Drug Interaction Report

Ganciclovir and Probenecid: Interaction Details

A pharmacist-reviewed analysis of the Ganciclovir and Probenecid interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Probenecid

No brand names on record
+

Ganciclovir

Cytovene® Oral Zirgan
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
LinkedIn
Interaction severity
Moderate
Can be significant — usually manageable with monitoring.
How we grade severity & evidence

Severity levels

  • Contraindicated: These should generally not be used together.
  • Major: Potentially serious — often needs a change or close monitoring.
  • Moderate: Can be significant — usually manageable with monitoring.
  • Minor: Usually limited clinical impact.

Evidence grades

  • Established: Well documented — supported by controlled studies or strong clinical data.
  • Probable: Good supporting evidence, though not definitively proven.
  • Suspected: Some evidence suggests this interaction, but it is not well established.
  • Possible: Limited or conflicting evidence; the interaction may occur.
  • Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.

Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.

Of 17 documented Ganciclovir interactions, 3 are rated moderate — including this one.
Onset
delayed
Evidence
theoretical
Severity
Moderate

What happens

Increased risk for ganciclovir toxicity

Interaction Deep Dive

Concomitant use of ganciclovir and probenecid resulted in an increase in ganciclovir AUC and a decrease in ganciclovir renal clearance . This is consistent with an interaction involving competition for renal tubular secretion1. Because valganciclovir is a prodrug of ganciclovir, a similar interaction is expected when probenecid and valganciclovir are coadministered. If concomitant use of probenecid and ganciclovir or valganciclovir is required, the patient should be monitored for evidence of ganciclovir toxicity (ie, fever, nausea, vomiting, and diarrhea) 2.

Why it happens (mechanism)

Competition for renal tubular secretion

Literature reports

1 report — tap to read

a) When oral ganciclovir 1000 mg every 8 hours was administered concurrently with probenecid 500 mg every 6 hours (n=10), ganciclovir AUC increased 53 +/- 91% (range: -14% to 299%) and renal clearance of ganciclovir decreased 22 +/- 20% (range: -54% to -4%) 1.

Common questions

Can I take Ganciclovir and Probenecid together?

Increased risk for ganciclovir toxicity Always confirm with your pharmacist or prescriber before making any change.

How serious is the Ganciclovir and Probenecid interaction?

It is rated moderate. Can be significant — usually manageable with monitoring.

How quickly could this interaction happen?

The documented onset is "delayed". Effects tend to build up gradually over days to weeks.

How strong is the evidence for this interaction?

The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.

From our Q&A

Real reader questions about these medications, each personally answered by our pharmacist:

Questions for your pharmacist

  • Does my dose of Ganciclovir or Probenecid need adjusting while I take them together?
  • What symptoms should prompt me to call you or my prescriber right away?
  • Does the timing of my doses matter for this combination?
  • Is there anything you'd monitor while I'm on both?

References (2)

  1. Product Information: CYTOVENE-IV(R) IV injection, ganciclovir sodium IV injection. Roche Laboratories Inc, Nutley, NJ, 2008.
  2. Product Information: VALCYTE(R) oral solution, oral tablets, valganciclovir oral solution, oral tablets. Roche Laboratories Inc. Nutley, NJ, 2009. DailyMed
Was this write-up helpful?
Probenecid

Keep reading about Probenecid

All Probenecid interactions (59)
Also serious with: Ketorolac Ketorolac Nasal Spray Mesalamine Ketorolac Ophthalmic
Ganciclovir

Keep reading about Ganciclovir

All Ganciclovir interactions (17) Ganciclovir drug information
Also serious with: Azathioprine Methotrexate Injection Bupropion Clomipramine
Beyond drug–drug

These medications also interact with supplements

Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:

Probenecid + Activated Charcoal Asarabacca Siberian Cocklebur African Wild Potato Aristolochia Banderol Caffeic Acid Coffee Charcoal + 22 more
Ganciclovir + Activated Charcoal Coffee Charcoal European Mandrake Glucomannan Guar Gum Gum Arabic Slippery Elm Tragacanth + 9 more

major · moderate · minor — check everything you take with our drug–supplement interaction checker.

Check another combination

Our instant two-drug interaction checker is almost here.

Coming soon

The instant two-drug checker is on its way.

In the meantime, browse the directory below to look up any drug and see its documented interactions.

Still have questions about this combination?

Every question gets a real answer from a licensed pharmacist — free, and usually within a day.

Ask the pharmacist
This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.