Porfimer and Acetazolamide: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Jul 10, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Acetazolamide
Porfimer
No brand names on record
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.
What happens
Excessive intracellular damage in photosensitized tissues
Interaction Deep Dive
Coadministration of porfimer with other photosensitizing agents (eg, tetracyclines, sulfonamides, phenothiazines, sulfonylurea hypoglycemic agents, thiazide diuretics, griseofulvin, and fluoroquinolones) may increase the risk of a photosensitivity reaction. Some patients may remain photosensitive for up to 90 days or more with porfimer treatment. Avoid the concomitant use of porfimer with other products known to cause photosensitivity1.
Why it happens (mechanism)
Additive photosensitizing effects
Common questions
Can I take Porfimer and Acetazolamide together?
Excessive intracellular damage in photosensitized tissues Always confirm with your pharmacist or prescriber before making any change.
How serious is the Porfimer and Acetazolamide interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Porfimer or Acetazolamide 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 a safer alternative to one of these medications for me?
References (1)
- Product Information: PHOTOFRIN(R) intravenous injection, porfimer sodium intravenous injection. Pinnacle Biologics, Inc. (per FDA), Bannockburn, IL, 2019. DailyMed
Keep reading about Acetazolamide
Keep reading about Porfimer
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