Phosphate Salts + Erdafitinib
Erdafitinib brand name: Balversa.
Phosphate Salts has a major interaction with Erdafitinib. Taking erdafitinib with phosphate salts increases the risk of hyperphosphatemia.
Read the full interaction reportPhosphate Salts and Erdafitinib
Here is the interaction we found between these two, with the evidence behind it.
ERDAFITINIB (Balversa)
Erdafitinib increases phosphate levels. It is recommended that patients taking erdafitinib restrict phosphate intake to no more than 600-800 mg daily.
Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports..
Here's the key thing about erdafitinib (Balversa): this medicine raises the phosphate level in your blood all on its own. That's actually how the cancer doctors track whether the dose is working, but it also means too much phosphate can build up, a condition called hyperphosphatemia. Adding a phosphate salt supplement on top of that pours fuel on the fire, pushing your levels even higher.
Why does that matter? High phosphate can lead to problems like muscle cramps, itching, and over time it can pull calcium out of your bones or cause mineral buildup in your tissues. Because of this, people on erdafitinib are usually told to keep phosphate intake to roughly 600 to 800 mg a day. Don't start or stop any supplement on your own. Please loop in your oncologist or pharmacist first, since they're already monitoring your phosphate.
- Prescribing information: BALVERSA (erdafitinib) tablets. U.S. Food and Drug Administration. https://www.accessdata.fda.gov/drugsatfda_docs/label/2019/212018s000lbl.pdf. [Accessed: February 26, 2021.]
What These Ratings Mean
Every interaction above is graded three ways — here’s the key to each label.
Clinically significant. Avoid the combination, or use only under close professional supervision.
Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.
Generally not serious. Be aware of it and mention it to your pharmacist.
- LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
- ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
- PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
- UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
- AHigh-quality meta-analysis (quantitative systematic review).
- BCase-control study.
- CConsensus.
- DAnecdotal evidence.
These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.
Phosphate Salts Also Interacts With Other Medications
Phosphate Salts has 1 major, 10 moderate known drug interactions in our database — the Erdafitinib one above is one of them. If you take anything else, check it against the full list below.
Check Another of Your Medications Against Phosphate Salts
We haven’t checked that one against Phosphate Salts yet — ask our pharmacists directly.
Covers the 2,830 medications we’ve checked against Phosphate Salts. Pick one to open its full report.
See Every Supplement That Interacts With Erdafitinib
This page covers Phosphate Salts only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Erdafitinib page lists 169 supplements it has a documented interaction with, worst first, each one explained.
The most serious there right now: Activated Charcoal (major), Grapefruit (major), St. John's Wort (major), Acacia Rigidula (moderate) and Adrafinil (moderate).
By severity: 4 major · 127 moderate · 38 minor.
From our pharmacist’s overview on the Erdafitinib page
“Erdafitinib (Balversa) treats bladder cancers driven by FGFR gene changes, and its benefit depends on holding a steady drug level, so this is a list to be genuinely careful with. Four entries are rated major.”
Reviewed by 2 · Jul 18, 2026
Taking Phosphate Salts as Part of a Dietary Supplement Product? Check It for Interactions
We hold 6 real supplement products containing Phosphate Salts, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Phosphate Salts. Your product may carry other ingredients that interact with Erdafitinib too, on top of Phosphate Salts — and those would not show on this page. Find your product and we’ll check every ingredient on its label:
Where Phosphate Salts and Erdafitinib 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.
#1,150 of 1,452 supplements looked up here in the last 7 days
#1,903 of 2,830 medications looked up here in the last 7 days
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.
About Phosphate Salts
What is Phosphate Salts?
- Low blood phosphate levels (hypophosphatemia)
- Bowel preparation/laxative use
- Athletic performance ('phosphate loading')
- Preventing certain kidney stones
- Calcium supplementation balance
Phosphate salts are mineral compounds used mainly to correct low phosphate levels, as laxatives, and sometimes by athletes. Most people who eat a normal diet already get plenty of phosphate and do not need a supplement. Because too much phosphate can be dangerous—especially for people with kidney disease—use these products only under the guidance of a doctor or pharmacist.
About Erdafitinib
What Is Erdafitinib Used For?
Brand name: Balversa
Balversa (erdafitinib) is used to treat adults with locally advanced or metastatic urothelial carcinoma (UC) — cancer of the bladder or urinary tract — that has spread and has not responded to, or has gotten worse after, at least one prior round of systemic treatment. Patients must have a specific type of FGFR3 genetic alteration in their tumor, confirmed by an FDA-approved test before starting.
Balversa is not recommended for patients who are eligible for — but have not yet received — a PD-1 or PD-L1 inhibitor (a type of immunotherapy). Those therapies should be tried first when appropriate.
Other Drugs & Phosphate Salts
Browse every other medication we’ve checked against Phosphate Salts — both the ones with a known interaction and the ones without. Select any drug for the full detail.
No drugs match “”.
1 interaction
10 interactions
No interaction 2,818 drugs checked — show the list
We also checked Phosphate Salts against these medications and found no known interaction in our sources. Open any page to confirm.
- Apixaban ›
- Levothyroxine ›
- Amlodipine ›
- Methylphenidate ›
- Warfarin ›
- Sertraline ›
- Testosterone ›
- Losartan Potassium ›
- Metoprolol ›
- Aspirin ›
- Ivermectin ›
- Rivaroxaban ›
- Rosuvastatin ›
- Escitalopram ›
- Tadalafil ›
- Acetaminophen ›
- Clopidogrel ›
- Atorvastatin ›
- Valacyclovir ›
- Docusate ›
- Hydroxyurea ›
- Abemaciclib ›
- Ibuprofen ›
- Methamphetamine ›
- Semaglutide ›
- Sumatriptan ›
- Tirzepatide ›
- Warfarin Sodium ›
- Prednisone ›
- Propranolol ›
- Lisdexamfetamine ›
- Bupropion ›
- Metformin ›
- Amoxicillin ›
- Acyclovir ›
- Lisinopril ›
- Bendamustine ›
- Amitriptyline ›
- Doxycycline ›
- Lamotrigine ›
- Fluoxetine ›
- Methotrexate ›
- Pregabalin ›
- Gabapentin ›
- Amphetamine ›
- Acetaminophen, Codeine ›
- Isotretinoin ›
- Azithromycin ›
- Dextroamphetamine ›
- Clonazepam ›
- Omeprazole ›
- Quetiapine ›
- Methylene Blue ›
- Amlodipine Besylate ›
- Duloxetine ›
- Letrozole ›
- Buspirone ›
- Citalopram ›
- Ciprofloxacin ›
- Naproxen ›
Showing the 60 most looked-up of 2,818 medications checked with no known interaction — see the full Phosphate Salts list.
Sources & How We Checked
Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference for vitamins, herbs and supplements — the basis for our interaction data.
- MedlinePlus, U.S. National Library of Medicine — NIH consumer drug information, used for the medication overviews.
- NIH Dietary Supplement Label Database (DSLD) — Official supplement product labels.
Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.
Parts of this content are provided by the Therapeutic Research Center, LLC.
DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.
© 2021 Therapeutic Research Center, LLC
Taking Phosphate Salts and Erdafitinib Together: Common Questions
Can you take Phosphate Salts with Erdafitinib?
How serious is the Phosphate Salts and Erdafitinib interaction?
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