Talk with your doctor or pharmacist so they can help you find the safest plan.
Contraindicated combination: additive QT prolongation. Both pimozide and relugolix are associated with QTc prolongation. Coadministration produces additive PD risk of QT interval prolongation and potentially serious ventricular arrhythmias, including torsades de pointes. Neither drug is the affected/perpetrator in a PK sense here; the concern is pharmacodynamic additivity.
- Direction: increased combined QT effect
- Evidence: probable; onset: unspecified
- Aggravating factors: hypokalemia, hypomagnesemia, other QT-prolonging agents
Management: Avoid concurrent use. If unavoidable, correct electrolytes, obtain baseline and follow-up ECGs, and consider an alternative agent. Dosing should be individualized by the care team.
What happens
An increased risk of QT interval prolongation
Interaction Deep Dive
Pimozide should not be given together with agents known to prolong the QT interval, because combining them can heighten the likelihood of QT interval prolongation and dangerous ventricular arrhythmias. This combination is likewise contraindicated in individuals receiving other medications that lengthen the echocardiographic QT interval, as well as in those with recognized hypokalemia or hypomagnesemia1.
Why it happens (mechanism)
Additive QT interval prolongation
How to manage this interaction
This combination is generally avoided. Because both drugs can affect heart rhythm, your care team will usually look for a safer alternative for one of them.
- Keep taking both medicines exactly as prescribed until your doctor or pharmacist advises a change.
- Your team may check an ECG and your blood potassium and magnesium levels, and may monitor you more closely.
- Tell your prescriber about all other medicines you take, since some also affect heart rhythm.
- Report symptoms like fainting, palpitations, dizziness, or a racing or irregular heartbeat right away.
Your care team can manage this by choosing the right medicines for you and monitoring as needed.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
4 reports — tap to read
a) In a controlled study, a single 2 mg dose of pimozide administered together with racemic citalopram 40 mg once daily over 11 days produced a mean rise in QTc values of roughly 10 msec relative to pimozide administered by itself. Racemic citalopram did not change the mean AUC or Cmax of pimozide. The basis for this pharmacodynamic interaction remains unknown 1.
b) Case-control studies showed a link between serious ventricular arrhythmias and sudden cardiac death, especially at domperidone doses exceeding 30 mg/day and when domperidone was used in patients over 60 years of age 2.
c) In experimental studies involving conditions other than Tourette's Disorder, sudden and unexpected deaths have been reported in patients receiving pimozide at approximately 1 mg per kg. A potential mechanism for these deaths is prolongation of the QT interval, which may predispose patients to ventricular arrhythmia. Obtain an electrocardiogram before starting pimozide therapy and at intervals afterward, particularly during the phase of dose adjustment 1.
d) Sultopride can cause prolongation of the QT interval and ventricular arrhythmias, including torsades de pointes, after therapeutic or toxic doses 345.
Common questions
Can I take Pimozide and Relugolix together?
Pimozide and relugolix both prolong the QT interval, so using them together is contraindicated because of the added risk of dangerous heart rhythms. Do not stop either drug on your own; ask your doctor or pharmacist to help find a safer plan. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Pimozide and Relugolix 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 is the Pimozide and Relugolix interaction managed?
This combination is generally avoided. Because both drugs can affect heart rhythm, your care team will usually look for a safer alternative for one of them. Keep taking both medicines exactly as prescribed until your doctor or pharmacist advises a change. Your team may check an ECG and your blood potassium and magnesium levels, and may monitor you more closely. Tell your prescriber about all other… Management is individual — always follow your own care team's guidance.
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 Pimozide or Relugolix 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 (5)
- Product Information: Pimozide oral tablet, pimozide oral tablet. Endo USA, Inc (per DailyMed), Malvern, PA, 2017. DailyMed
- Teva Canada Limited: Dear Healthcare Professional letter for domperidone maleate. Teva Canada Limited. Toronto, Canada. 2012.
- 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.
- Montaz L, Varache N, Harry P, et al: Torsades de pointes during sultopride poisoning. J Toxicol Clin Exp 1992; 12:481-496.
- Harry P: Acute poisoning by new psychotropic drugs. Rev Prat 1997; 47:731-735.
Keep reading about Pimozide
Keep reading about Relugolix
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