Drug & supplement interaction

Grapefruit Diet + Thioridazine

Thioridazine brand name: Mellaril.

No Known Interaction
Medically reviewed by · Updated June 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Grapefruit Diet and Thioridazine in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first.

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Interaction report

Grapefruit Diet and Thioridazine

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Thioridazine and Grapefruit Diet in our sources. This does not guarantee that the combination is completely free of risk — research on Grapefruit Diet alongside specific medications may be limited.

Worth understanding: our licensed dataset holds no drug-interaction record for Grapefruit Diet at all — not against Thioridazine, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

Grapefruit Diet is an eating pattern rather than something you take. Ask your pharmacist or doctor before changing how you eat while on a prescribed medicine: some medicines are dosed around meals, and a change in diet can change how they work. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Grapefruit Diet safety at a glance

Grapefruit Diet overall Use caution Grapefruit is a healthy food, but very low-calorie versions of this diet can be hard to sustain and grapefruit affects many medications.
Pregnancy Use caution Eating grapefruit as food is generally fine, but very low-calorie diets should be avoided during pregnancy.
Breastfeeding Use caution Grapefruit as food is usually fine, but restrictive dieting while breastfeeding is not recommended.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Thioridazine and Grapefruit Diet? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Thioridazine’s Own FDA Label Lists

This is not an interaction — none of it involves Grapefruit Diet. These are the most notable effects listed in the ADVERSE REACTIONS section of Thioridazine’s own FDA label, for the medication by itself. Knowing the drug’s own list makes it easier to work out the likely cause if something new turns up while you follow Grapefruit Diet and take the medicine. 10 of them are worth acting on rather than waiting out — marked below.

  • A bowel blockage Worth acting on
  • Yellowing of the skin or eyes Worth acting on
  • Wheezing Worth acting on
  • An irregular heartbeat Worth acting on
  • Confusion Worth acting on
  • Low mood Worth acting on
  • A low platelet count Worth acting on
  • Anemia Worth acting on
  • A low white blood cell count Worth acting on
  • Liver problems Worth acting on

Showing the 10 most notable of 33 label-listed effects — ranked by how unusual each one is across medicines generally, with serious effects weighted up.

From the ADVERSE REACTIONS section of the FDA label for Thioridazine. Read the label on DailyMed › Grapefruit Diet’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Grapefruit Diet side to compare — that is a limit of the record, not a statement that Grapefruit Diet has no side effects.

From our Q&A

Questions About Grapefruit Diet or Thioridazine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Grapefruit Diet or Thioridazine, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Thioridazine

This page covers Grapefruit Diet only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Thioridazine page lists 168 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Cesium (major) and Ephedra (major).

By severity: 11 major · 125 moderate · 32 minor.

From our pharmacist’s overview on the Thioridazine page

“Thioridazine (Mellaril) is an older antipsychotic already known for disturbing the heart's rhythm, and the supplements that worry me most here do the same thing, stretching the QT interval further. Grapefruit in large amounts sits in that group, alongside ephedra and several other major-rated entries.”

Reviewed by 2 · Jul 18, 2026

Open the Thioridazine interaction page

How much people look this up

Where Grapefruit Diet and Thioridazine Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Grapefruit Diet
Steady interest

#1,143 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Thioridazine
Steady interest

#2,091 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions. Grapefruit Diet is not yet covered by that licensed database, so its write-up cites publicly available medical sources directly (see the references below).
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Grapefruit Diet reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Grapefruit Diet and Thioridazine records this page draws on were last updated June 22, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Eating pattern

About Grapefruit Diet

What is Grapefruit Diet?

  • Weight loss
  • Appetite control
  • Short-term dieting
  • Blood sugar support
  • General 'detox' plans

The 'Grapefruit Diet' is a fad eating plan that pairs grapefruit or grapefruit juice with low-calorie meals, claiming the fruit burns fat. Any weight loss is most likely from cutting calories rather than a special fat-burning property of grapefruit. Grapefruit interacts with many medications, so talk to your pharmacist or doctor before starting.

Fruit and fruit juice (Citrus paradisi) · Fresh grapefruit, grapefruit juice, and as part of structured low-calorie meal plans; also grapefruit extract capsules sometimes marketed for weight loss

An interaction check asks whether these two react with each other — it does not ask whether Grapefruit Diet is a good idea for someone in your situation. Here is what our Grapefruit Diet record says about it on its own.

Grapefruit Diet: dosing

There is no standardized or medically established dose for the Grapefruit Diet. Plans typically suggest eating half a grapefruit or drinking a small glass of grapefruit juice with meals, but these amounts vary by version and are not based on solid research.If you choose to add grapefruit to your diet, a reasonable, food-based approach is far safer than a strict, very low-calorie plan.

From our Grapefruit Diet monograph — the full record covers uses, side effects and every documented interaction.

Read the full Grapefruit Diet monograph & all interactions
Medication

About Thioridazine

What Is Thioridazine Used For?

Brand name: Mellaril

Thioridazine Hydrochloride tablets are used for the management of schizophrenia — but only in patients who have already tried at least two other antipsychotic medications without adequate results, either because those drugs didn't work well enough or caused intolerable side effects.

Because thioridazine carries serious heart-rhythm risks, it is considered a last-resort option for schizophrenia, not a first-line treatment. It is not approved for dementia-related psychosis or any other psychiatric condition.

See full Thioridazine drug information
Keep checking

Other Drugs & Grapefruit Diet

Browse every other medication we’ve checked against Grapefruit Diet — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

We also checked Grapefruit Diet against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Grapefruit Diet list.

See the full Grapefruit Diet interactions page
See every supplement checked against Thioridazine, ranked by severity
Evidence & sources

Grapefruit Diet References

The 2 sources that drive our Grapefruit Diet monograph — publicly available pages from reputable medical and government organizations. Every link was verified to work before publishing. Grapefruit Diet is not covered by the licensed Natural Medicines interaction database, so its page cites these public sources directly.

  1. Grapefruit — MedlinePlus Source
  2. Choosing a Safe and Successful Weight-Loss Program — NIH NIDDK Source

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Following Grapefruit Diet While Taking Thioridazine: Common Questions

Is it safe to follow Grapefruit Diet while taking Thioridazine?
We do not list a known interaction between Grapefruit Diet and Thioridazine. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Does Thioridazine interact with any supplements?
Yes. Thioridazine has documented interactions with 168 supplements in our database — Grapefruit Diet is not one of them. The Thioridazine interaction page linked on this page lists every one, ranked by severity.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Where next

Keep Exploring

Grapefruit Diet monograph Uses, safety profile, and every drug interaction in one place Thioridazine drug information The full plain-English guide to this medication Thioridazine supplement interactions Every supplement checked against Thioridazine, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 2 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Thioridazine and Grapefruit Diet?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.