Prograf (tacrolimus) is an immunosuppressant medicine used to prevent rejection of transplanted organs, including kidney, liver, heart, and other organ transplants. It is also used to treat organ rejection when it occurs.

Tacrolimus belongs to a class called calcineurin inhibitors. It works by blocking calcineurin, an enzyme that activates T-lymphocytes (the main immune cells responsible for attacking the transplanted organ). By suppressing these cells, tacrolimus prevents the immune system from rejecting the transplant.

Prograf capsules are taken twice daily, at the same times each day (usually 12 hours apart), consistently either with or without food. Changing your food habits can affect absorption.

Swallow capsules whole. Do not open, crush, or chew them.

Do not eat grapefruit or drink grapefruit juice. Grapefruit increases tacrolimus levels significantly and can cause toxicity.

Blood levels are checked regularly. Your doctor will adjust the dose to keep levels within a specific target range. Never adjust the dose yourself.

There are different tacrolimus products (Prograf, Advagraf, generic tacrolimus) that are not all interchangeable. Always take the specific product your transplant team has prescribed and do not switch without advice.

Contact your transplant team for advice. Missing tacrolimus doses can allow rejection to begin. As a general guide, if you remember within a few hours of the usual time, take it then. If it is nearly time for your next dose, do not double up. Always inform your transplant team of missed doses.

Seek urgent medical attention. Tacrolimus toxicity can cause kidney damage, neurological symptoms (tremor, confusion, seizures), and high blood pressure. Blood levels can confirm toxicity.

• Store below 25°C
• Keep in the original blister pack or container
• Protect from moisture and light
• Keep out of reach of children

Side effects are very common with tacrolimus, many relating to its immune-suppressing or direct toxic effects.

Very common side effects:

• Kidney problems (nephrotoxicity): the main long-term toxicity concern. Creatinine and kidney function are monitored closely
• High blood pressure: extremely common, often requiring medicine
• Tremor (shakiness): particularly of the hands, especially at higher levels
• Insomnia
• Headache
• Raised blood sugar or new-onset diabetes (post-transplant diabetes mellitus): more common with tacrolimus than ciclosporin

Common side effects:

• Infections: as with all immunosuppressants, the risk of bacterial, viral, fungal, and opportunistic infections is elevated

Serious side effects:

• Neurotoxicity at high levels: confusion, seizures, posterior reversible encephalopathy syndrome (PRES)
• Skin cancer and lymphoma with long-term immunosuppression

Blood trough levels (taken just before the morning dose) are checked regularly and used to adjust your dose.

Tacrolimus has very many interactions.

Key ones include:

• Grapefruit juice: avoid completely. Significantly increases tacrolimus levels
• Antifungals (fluconazole, voriconazole, itraconazole, ketoconazole): dramatically increase tacrolimus levels
• Macrolide antibiotics (clarithromycin, erythromycin): increase tacrolimus levels
• Rifampicin, St John's Wort, carbamazepine, phenytoin: dramatically reduce tacrolimus levels, risking rejection
• NSAIDs (ibuprofen, naproxen): increase kidney toxicity risk

Always tell every healthcare provider that you are on tacrolimus. Never start a new medicine without checking for interactions first.

How do I know if my tacrolimus level is right?

Your transplant team will measure a trough blood level (taken just before your morning dose) and compare it to your target range. This range varies depending on how long it has been since your transplant and your individual risk of rejection. In the first weeks after transplant, levels need to be higher; they are often reduced over time as the risk of rejection decreases. Keeping levels too low risks rejection; keeping them too high causes toxicity.

Why can't I switch brands?

Different tacrolimus products (immediate-release Prograf, once-daily Advagraf, and generic tacrolimus) have different absorption profiles. Even subtle changes in blood levels can trigger rejection or cause toxicity in transplant patients. If a switch becomes necessary, it requires careful dose adjustment and level monitoring under specialist supervision.

Ace provides accurate and independent information medically reviewed on prescription medications. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment.