Tacrolimus has many serious drug interactions. Learn which medications, supplements, and foods to avoid and what to tell your doctor before starting.
Tacrolimus has a narrow therapeutic window — meaning the difference between too little and too much in your blood is very small. Too little Tacrolimus puts your transplanted organ at risk of rejection. Too much can cause serious side effects like kidney damage, seizures, and dangerously high potassium levels.
Because of this, anything that raises or lowers Tacrolimus levels in your blood can be dangerous. That includes prescription medications, over-the-counter drugs, supplements, and even certain foods. This guide covers the most important interactions you need to know about.
Tacrolimus is processed (metabolized) primarily by a liver enzyme called CYP3A4. Drugs that affect this enzyme can dramatically change how much Tacrolimus stays in your blood:
Other interactions occur because of additive effects — for example, combining Tacrolimus with another drug that damages the kidneys doubles the risk of kidney problems.
These interactions can be dangerous and may require dose changes, additional monitoring, or avoidance entirely:
These medications can significantly increase the amount of Tacrolimus in your blood, raising the risk of kidney damage, neurotoxicity, and other serious side effects:
If your doctor prescribes one of these, they'll likely reduce your Tacrolimus dose and monitor your blood levels more frequently.
These medications speed up the breakdown of Tacrolimus, potentially dropping your levels below what's needed to protect your transplant:
Do not take Tacrolimus and Cyclosporine together. Both are calcineurin inhibitors that affect the kidneys. Combining them dramatically increases the risk of severe kidney damage. If switching from one to the other, your doctor will ensure a washout period between them.
Because Tacrolimus suppresses your immune system, live vaccines should be avoided. Your weakened immune system may not be able to fight the live virus in the vaccine, potentially causing the disease it's meant to prevent. Examples include:
Inactivated vaccines (like the flu shot or COVID vaccines) are generally safe and recommended. Talk to your transplant team about your vaccination schedule.
Combining Tacrolimus with other drugs that can harm the kidneys increases your risk of kidney damage:
Tacrolimus can raise potassium levels on its own. Combining it with other potassium-raising drugs can lead to dangerously high levels (hyperkalemia):
These may require monitoring or dose adjustments but are sometimes used together when the benefit outweighs the risk:
Don't assume that "natural" or "over-the-counter" means safe with Tacrolimus:
This popular herbal supplement for depression is a strong CYP3A4 inducer. It can dramatically lower Tacrolimus levels and put your transplant at risk. Avoid completely.
Over-the-counter pain relievers like Advil (Ibuprofen) and Aleve (Naproxen) can damage the kidneys, and combining them with Tacrolimus increases this risk. Ask your doctor about safer alternatives for pain — Acetaminophen (Tylenol) is generally preferred, but check with your transplant team first.
Since Tacrolimus can raise potassium levels, avoid potassium supplements or potassium-rich salt substitutes unless your doctor specifically tells you to take them.
On the flip side, Tacrolimus can lower magnesium levels. Your doctor may actually prescribe magnesium supplements, which is fine when monitored.
Avoid completely. Grapefruit inhibits CYP3A4 in your gut, which can significantly increase Tacrolimus blood levels. This applies to whole grapefruit, grapefruit juice, and other citrus fruits like Seville oranges and pomelos that have similar effects.
Avoid, especially with extended-release formulations (Envarsus XR, Astagraf XL). Alcohol can increase the rate of drug release, potentially causing a dangerous spike in Tacrolimus levels.
High-fat meals may decrease absorption of some Tacrolimus formulations. The key is consistency — take your medication the same way every day, whether with or without food. Don't alternate between fasting and large meals at dosing time.
Before starting Tacrolimus — and at every follow-up — make sure your doctor and pharmacist know about:
It helps to keep an updated medication list on your phone or in your wallet. Show it to every healthcare provider you see.
Tacrolimus interacts with a wide range of medications, supplements, and foods. Because of its narrow therapeutic window, even small changes in blood levels can be clinically significant. The most important things you can do are: keep your medication list current, avoid grapefruit and St. John's Wort, check before taking any new medication (even OTC), and never miss your blood level monitoring appointments.
For more about how Tacrolimus works, its side effects, or how to save money on your prescription, explore our Tacrolimus guides. And if you need help finding it in stock, Medfinder can help.
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