Didanosine and Itraconazole: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Itraconazole
Didanosine
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
Decreased itraconazole effectiveness
Interaction Deep Dive
The bioavailability of oral itraconazole may be decreased during coadministration with oral didanosine34. If itraconazole and didanosine are coprescribed, itraconazole should be administered at least two hours before didanosine 61.
Why it happens (mechanism)
Decreased itraconazole absorption due to increased gastrointestinal pH
Literature reports
3 reports — tap to read
a) Single doses of oral didanosine 300 mg and oral itraconazole 200 mg were administered to six healthy volunteers in a randomized, crossover study 3. Mean peak serum concentration was 0.9 mcg/mL and mean time to peak was three hours when itraconazole alone was given. With concomitant didanosine and itraconazole, concentrations of itraconazole were undetectable (less than 0.5 mcg/mL) in all six subjects. The mechanism of action was considered to be reduced gastric absorption. The limited solubility of itraconazole (only soluble in extremely acid solutions) is reduced by magnesium and aluminum buffers in didanosine tablets (Bristol-Myers Squibb).
b) A 35-year old man had reduced itraconazole absorption while taking didanosine. The patient had successfully completed primary therapy for cryptococcal meningitis, and began taking itraconazole 200 mg twice daily in a blinded evaluation. Two months later, the patient was switched from zidovudine to didanosine 200 mg twice daily for continued anemia. Three months later, a positive cerebrospinal fluid culture for cryptococcus neoformans confirmed relapse of the infection. The patient was then given 600 mg itraconazole concurrently with 200 mg chewable didanosine, and serial plasma samples were taken over the next 24 hours. The following day, 600 mg itraconazole was administered alone. Itraconazole absorption was dramatically delayed when administered with didanosine. Two hours after coadministration, itraconazole levels were undetectable, with a peak concentration of 1.4 mcg/mL occurring eight hours after the dose was given. Two hours after itraconazole was given alone, a peak concentration of 1.6 mcg/mL was observed. The authors concluded that concurrent administration of these two agents should be avoided until further studies can better define the interaction 4.
c) Antacids raise the pH in the stomach, thus are predicted to alter Itraconazole plasma concentration5. Didanosine pediatric powder is reconstituted to final volume using water and antacid. Itraconazole should be administered two hours before didanosine to prevent malabsorption of itraconazole1.
Common questions
Can I take Didanosine and Itraconazole together?
Decreased itraconazole effectiveness Always confirm with your pharmacist or prescriber before making any change.
How serious is the Didanosine and Itraconazole interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Didanosine or Itraconazole 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 (6)
- Product Information: VIDEX(R) pediatric powder for oral solution, didanosine pediatric powder for oral solution. Bristol-Myers Squibb Company, Princeton, NJ, 2009.
- Product Information: Videx(R), didanosine. Bristol-Myers Squibb Company, Princeton, NJ, 1999. DailyMed
- May DB, Drew RH, Yedinak KC, et al: Effect of simultaneous didanosine administration on itraconazole absorption in healthy volunteers. Pharmacotherapy 1994; 14:509-513. DOI
- Moreno F, Hardin TC, Rinaldi MG, et al: Itraconazole-didanosine excipient interaction (letter). JAMA 1993; 269:1508. DOI
- Product Information: SPORANOX(R) oral solution, itraconazole oral solution. Janssen, Raritan, NJ, 2009. DailyMed
- Product Information: Videx(R), didanosine. Bristol-Myers Squibb Company, Princeton, NJ, 1999. DailyMed
Keep reading about Itraconazole
Keep reading about Didanosine
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:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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