Drug & supplement interaction

Grapefruit Diet + Valrubicin

Valrubicin brand name: Valstar.

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 Valrubicin 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 Valrubicin

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

What Valrubicin’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 Valrubicin’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. 6 of them are worth acting on rather than waiting out — marked below.

  • Pain or burning when passing urine Worth acting on
  • Trouble passing urine Worth acting on
  • High blood sugar Worth acting on
  • Chest pain Worth acting on
  • Anemia Worth acting on
  • A higher chance of infection Worth acting on
  • Loss of bladder control
  • Passing urine more often
  • Bloating or gas
  • Back pain

Showing the 10 most notable of 22 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 Valrubicin. 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 Valrubicin

This page covers Grapefruit Diet only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Valrubicin page lists 24 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Acerola (moderate), Alpha-lipoic Acid (moderate), Coffee Charcoal (moderate) and European Mandrake (moderate).

By severity: 1 major · 14 moderate · 9 minor.

From our pharmacist’s overview on the Valrubicin page

“Activated charcoal is the supplement I would flag hardest for anyone receiving valrubicin (Valstar), a chemotherapy instilled directly into the bladder for cancer. It carries the only major rating among the 24 ingredients on this page, since charcoal can bind and clear many drugs from the body even when they are not swallowed.”

Reviewed by 2 · Jul 18, 2026

Open the Valrubicin interaction page

How much people look this up

Where Grapefruit Diet and Valrubicin 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 Valrubicin
Steady interest

#2,736 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 Valrubicin 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 Valrubicin Intravesical

What Is Valrubicin Intravesical Used For?

Brand name: Valstar

Valrubicin Intravesical Solution is used to treat BCG-refractory carcinoma in situ (CIS) of the urinary bladder — meaning bladder cancer that has not responded to BCG immunotherapy. It is given directly into the bladder (intravesically) rather than taken by mouth or injected into the bloodstream.

This treatment is specifically for patients whose cancer has not responded to BCG and for whom having the bladder surgically removed (cystectomy) right away would carry unacceptable health risks.

Most-Reported Side Effects for Valrubicin

From FAERS, the FDA’s public side-effect reporting system (177 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Underdose 26 reports
Bladder instillation procedure 24 reports
Urge incontinence 20 reports
Bladder spasm 13 reports
Urinary incontinence 11 reports
See full Valrubicin Intravesical 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 Valrubicin, 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 Valrubicin: Common Questions

Is it safe to follow Grapefruit Diet while taking Valrubicin?
We do not list a known interaction between Grapefruit Diet and Valrubicin. 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 Valrubicin interact with any supplements?
Yes. Valrubicin has documented interactions with 24 supplements in our database — Grapefruit Diet is not one of them. The Valrubicin 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 Valrubicin Intravesical drug information The full plain-English guide to this medication Valrubicin supplement interactions Every supplement checked against Valrubicin, 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 Valrubicin 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.