Two medicines, side by side
Sirolimus vs tacrolimus
Sirolimus and tacrolimus are both labeled for organ transplant rejection. Drugs@FDA records approvals of sirolimus since 1999 and of tacrolimus since 1994. Pharmacies paid $0.723 per sirolimus 1 mg tablet and $0.970 per gram (Tacrolimus 0.1% ointment) (NADAC, October 7, 2026); the strengths differ, so the two prices are not like for like. In FDA's classes, sirolimus is a mtor inhibitor immunosuppressant and tacrolimus a calcineurin inhibitor immunosuppressant.
Check it at the source: the sirolimus FDA label on DailyMed (effective January 28, 2026); the tacrolimus FDA label on DailyMed (effective July 17, 2026).
Highlights of the sirolimus record
Sirolimus (Rapamune) · label of January 28, 2026
IMMUNOSUPPRESSION, USE IS NOT RECOMMENDED IN LIVER OR LUNG TRANSPLANT PATIENTS
Increased susceptibility to infection and the possible development of lymphoma and other malignancies may result from immunosuppression Increased susceptibility to infection and the possible development of lymphoma may result from immunosuppression.
Used for
From the label: indicationsSirolimus tablets are an mTOR inhibitor immunosuppressant indicated for the prophylaxis of organ rejection in patients aged ≥13 years receiving renal transplants: ○ Patients at low- to moderate-immunologic risk: Use initially with cyclosporine (CsA) and corticosteroids. […]
On the market
- Earliest approval on file
- September 15, 1999
- Generic labelers
- 17 labelers
- Pharmacy cost
- $0.723 per tablet
Supply and safety
- Shortage
- No current entry
- Recalls
- 5
Highlights of the tacrolimus record
Tacrolimus (Prograf) · label of July 17, 2026
MALIGNANCIES AND SERIOUS INFECTIONS Increased risk for developing serious infections and malignancies with Tacrolimus or other immunosuppressants that may lead to hospitalization or death. ( 5.1 , 5.2 ) WARNING: MALIGNANCIES AND SERIOUS INFECTIONS See full prescribing information for complete boxed warning. Increased risk for developing serious infections and malignancies with tacrolimus or other immunosuppressants that may lead to hospitalization or death.
Used for
From the label: indicationsTacrolimus capsules are a calcineurin-inhibitor immunosuppressant indicated for the prophylaxis of organ rejection in adult and pediatric patients receiving allogeneic liver, kidney or heart transplants, in combination with other immunosuppressants. […]
On the market
- Earliest approval on file
- April 8, 1994
- Generic labelers
- 33 labelers
- Pharmacy cost
- $0.970 per gram
Supply and safety
- Shortage
- No current entry
- Recalls
- 9
Source: FDA drug labels via openFDA (Sirolimus label of January 28, 2026, Tacrolimus label of July 17, 2026); NDC Directory, Drugs@FDA, NADAC, FDA shortages and recalls (October 8, 2026)
How do sirolimus and tacrolimus differ on the record?
In FDA's classes, sirolimus is a mtor inhibitor immunosuppressant and tacrolimus a calcineurin inhibitor immunosuppressant.
Half-life, in each label's words: Sirolimus, “The mean ± SD terminal elimination half-life (t ½ ) of sirolimus after multiple dosing in stable renal transplant …”; Tacrolimus, “Fecal elimination accounted for 92.4±1.0% and the elimination half-life based on radioactivity was 48.1±15.9 hours …”
Both labels carry a boxed warning; the records quote them.
Generics: sirolimus since 2014; tacrolimus since 2009 (Drugs@FDA).
| Sirolimus | Tacrolimus | |
|---|---|---|
| Labeled for | Organ transplant rejection | Organ transplant rejection, Eczema (atopic dermatitis) |
| Pharmacologic class | Kinase Inhibitor, mTOR Inhibitor Immunosuppressant | Calcineurin Inhibitor Immunosuppressant |
| How it works (label) | Sirolimus inhibits T-lymphocyte activation and proliferation that occurs in response to antigenic and cytokine (Interleukin [IL]-2, IL-4, and IL-15) stimulation by a mechanism that is distinct from that of other immunosuppressants. | n/a |
| Half-life (label) | The mean ± SD terminal elimination half-life (t ½ ) of sirolimus after multiple dosing in stable renal transplant patients was estimated to be about 62 ± 16 hours. | Fecal elimination accounted for 92.4±1.0% and the elimination half-life based on radioactivity was 48.1±15.9 hours whereas it was 43.5±11.6 hours based on tacrolimus concentrations. |
| Earliest approval on file (Drugs@FDA) | September 15, 1999 | April 8, 1994 |
| First generic approved | January 8, 2014 | August 10, 2009 |
| Generic labelers (NDC) | 17 labelers | 33 labelers |
| Pharmacy cost (NADAC, each one's most listed form; strengths differ) | $0.723 per tablet (Sirolimus 1 mg tablet) | $0.970 per gram (Tacrolimus 0.1% ointment) |
| 12-month price change | -50% | +3% |
| Boxed warning | Yes | Yes |
| Shortage now | No current entry | No current entry |
| Recalls recorded | 5 | 9 |
| FAERS reports (a report is not proof of cause; counts follow how widely a medicine is used) | 13,365 | 156,020 |
| DEA schedule | none | none |
Source: Drugs@FDA, FDA NDC Directory, CMS NADAC of October 7, 2026, FDA shortages and recalls, FAERS via openFDA (FDA files October 8, 2026)
Do their labels mention each other?
Sirolimus label, boxed warningIn this and another study in de novo liver transplant patients, the use of sirolimus in combination with cyclosporine or tacrolimus was associated with an increase in HAT; most cases of HAT occurred within 30 days post-transplantation and most led to graft loss or death [ see Warnings and Precautions ( 5.2 ) ].
Sirolimus label, warnings and precautionsIn this and another study in de novo liver transplant patients, the use of sirolimus in combination with cyclosporine or tacrolimus was associated with an increase in HAT (7% in combination versus 2% in the control arm); most cases of HAT occurred within 30 days post-transplantation, and most led to graft loss or death.
Tacrolimus label, warnings and precautionsObserve patients receiving tacrolimus injection for signs and symptoms of anaphylaxis. ( 5.9 ) Not recommended for use with sirolimus:
Tacrolimus label, warnings and precautionsNot recommended for use with sirolimus: Not recommended in liver and heart transplant due to increased risk of serious adverse reactions.
Source: FDA drug labels via openFDA
What next?
- Alternatives to sirolimus
- every medicine labeled for the same conditions