What is the generic version of tacrolimus?

October 6, 2025 •

4 min read

The active ingredient in the brand-name drug Prograf is tacrolimus, which is also the generic name for the drug itself. Understanding what is the generic version of tacrolimus? is vital for transplant patients managing their medication and associated costs.

Quick Summary

Tacrolimus is the generic version of the immunosuppressant medication, an active ingredient also sold under brand names like Prograf. Generic formulations are often more affordable and considered bioequivalent, but switching from a brand version must be done with careful medical supervision and monitoring of blood levels. It works by suppressing the immune system to prevent organ rejection and is also used for eczema.

Key Points

Generic Name: The generic version of the brand-name drug Prograf is tacrolimus.
Immunosuppressant: Tacrolimus is an immunosuppressive drug used to prevent organ rejection after a transplant and to treat eczema.
Bioequivalence: Generic tacrolimus is considered bioequivalent to brand-name drugs, but close monitoring is required, especially after switching.
Not Interchangeable: Different formulations (immediate-release, extended-release, topical) of tacrolimus are not interchangeable and must be taken exactly as prescribed.
Patient Monitoring: Regular blood tests are essential to maintain stable tacrolimus levels and prevent organ rejection or toxicity.
Food and Drug Interactions: Patients must avoid grapefruit and be cautious with many other medications and supplements to prevent dangerous interactions.
Common Side Effects: Common side effects include tremors, headache, and gastrointestinal issues, while more serious risks involve infection and certain cancers.

Understanding Generic Tacrolimus

Tacrolimus is a powerful immunosuppressant medication belonging to a class of drugs known as calcineurin inhibitors. The generic drug, tacrolimus, is an exact copy of the active ingredient in its brand-name counterparts and is considered by the U.S. Food and Drug Administration (FDA) to be just as safe and effective. The most well-known brand names for tacrolimus include Prograf®, Astagraf XL®, Envarsus XR®, and Protopic®. These different products can come in various formulations and are used for slightly different purposes, such as preventing organ rejection after a transplant or treating atopic dermatitis (eczema).

The Role of Tacrolimus in Transplant Medicine

When a person receives an organ transplant, their body's immune system will recognize the new organ as a foreign object and attempt to attack and reject it. As an immunosuppressant, tacrolimus works by weakening the body's immune response to help it accept the new organ. This is a crucial, lifelong treatment for transplant recipients to ensure the long-term success of their new organ. The medication is also available as a topical ointment (Protopic®) used to treat moderate to severe atopic dermatitis (eczema) by suppressing the immune response in the skin.

Formulations and Dosage

Tacrolimus is available in several forms, which are not interchangeable due to differences in how the body absorbs and processes them. Your healthcare provider will prescribe the specific formulation that is right for you, and you must not switch without their approval.

Immediate-Release Capsules (Generic Tacrolimus and Prograf®): These are typically taken twice daily, 12 hours apart.
Extended-Release Capsules (Astagraf XL® and Envarsus XR®): These are longer-acting forms, usually taken once a day.
Granules for Oral Suspension (Prograf®): This form is available for patients, particularly children, who have difficulty swallowing capsules.
Topical Ointment (Protopic®): This is applied directly to the skin for eczema treatment.

Generic vs. Brand-Name: What to Know Before Switching

While generic drugs are bioequivalent to their brand-name counterparts, there can be subtle differences in how a person's body responds. For a medication with a narrow therapeutic index like tacrolimus, small variations in blood levels can have significant consequences.

Bioequivalence vs. Clinical Equivalence: Bioequivalence is proven in healthy volunteers, but in stable transplant patients, some studies have shown slight variations in tacrolimus trough levels after converting from brand-name Prograf to generic tacrolimus. This highlights why monitoring is crucial.
FDA Scrutiny: Concerns from the transplant community have led the FDA to investigate the substitutability of certain generic tacrolimus products, leading to a therapeutic equivalence rating change for one manufacturer's capsules. This demonstrates the importance of receiving medication from a reputable, validated pharmacy.

Comparison of Generic Tacrolimus vs. Brand-Name Prograf


Feature	Generic Tacrolimus	Brand-Name Prograf®
Active Ingredient	Tacrolimus	Tacrolimus
Cost	Typically lower cost	Higher cost
Forms	Immediate-release capsules	Immediate-release capsules, granules for oral suspension
Interchangeability	Not interchangeable with other formulations without doctor's approval	Not interchangeable with other formulations without doctor's approval
Clinical Data	Multiple manufacturers, bioequivalence demonstrated in healthy volunteers; real-world data shows some variation possible	Extensive clinical history since 1994, used as the reference drug for bioequivalence
Monitoring	Requires consistent blood level monitoring, especially after switching	Requires consistent blood level monitoring

Common Side Effects of Tacrolimus

Taking tacrolimus carries the risk of certain side effects. Many are manageable, but some can be serious. It is crucial to inform your doctor about any new or worsening symptoms.

Common Side Effects:
- Tremors or shaking
- Headache
- Diarrhea, nausea, and vomiting
- High blood pressure (hypertension)
- Kidney problems, indicated by changes in urination
- Increased blood sugar, which can lead to diabetes
Serious Risks:
- Increased risk of infection: As an immunosuppressant, tacrolimus lowers your ability to fight infections.
- Increased risk of cancer: Long-term use is associated with a higher risk of certain cancers, such as skin and lymph gland cancer.
- Neurological problems: Can cause delirium, seizures, or confusion.
- Heart problems: Including heart rhythm changes (QT prolongation).

Important Considerations and Safety Precautions

Managing tacrolimus effectively involves more than just remembering to take your dose. Here are some key points to ensure safe and effective treatment:

Avoid Grapefruit: Consumption of grapefruit or grapefruit juice can dangerously increase the levels of tacrolimus in your body.
Tell Your Doctor About Other Medications: Many medications and herbal supplements, including St. John's wort and certain antifungals, can interact with tacrolimus and affect its levels. Always provide a comprehensive list to your healthcare team.
Consistent Dosing: Take your medication at the same time each day, as directed. For immediate-release capsules, maintaining consistency with food (either always with or always without) is important for stable blood levels.
Regular Monitoring: Routine blood tests are essential to ensure your tacrolimus levels remain within the optimal therapeutic range.
Sun Protection: Due to the increased risk of skin cancer, patients taking tacrolimus should limit sun exposure, wear protective clothing, and use sunscreen.
No Live Vaccines: Avoid live vaccines while on immunosuppressants.

Conclusion

For those needing immunosuppressive therapy, understanding what is the generic version of tacrolimus? is a critical first step. The generic drug, tacrolimus, provides a reliable and cost-effective alternative to brand-name medications like Prograf. However, due to its narrow therapeutic index and the potential for variations in absorption, switching between generic and brand-name formulations should only be undertaken under strict medical supervision and with careful monitoring of blood levels. Adherence to a consistent regimen, awareness of side effects, and vigilance regarding drug and food interactions are all paramount for the safety and long-term success of the patient's treatment.

Disclaimer: This article is for informational purposes only and is not a substitute for professional medical advice. Always consult with your doctor or transplant team regarding your specific treatment plan.

Frequently Asked Questions

Yes, generic tacrolimus is considered just as safe and effective as brand-name Prograf because it contains the identical active ingredient and must meet the same bioequivalence standards set by the FDA.

Tacrolimus has a narrow therapeutic index, meaning there is a small margin between an effective dose and a toxic dose. Monitoring blood levels ensures the concentration stays within a safe range to prevent organ rejection (if too low) or adverse side effects (if too high).

You should never switch between different tacrolimus products, including different generic manufacturers or between immediate-release and extended-release versions, without consulting your doctor. Different formulations are not interchangeable and can alter drug levels in your body.

Common side effects include tremors, headache, diarrhea, nausea, high blood pressure, and kidney problems. Many patients also experience insomnia and changes in electrolyte levels.

You must avoid grapefruit and grapefruit juice while taking tacrolimus. Grapefruit significantly increases the absorption of tacrolimus, which can lead to dangerously high blood levels and severe side effects.

Yes, tacrolimus ointment is the generic version of the brand-name topical medication Protopic®, which is used to treat moderate to severe atopic dermatitis (eczema).

The FDA issued a concern and changed the therapeutic equivalence rating for Accord Healthcare Inc.'s generic tacrolimus oral capsules due to findings suggesting it may deliver a higher peak concentration of the drug compared to Prograf. This emphasizes the need for close monitoring when switching products.

Missing a dose can cause tacrolimus levels to drop, increasing the risk of organ rejection. It is very important to take the medication consistently. If a dose is missed, contact your healthcare provider immediately for instructions, as the timing for making up a dose varies by formulation.