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Grapefruit + Tacrolimus

MAJOR — Use With Caution

🔴 AVOID — Tacrolimus has a narrow therapeutic index. Grapefruit inhibits CYP3A4, significantly increasing tacrolimus levels and risking nephrotoxicity. Do not consume grapefruit while on tacrolimus.

Evidence level: STRONG

What this interaction means

Grapefruit can dramatically increase tacrolimus levels. Since tacrolimus has a very narrow safety margin, this can damage your kidneys and cause serious toxicity.

How it works (mechanism)

Grapefruit irreversibly inhibits intestinal CYP3A4, significantly increasing tacrolimus bioavailability. Tacrolimus has a very narrow therapeutic index — small increases cause nephrotoxicity.

Practical advice

Completely avoid grapefruit and grapefruit juice while taking tacrolimus. Even small amounts can cause dangerous level increases. Pomelo and Seville oranges should also be avoided.

Timing

Be consistent with how you take Tacrolimus relative to meals — take it with food or without food consistently each day. Grapefruit — sudden large changes in diet composition can affect how your body processes many medications. Grapefruit, leafy greens, and high-fiber foods are the most common food-drug interaction culprits.

Risk factors

Higher risk for: elderly, those with liver or kidney impairment, polypharmacy (5+ medications), recent medication changes, or those with multiple chronic conditions. Consult your pharmacist for specific risk factors.

Symptoms to watch for

Tremor, headache, nausea, diarrhea, decreased urine output, confusion — signs of tacrolimus toxicity. Contact your transplant team immediately.

What to tell your doctor

No urgent need to discuss, but always keep your doctor informed of your full supplement and medication list. An up-to-date list helps them make the best treatment decisions.

Safer alternatives

Adjust the timing or quantity of Grapefruit relative to your medication. Maintain consistent daily intake rather than large sporadic amounts. Your pharmacist can advise on specific timing windows.

Frequently asked questions

Can I take Grapefruit and Tacrolimus together?

Grapefruit can dramatically increase tacrolimus levels. Since tacrolimus has a very narrow safety margin, this can damage your kidneys and cause serious toxicity.

When should I take Grapefruit vs Tacrolimus?

Be consistent with how you take Tacrolimus relative to meals — take it with food or without food consistently each day. Grapefruit — sudden large changes in diet composition can affect how your body processes many medications. Grapefruit, leafy greens, and high-fiber foods are the most common food-drug interaction culprits.

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

Tremor, headache, nausea, diarrhea, decreased urine output, confusion — signs of tacrolimus toxicity. Contact your transplant team immediately.

Are there safer alternatives to combining Grapefruit with Tacrolimus?

Adjust the timing or quantity of Grapefruit relative to your medication. Maintain consistent daily intake rather than large sporadic amounts. Your pharmacist can advise on specific timing windows.

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

No urgent need to discuss, but always keep your doctor informed of your full supplement and medication list. An up-to-date list helps them make the best treatment decisions.

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