Drug & supplement interaction

Grapefruit Diet + Perphenazine

Perphenazine brand name: Trilafon.

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 Perphenazine 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 Perphenazine

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 Perphenazine 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 Perphenazine, 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 Perphenazine and Grapefruit Diet? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Perphenazine’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 Perphenazine’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
  • Muscle weakness Worth acting on
  • Trouble swallowing Worth acting on
  • Trouble passing urine Worth acting on
  • Unsteadiness Worth acting on
  • Low blood sugar Worth acting on
  • A slow heartbeat Worth acting on
  • Yellowing of the skin or eyes Worth acting on
  • High blood sugar Worth acting on
  • Wheezing Worth acting on

Showing the 10 most notable of 50 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 Perphenazine. 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.

Everything else you take

See Every Supplement That Interacts With Perphenazine

This page covers Grapefruit Diet only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Perphenazine page lists 147 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Henbane (major), Indian Snakeroot (major), Rauvolfia Vomitoria (major) and Scopolia (major).

By severity: 5 major · 108 moderate · 34 minor.

From our pharmacist’s overview on the Perphenazine page

“Perphenazine (Trilafon) treats schizophrenia and severe nausea, and this list deserves real care. Five of the 147 ingredients on file rate major, and those five are the ones to understand first.”

Reviewed by 2 · Jul 18, 2026

Open the Perphenazine interaction page

How much people look this up

Where Grapefruit Diet and Perphenazine 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

#1,189 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Perphenazine
Steady interest

#1,620 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 Perphenazine 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 Perphenazine

What Is Perphenazine Used For?

Brand name: Trilafon

Perphenazine tablets are approved to treat schizophrenia in adults. They are also used to control severe nausea and vomiting in adults when other measures are not enough.

Perphenazine has not been shown effective for managing behavioral problems in patients with intellectual disabilities, and it is not approved for dementia-related psychosis in elderly patients.

See full Perphenazine 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 Perphenazine, 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 Perphenazine: Common Questions

Is it safe to follow Grapefruit Diet while taking Perphenazine?
We do not list a known interaction between Grapefruit Diet and Perphenazine. 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 Perphenazine interact with any supplements?
Yes. Perphenazine has documented interactions with 147 supplements in our database — Grapefruit Diet is not one of them. The Perphenazine 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 Perphenazine drug information The full plain-English guide to this medication Perphenazine supplement interactions Every supplement checked against Perphenazine, 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 Perphenazine 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.