Drug & supplement interaction

Vitamin D + Obinutuzumab

Obinutuzumab brand name: Gazyva.

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

We found no known interaction between Vitamin D and Obinutuzumab 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. Additionally, although there is no interaction, the label for Obinutuzumab states a food rule worth keeping to, and the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Vitamin D and Obinutuzumab

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 Obinutuzumab and Vitamin D in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. 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.

Vitamin D safety at a glance

Vitamin D overall Generally safe Vitamin D is generally safe at recommended doses, but very high doses over time can cause toxicity.
Pregnancy Likely Safe When used orally and appropriately. Vitamin D is safe when used in doses below the tolerable upper intake level (UL) of 4000 IU (100 mcg) daily. Read the full pregnancy detail
Breastfeeding Likely Safe When used orally and appropriately. Vitamin D is safe when used in doses below the tolerable upper intake level (UL) of 4000 IU (100 mcg) daily. Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Obinutuzumab and Vitamin D? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
Keep it in perspective

Vitamin D Does Interact With Other Medications

Vitamin D has 80 moderate, 635 minor known drug interactions in our database — Obinutuzumab isn’t one of them. If you take anything else, check it against the full list below.

Moderate 80 Minor 635 No known interaction 2,115 (incl. Obinutuzumab)
Taking anything else?

Check Another of Your Medications Against Vitamin D

Covers the 2,830 medications we’ve checked against Vitamin D. Pick one to open its full report.

What to actually watch for

No Interaction Found — But Data Suggests Vitamin D and Obinutuzumab May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. 2 of them are worth acting on rather than waiting out — marked below.

  • Kidney problems Worth acting on Additional detail

    Vitamin D

    “Vitamin D intoxication can occur when vitamin D supplements are taken orally in excessive doses. Symptoms of vitamin D toxicity include azotemia. Vitamin D may also cause hypercalcemia, with advanced symptoms including kidney stones or kidney insufficiency due to precipitation of calcium phosphate in the tubules.”

    Vitamin D · Natural Medicines adverse-effect record, reported in hypercalcemia.

    5 sources cited
    1. 10142. Koutkia P, Chen TC, Holick MF. Vitamin D intoxication associated with an over-the-counter supplement. N Engl J Med 2001;345:66-7. PubMed
    2. 93002. Weiner M, Epstein FH. Signs and symptoms of electrolyte disorders. Yale J Biol Med. 1970;43(2):76-109.
    3. 93943. Lappe J, Watson P, Travers-Gustafson D, Recker R, Garland C, Gorham E, Baggerly K, McDonnell SL. Effect of Vitamin D and Calcium Supplementation on Cancer Incidence in Older Women: A Randomized Clinical Trial. JAMA. 2017 Mar 28;317(12):1234-1243. PubMed
    4. 110831. Doyle D, Browne U, Brickley A, Murphy D. Vitamin D-induced hypercalcaemia and acute kidney injury in sarcoidosis. BMJ Case Rep 2023;16(1):e250580. PubMed
    5. 110833. Williamson A, Martineau AR, Sheikh A, Jolliffe D, Griffiths CJ. Vitamin D for the management of asthma. Cochrane Database Syst Rev 2023;2(2):CD011511. PubMed

    Obinutuzumab

    Listed in the ADVERSE REACTIONS section of the FDA label for Obinutuzumab. Read the label on DailyMed ›

  • Anemia Worth acting on Additional detail

    Vitamin D

    “Orally or intramuscularly, vitamin D is well tolerated.

    Serious Adverse Effects (Rare):

    Orally or intramuscularly: Excessive doses can lead to vitamin D toxicity with symptoms of hypercalcemia, and also sometimes azotemia and anemia.”

    Vitamin D · Natural Medicines adverse-effect record, reported in anemia.

    Obinutuzumab

    Listed in the ADVERSE REACTIONS section of the FDA label for Obinutuzumab. Read the label on DailyMed ›

Reported for Vitamin D but not commonly for Obinutuzumab: a change in sex drive, kidney stones, pancreatitis and raised blood pressure.

Effects for Obinutuzumab come from the ADVERSE REACTIONS section of its FDA label; effects for Vitamin D come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Vitamin D in Pregnancy & Breastfeeding

Pregnancy Likely Safe

When used orally and appropriately. Vitamin D is safe when used in doses below the tolerable upper intake level (UL) of 4000 IU (100 mcg) daily.

Pregnancy Possibly Unsafe

When used orally in excessive amounts. Tell patients not to use doses above the tolerable upper intake level (UL) of 4000 IU (100 mcg) daily. Hypercalcemia during pregnancy due to excessive vitamin D intake can lead to several fetal adverse effects, including suppression of parathyroid hormone, hypocalcemia, tetany, seizures, aortic valve stenosis, retinopathy, and mental and/or physical developmental delay.

Lactation Likely Safe

When used orally and appropriately. Vitamin D is safe when used in doses below the tolerable upper intake level (UL) of 4000 IU (100 mcg) daily.

Lactation Possibly Unsafe

When used orally in excessive amounts. Tell patients not to use doses above the tolerable upper intake level (UL) of 4000 IU (100 mcg) daily.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

How to take them

Some Obinutuzumab Products Have a Food Rule — Vitamin D Should Not Break It

At least one FDA label for a product containing Obinutuzumab says to take it on an empty stomach. Most supplements — Vitamin D included — are taken with a meal, so the easy mistake is swallowing both together at breakfast. Where that rule applies, keep Obinutuzumab on its own and move Vitamin D to a meal later in the day.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Obinutuzumab products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

650–1,000 mg acetaminophen At least 30 minutes before GAZYVA infusion.

From the Dosage and Administration section of the FDA label we read for Obinutuzumab — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

From our Q&A

Questions About Vitamin D or Obinutuzumab

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Vitamin D or Obinutuzumab, 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.

One more smart check

Taking Vitamin D as Part of a Dietary Supplement Product? Check It for Interactions

We hold 26,930 real supplement products containing Vitamin D, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Vitamin D. Even though Vitamin D itself has no known interaction with Obinutuzumab, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Vitamin D and Obinutuzumab 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 Vitamin D
Top 10

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

29 days ago today
Medication Obinutuzumab
Steady interest

#2,267 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.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Vitamin D reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Vitamin D and Obinutuzumab records this page draws on were last updated July 11, 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 .
Supplement

About Vitamin D

What is Vitamin D?

Vitamin D
  • Bone health and osteoporosis
  • Correcting vitamin D deficiency
  • Immune system support
  • Muscle strength in older adults
  • General supplementation when sun exposure is low

Vitamin D is a fat-soluble vitamin that helps your body absorb calcium and is important for healthy bones, muscles, and immune function. Many people, especially those with low sun exposure, benefit from supplementation, but more is not always better and very high doses can be harmful. Ask your pharmacist or doctor whether a blood test and supplement make sense for you.

Not applicable (a vitamin, not a plant part) · Tablets, capsules, softgels, liquid drops, chewables, and injections

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

Vitamin D: dosing

The right dose of vitamin D depends on your age, blood level, health conditions, and how much sun and dietary vitamin D you get. There is no single dose that fits everyone.Supplements come in different strengths, and doses are measured in international units (IU) or micrograms (mcg). Some people only need a small daily amount, while those who are deficient may need a higher, supervised dose for a period of time.The best approach is to follow the directions on the product label or the advice of your pharmacist or doctor. A simple blood test can show whether you are low and help guide the right dose.

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

Read the full Vitamin D monograph & all interactions
Medication

About Obinutuzumab Injection

What Is Obinutuzumab Injection Used For?

Brand name: Gazyva

Gazyva is used to treat three conditions. For chronic lymphocytic leukemia (CLL), it is given in combination with chlorambucil in patients who have not been treated before. For follicular lymphoma (FL), it is used either with bendamustine (for patients whose disease came back or stopped responding to a rituximab-based regimen) or with chemotherapy (for previously untreated advanced disease) — in both cases followed by Gazyva alone as maintenance therapy.

Gazyva is also approved for active lupus nephritis — a type of kidney inflammation caused by lupus — in adults who are already receiving standard therapy for the condition.

See full Obinutuzumab Injection drug information
Keep checking

Other Drugs & Vitamin D

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

0Major
80Moderate
635Minor
2,114No known interaction
80 Moderate 635 Minor 2,114 No interaction
Moderate

80 interactions

Showing 60 of 80 moderate interactions — see all 80 on the Vitamin D page.

Minor

635 interactions

Showing 60 of 635 minor interactions — see all 635 on the Vitamin D page.

No interaction 2,114 drugs checked — show the list

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

Showing the 60 most looked-up of 2,114 medications checked with no known interaction — see the full Vitamin D list.

See the full Vitamin D interactions page
See every supplement checked against Obinutuzumab, ranked by severity
Evidence & sources

Vitamin D References

The 26 references that drive our Vitamin D monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
  2. Tatro DS, ed. Drug Interactions Facts. Facts and Comparisons Inc., St. Louis, MO. 1999.
  3. Koutkia P, Chen TC, Holick MF. Vitamin D intoxication associated with an over-the-counter supplement. N Engl J Med 2001;345:66-7. PubMed
  4. Bar-Or D, Yoel G. Calcium and calciferol antagonize effect of verapamil in atrial fibrillation. Br Med J 1981;282:1585-6.
  5. Demontis R, Leflon A, Fournier A, et al. 1 alpha(OH) vitamin D3 increases plasma aluminum in hemodialyzed patients taking AI(OH)3. Clin Nephrol 1986;26:146-9.
  6. Crowe M, Wollner L, Griffiths RA. Hypercalcemia following vitamin D and thiazide therapy in the elderly. Practitioner 1984;228:312-3.
  7. Parfitt AM. Thiazide-induced hypercalcemia in vitamin D-treated hypoparathyroidism. Ann Intern Med 1972;77:557-63. PubMed
  8. Thiazide diuretics and the risk of osteoporosis. Pharmacist's Letter/Prescriber's Letter 2003;19(11):191105.
  9. Moon J. The role of vitamin D in toxic metal absorption. J Am Coll Nutr 1994;13:559-64.
  10. Demontis R, Reissi D, Noel C, et al. Indirect clinical evidence that 1alphaOH vitamin D<SUB>3</SUB> increases the intestinal absorption of aluminum. Clin Nephrol 1989;31:123-7.
  11. Adler AJ, Berlyne GM. Duodenal aluminum absorption in the rat: effect of vitamin D. Am J Physiol 1985;249:G209-13. PubMed
  12. Schwartz JB. Effects of vitamin D supplementation in atorvastatin-treated patients: A new drug interaction with an unexpected consequence. Clin Pharmacol Ther 2009;85:198-203. PubMed
  13. Dietary reference intakes for calcium and vitamin D. Institute of Medicine, November 30, 2010. Available at: http://www.iom.edu/~/media/Files/Report%20Files/2010/Dietary-Reference-Intakes-for-Calcium-and-Vitamin-D/Vitamin%20D%20and%20Calcium%202010%20Repo
  14. Cox KA, Dunn MA. Aluminum toxicity alters the regulation of calbindin-D28k protein and mRNA expression in chick intestine. J Nutr 2001;131:2007-13. PubMed
  15. Escribano, J., Balaguer, A., Pagone, F., Feliu, A., and Roque, I. Figuls. Pharmacological interventions for preventing complications in idiopathic hypercalciuria. Cochrane.Database.Syst.Rev. 2009;(1):CD004754. PubMed

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

Taking Vitamin D and Obinutuzumab Together: Common Questions

Is it safe to take Vitamin D with Obinutuzumab?
We do not list a known interaction between Vitamin D and Obinutuzumab. 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.
Do Vitamin D and Obinutuzumab have any of the same side effects?
Yes — our sources link each of them separately to 2 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Should I take Vitamin D and Obinutuzumab at the same time of day?
At least one FDA label for a product containing Obinutuzumab says to take it on an empty stomach, and supplements are usually taken with a meal — so taking them together at breakfast is the easy mistake. Where that applies, keep Obinutuzumab on its own and move Vitamin D to a meal later in the day. Food instructions belong to the product rather than the ingredient, so check the directions on your own box. This is about absorption, not an interaction.
Does Vitamin D interact with any other medications?
Yes. Vitamin D has 715 documented drug interactions in our database — Obinutuzumab is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.

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

Where next

Keep Exploring

Vitamin D monograph Uses, safety profile, and every drug interaction in one place Obinutuzumab Injection drug information The full plain-English guide to this medication Obinutuzumab supplement interactions Every supplement checked against Obinutuzumab, 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 26 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Obinutuzumab and Vitamin D?

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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.