⚠️

Fluconazole + Tacrolimus

MAJOR — Use With Caution

FDA-documented interaction. Tacrolimus dose reduction typically needed. Frequent tacrolimus level and renal function monitoring required.

Evidence level: STRONG

What this interaction means

Fluconazole (Diflucan) can dramatically increase tacrolimus (Prograf) levels in your blood. Since tacrolimus has a very narrow safety margin and can damage kidneys, this is a dangerous combination that requires close monitoring.

How it works (mechanism)

Fluconazole inhibits CYP3A4 and CYP2C9. Tacrolimus is primarily metabolized by CYP3A4. Fluconazole significantly increases tacrolimus levels, risking nephrotoxicity. FDA tacrolimus label warns about azole antifungals.

Practical advice

If you take tacrolimus (an anti-rejection medication) and need fluconazole, your doctor should reduce your tacrolimus dose and check blood levels frequently. Report any changes in urination or kidney pain.

Timing

Take Fluconazole as directed (some require food for absorption, others an empty stomach — check the label). Azole antifungals are potent CYP enzyme inhibitors that can dramatically increase blood levels of many medications. Tacrolimus levels should be monitored during antifungal treatment.

Risk factors

Higher risk for: those with liver impairment (azole antifungals are hepatotoxic), concurrent CYP3A4 substrate use, elderly, renal impairment, or those on multiple QT-prolonging medications.

Symptoms to watch for

Decreased urination, swelling in hands/feet, tremor, headache, nausea, confusion, high blood pressure, elevated creatinine (found on blood tests)

What to tell your doctor

Request tacrolimus level monitoring within 3-5 days of starting fluconazole. Plan preemptive dose reduction. Monitor renal function (creatinine, BUN).

Safer alternatives

Azole antifungals are potent CYP enzyme inhibitors. Ask your doctor about topical antifungal options to avoid systemic interactions, or about terbinafine which has fewer drug interactions than azoles.

Frequently asked questions

Can I take Fluconazole and Tacrolimus together?

Fluconazole (Diflucan) can dramatically increase tacrolimus (Prograf) levels in your blood. Since tacrolimus has a very narrow safety margin and can damage kidneys, this is a dangerous combination that requires close monitoring.

When should I take Fluconazole vs Tacrolimus?

Take Fluconazole as directed (some require food for absorption, others an empty stomach — check the label). Azole antifungals are potent CYP enzyme inhibitors that can dramatically increase blood levels of many medications. Tacrolimus levels should be monitored during antifungal treatment.

What symptoms should I watch for if I combine Fluconazole and Tacrolimus?

Decreased urination, swelling in hands/feet, tremor, headache, nausea, confusion, high blood pressure, elevated creatinine (found on blood tests)

Are there safer alternatives to combining Fluconazole with Tacrolimus?

Azole antifungals are potent CYP enzyme inhibitors. Ask your doctor about topical antifungal options to avoid systemic interactions, or about terbinafine which has fewer drug interactions than azoles.

What should I tell my doctor about taking Fluconazole and Tacrolimus?

Request tacrolimus level monitoring within 3-5 days of starting fluconazole. Plan preemptive dose reduction. Monitor renal function (creatinine, BUN).

Explore more interactions

Or browse the full interaction database (121,000+ pairs).