The short answer
A direct magnesium-citrate interaction causing QT prolongation with ziprasidone is not established. The dose, laxative use, kidney function and electrolyte status need separate review.
What this answer covers
Magnesium citrate, distinct from magnesium hydroxide antacid and combination colonoscopy preparations.
- Supplement or preparation
- Magnesium citrate
- Medication ingredient
- ziprasidone
Low magnesium is a different issue
Ziprasidone warns about low magnesium and potassium as rhythm-risk factors. That does not establish that magnesium citrate itself is a QT-prolonging drug.
A bowel-preparation study offers limited reassurance
Selected colonoscopy patients using sodium picosulfate plus magnesium citrate had modest transient magnesium increases without an associated clinically significant conduction effect. They were not an identified ziprasidone group.
An antacid result involves another salt
A magnesium-hydroxide/aluminium-hydroxide antacid did not change oral ziprasidone exposure significantly. This cannot be relabeled as evidence for magnesium citrate.
Review laxative and electrolyte problems
Tell the clinician about the product, dose, kidney function and persistent diarrhea. Let the treating team decide whether testing or a different bowel regimen is needed; no universal supplement gap is established.
Evidence and practical considerations
Side effects & toxicity
Exact magnesium-citrate QT/arrhythmia claim remains insufficiently established.
- Exact scope
- Magnesium citrate, distinct from magnesium hydroxide antacid and combination colonoscopy preparations. with Exact ziprasidone hydrochloride oral capsules or mesylate intramuscular injection, distinguished by route. Exact RxNorm IN115698; hydrochloride oral capsule and mesylate intramuscular formulation distinct. Oral food and antacid findings do not apply to injection absorption.
- Medication form and route
- oral; intramuscular
- Timing or duration
- Source-specific single-dose, repeated-dose and observational exposures distinguished.
What remains uncertain
- No exact co-use study; low electrolytes, excessive magnesium and bowel preparation are different mechanisms and exposures.
Factors that may matter: preparation and plant part; clinical indication; dose; other medicines; baseline alertness.
Read the supporting source summaries
Source 1: current product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: People prescribed ziprasidone.
Somnolence, QT and electrolyte precautions; low potassium or magnesium requires assessment/correction before proceeding; oral capsules taken with food.
How this applies: Exact RxNorm IN115698; hydrochloride oral capsule and mesylate intramuscular formulation distinct. Oral food and antacid findings do not apply to injection absorption.
No supplement-specific event rate, universal timing rule or untested route/preparation equivalence.
Source 2: original human study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: 598 selected colonoscopy patients from two trials.
Transient modest magnesium rises; no clinically significant cardiac-conduction effect attributed to elevated magnesium.
How this applies: Only the named drug, preparation, route and measured endpoints apply.
Combination bowel preparation, not isolated supplement or ziprasidone co-use. Important renal, electrolyte and cardiac exclusions limit high-risk generalization.
Source 3: original human study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: Eleven healthy adults in crossover study.
No significant change in ziprasidone exposure or peak concentration with the antacid.
How this applies: Only the named drug, preparation, route and measured endpoints apply.
Magnesium hydroxide/aluminium hydroxide combination, not magnesium citrate. No injection route, arrhythmia endpoint or long-term nutritional requirement.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Research summary published | |
| Article prepared | |
| Current exact available claims adjudicated using original captures and explicit identity and comparator limits. |
Article revision: 816adc3a8cf486b7
This guide brings together the evidence records used by our interaction checker. Each finding retains its own preparation limits, research date, and source summaries.
Full citations require verification. Reading this answer and the source summaries does not.
Taking other supplements or medications?
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Open the interaction checkerInformation, not medical advice. Do not change prescribed treatment based on this guide.