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Quick facts
- Drug class
- mTOR Inhibitor Immunosuppressant [EPC], Kinase Inhibitor [EPC], mTOR Inhibitors [MoA], Protein Kinase Inhibitors [MoA]
- How it is given
- oral
- Type
- human prescription drug
- RxNorm ID
- 905158
We do not publish dosing. How much of this medicine to take, how often, and for how long depends on your age, weight, kidney and liver function, other conditions and other medicines. That is a decision for the person who prescribes or dispenses it. Follow the directions on your own pack and ask your pharmacist if anything is unclear.
What it is used to treat
Sirolimus is 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. CsA withdrawal is recommended 2 months to 4 months after transplantation ( 1.1 ). Patients at high-immunologic risk: Use in combination with CsA and corticosteroids for the first 12 months following transplantation (1.1). Safety and efficacy of CsA withdrawal has not been established in high risk patients ( 1.1 , 1.2 , 14.3 ). Sirolimus is an mTOR inhibitor indicated for the treatment of patients with lymphangioleiomyomatosis ( 1.3 ). 1.1 Prophylaxis of Organ Rejection in Renal Transplantation Sirolimus tablets are indicated for the prophylaxis of organ rejection in patients aged 13 years or older receiving renal transplants. In patients at low- to moderate-immunologic risk, it is recommended that sirolimus tablets be used initially in a regimen with cyclosporine and corticosteroids; cyclosporine should be withdrawn 2 to 4 months after transplantation [ see Dosage and Administration ( 2.2 ) ]. In patients at high-immunologic risk (defined as Black recipients and/or repeat renal transplant recipients who lost a previous allograft for immunologic reason and/or patients with high panel-reactive antibodies [PRA; peak PRA level > 80%]), it is recommended that sirolimus tablets be used in combination with cyclosporine and corticosteroids for the first year following transplantation [ see Dosage and Administration ( 2.3 ), Clinical Studies ( 14.3 ) ]. 1.2 Limitations of Use in Renal Transplantation Cyclosporine withdrawal has not been studied in patients with Banff Grade 3 acute rejection or vascular rejection prior to cyclosporine withdrawal, those who are dialysis-dependent, those with serum creatinine > 4.5 mg/dL, Black patients, patients of multi-organ transplants, secondary transplants, or those with high levels of panel-reactive antibodies [ see Clinical Studies ( 14.2 ) ]. […]
About this medicine
Sirolimus is an mTOR inhibitor immunosuppressive agent. Sirolimus is a macrocyclic lactone produced by Streptomyces hygroscopicus . The chemical name of sirolimus (also known as rapamycin) is (3 S ,6 R ,7 E ,9 R ,10 R ,12 R ,14 S ,15 E ,17 E ,19 E ,21 S ,23 S ,26 R ,27 R ,34a S )-9,10,12,13,14,21,22,23,24,25,26,27,32,33,34,34a-hexadecahydro-9,27-dihydroxy-3-[(1 R )-2-[(1 S ,3 R ,4 R )-4-hydroxy-3-methoxycyclohexyl]-1-methylethyl]-10,21-dimethoxy-6,8,12,14,20,26-hexamethyl-23,27-epoxy-3 H -pyrido[2,1-c][1,4] oxaazacyclohentriacontine-1,5,11,28,29 (4 H ,6 H ,31 H )-pentone. Its molecular formula is C 51 H 79 NO 13 and its molecular weight is 914.2. The structural formula of sirolimus is illustrated as follows. Sirolimus is a white to off-white powder and is insoluble in water, but freely soluble in benzyl alcohol, chloroform, acetone, and acetonitrile. Each sirolimus tablet intended for oral administration contains 0.5 mg or 1 mg or 2 mg of sirolimus. In addition, each tablet contains the following inactive ingredients: citric acid monohydrate, crospovidone, glyceryl monooleate, hypromellose, lactose monohydrate, microcrystalline cellulose, poloxamer, polyethylene glycol, povidone, sucrose, talc, titanium dioxide and vitamin E acetate. Additionally, each 0.5 mg tablet contains FD&C yellow #5 Aluminum Lake and iron oxide yellow and 2 mg tablet contains iron oxide black, iron oxide red and iron oxide yellow. Image
How it works
12.1 Mechanism of Action 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. Sirolimus also inhibits antibody production. In cells, sirolimus binds to the immunophilin, FK Binding Protein-12 (FKBP-12), to generate an immunosuppressive complex. The sirolimus:FKBP-12 complex has no effect on calcineurin activity. This complex binds to and inhibits the activation of the mammalian target of rapamycin (mTOR), a key regulatory kinase. This inhibition suppresses cytokine-driven T-cell proliferation, inhibiting the progression from the G 1 to the S phase of the cell cycle. Mammalian target of rapamycin (mTOR) inhibitors such as sirolimus have been shown in vitro to inhibit production of certain growth factors that may affect angiogenesis, fibroblast proliferation, and vascular permeability. Studies in experimental models show that sirolimus prolongs allograft (kidney, heart, skin, islet, small bowel, pancreatico-duodenal, and bone marrow) survival in mice, rats, pigs, and/or primates. Sirolimus reverses acute rejection of heart and kidney allografts in rats and prolongs the graft survival in presensitized rats. In some studies, the immunosuppressive effect of sirolimus lasts up to 6 months after discontinuation of therapy. This tolerization effect is alloantigen-specific. In rodent models of autoimmune disease, sirolimus suppresses immune-mediated events associated with systemic lupus erythematosus, collagen-induced arthritis, autoimmune type I diabetes, autoimmune myocarditis, experimental allergic encephalomyelitis, graft-versus-host disease, and autoimmune uveoretinitis. Lymphangioleiomyomatosis involves lung tissue infiltration with smooth muscle-like cells that harbor inactivating mutations of the tuberous sclerosis complex (TSC) gene (LAM cells). Loss of TSC gene function activates the mTOR signaling pathway, resulting in cellular proliferation and release of lymphangiogenic growth factors. Sirolimus inhibits the activated mTOR pathway and thus the proliferation of LAM cells.
Who should not take it
Sirolimus is contraindicated in patients with a hypersensitivity to sirolimus [ see Warnings and Precautions ( 5.4 ) ]. Hypersensitivity to sirolimus ( 4 ).
Warnings and cautions
Hypersensitivity Reactions ( 5.4 ) Angioedema ( 5.5 ) Fluid Accumulation and Impairment of Wound Healing ( 5.6 ) Hyperlipidemia ( 5.7 ) Decline in Renal Function ( 5.8 ) Proteinuria ( 5.9 ) Latent Viral Infections ( 5.10 ) Interstitial Lung Disease/Non-Infectious Pneumonitis ( 5.11 ) De Novo Use Without Cyclosporine ( 5.12 ) Increased Risk of Calcineurin Inhibitor-Induced Hemolytic Uremic Syndrome/ Thrombotic Thrombocytopenic Purpura/ Thrombotic Microangiopathy ( 5.13 ) Embryo-Fetal Toxicity: Can cause fetal harm. Use of highly effective contraception is recommended for females of reproductive potential during treatment and for 12 weeks after final dose of sirolimus ( 5.15 , 8.1 ) Male Infertility: Azoospermia or oligospermia may occur ( 5.16 , 13.1 ) Immunizations: Avoid live vaccines ( 5.19 ) 5.1 Increased Susceptibility to Infection and the Possible Development of Lymphoma Increased susceptibility to infection and the possible development of lymphoma and other malignancies, particularly of the skin, may result from immunosuppression. The rates of lymphoma/lymphoproliferative disease observed in Studies 1 and 2 were 0.7 to 3.2% (for sirolimus-treated patients) versus 0.6 to 0.8% (azathioprine and placebo control) [ see Adverse Reactions ( 6.1 ) and ( 6.2 ) ]. Oversuppression of the immune system can also increase susceptibility to infection, including opportunistic infections such as tuberculosis, fatal infections, and sepsis. Only physicians experienced in immunosuppressive therapy and management of organ transplant patients should use sirolimus for prophylaxis of organ rejection in patients receiving renal transplants. Patients receiving the drug should be managed in facilities equipped and staffed with adequate laboratory and supportive medical resources. The physician responsible for maintenance therapy should have complete information requisite for the follow-up of the patient. 5.2 Liver Transplantation - Excess Mortality, Graft Loss, and Hepatic Artery Thrombosis The safety and efficacy of sirolimus as immunosuppressive therapy have not been established in liver transplant patients; therefore, such use is not recommended. […]
Reported side effects
The following adverse reactions are discussed in greater detail in other sections of the label. Increased susceptibility to infection, lymphoma, and malignancy [ see Boxed Warning, Warnings and Precautions ( 5.1 ) ] Excess mortality, graft loss, and hepatic artery thrombosis in liver transplant patients [ see Boxed Warning, Warnings and Precautions ( 5.2 ) ] Bronchial anastomotic dehiscence in lung transplant patients [ see Boxed Warning, Warnings and Precautions ( 5.3 ) ] Hypersensitivity reactions [ see Warnings and Precautions ( 5.4 ) ] Exfoliative dermatitis [ see Warnings and Precautions ( 5.4 ) ] Angioedema [ see Warnings and Precautions ( 5.5 ) ] Fluid accumulation and impairment of wound healing [ see Warnings and Precautions ( 5.6 ) ] Hypertriglyceridemia, hypercholesterolemia [ see Warnings and Precautions ( 5.7 ) ] Decline in renal function in long-term combination of cyclosporine with sirolimus [ see Warnings and Precautions ( 5.8 ) ] Proteinuria [ see Warnings and Precautions ( 5.9 ) ] Interstitial lung disease [ see Warnings and Precautions ( 5.11 ) ] Increased risk of calcineurin inhibitor-induced HUS/TTP/TMA [ see Warnings and Precautions ( 5.13 ) ] Embryo-fetal toxicity [see Warnings and Precautions ( 5.15 )] Male infertility [see Warnings and Precautions ( 5.16 )] The most common (≥ 30%) adverse reactions observed with sirolimus in clinical studies for organ rejection prophylaxis in recipients of renal transplantation are: peripheral edema, hypertriglyceridemia, hypertension, hypercholesterolemia, creatinine increased, constipation, abdominal pain, diarrhea, headache, fever, urinary tract infection, anemia, nausea, arthralgia, pain, and thrombocytopenia. The most common (≥20%) adverse reactions observed with sirolimus in the clinical study for the treatment of LAM are: stomatitis, diarrhea, abdominal pain, nausea, nasopharyngitis, acne, chest pain, peripheral edema, upper respiratory tract infection, headache, dizziness, myalgia, and hypercholesterolemia. […]
Interactions with other medicines
Sirolimus is known to be a substrate for both cytochrome P-450 3A4 (CYP3A4) and p-glycoprotein (P-gp). Inducers of CYP3A4 and P-gp may decrease sirolimus concentrations whereas inhibitors of CYP3A4 and P-gp may increase sirolimus concentrations. Avoid concomitant use with strong CYP3A4/P-gp inducers or strong CYP3A4/P-gp inhibitors that decrease or increase sirolimus concentrations ( 7.4 , 12.3 ). Therapeutic drug monitoring and dose reduction for sirolimus should be considered when sirolimus is co-administered with cannabidiol ( 5.21 , 7.5 ). See full prescribing information for complete list of clinically significant drug interactions ( 12.3 ). 7.1 Use with Cyclosporine Cyclosporine, a substrate and inhibitor of CYP3A4 and P-gp, was demonstrated to increase sirolimus concentrations when coadministered with sirolimus. In order to diminish the effect of this interaction with cyclosporine, it is recommended that sirolimus be taken 4 hours after administration of cyclosporine oral solution (MODIFIED) and/or cyclosporine capsules (MODIFIED). If cyclosporine is withdrawn from combination therapy with sirolimus, higher doses of sirolimus are needed to maintain the recommended sirolimus trough concentration ranges [ see Dosage and Administration ( 2.2 ), Clinical Pharmacology ( 12.3 ) ]. 7.2 Strong Inducers and Strong Inhibitors of CYP3A4 and P-gp Avoid concomitant use of sirolimus with strong inducers (e.g., rifampin, rifabutin) and strong inhibitors (e.g., ketoconazole, voriconazole, itraconazole, erythromycin, telithromycin, clarithromycin) of CYP3A4 and P-gp. Alternative agents with lesser interaction potential with sirolimus should be considered [ see Warnings and Precautions ( 5.20 ), Clinical Pharmacology ( 12.3 ) ]. 7.3 Grapefruit Juice Because grapefruit juice inhibits the CYP3A4-mediated metabolism of sirolimus, it must not be taken with or be used for dilution of sirolimus [ see Drug Interactions ( 7.3 ), Clinical Pharmacology ( 12.3 ) ]. 7.4 Weak and Moderate Inducers or Inhibitors of CYP3A4 and P-gp Exercise caution when using sirolimus with drugs or agents that are modulators of CYP3A4 and P-gp. […]
Use in specific groups
Pregnancy: Based on animal data can cause fetal harm ( 5.15 , 8.1 ). Lactation: Potential for serious adverse effects in breastfed infants based on mechanism of action ( 8.2 ). Females and Males of Reproductive Potential: May impair fertility ( 8.1 , 8.3 , 13.1 ). 8.1 Pregnancy Risk Summary Based on animal studies and the mechanism of action, sirolimus can cause fetal harm when administered to a pregnant woman [see Data, Clinical Pharmacology ( 12.1 )] . There are limited data on the use of sirolimus during pregnancy; however, these data are insufficient to inform a drug-associated risk of adverse developmental outcomes. In animal studies, sirolimus was embryo/fetotoxic in rats at sub-therapeutic doses [ see Data ]. Advise pregnant women of the potential risk to a fetus. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. Data Animal Data Sirolimus crossed the placenta and was toxic to the conceptus. In rat embryo-fetal development studies, pregnant rats were administered sirolimus orally during the period of organogenesis (Gestational Day 6 to 15). Sirolimus produced embryo-fetal lethality at 0.5 mg/kg (2.5-fold the clinical dose of 2 mg, on a body surface area basis) and reduced fetal weight at 1 mg/kg (5-fold the clinical dose of 2 mg). The no observed adverse effect level (NOAEL) for fetal toxicity in rats was 0.1 mg/kg (0.5-fold the clinical dose of 2 mg). Maternal toxicity (weight loss) was observed at 2 mg/kg (10-fold the clinical dose of 2 mg). The NOAEL for maternal toxicity was 1 mg/kg. In combination with cyclosporine, rats had increased embryo-fetal mortality compared with sirolimus alone. In rabbit embryo-fetal development studies, pregnant rabbits were administered sirolimus orally during the period of organogenesis (Gestational Day 6 to 18). […]
If too much is taken
Reports of overdose with sirolimus have been received; however, experience has been limited. In general, the adverse effects of overdose are consistent with those listed in the adverse reactions section [ see Adverse Reactions ( 6 ) ]. General supportive measures should be followed in all cases of overdose. Based on the low aqueous solubility and high erythrocyte and plasma protein binding of sirolimus, it is anticipated that sirolimus is not dialyzable to any significant extent. In mice and rats, the acute oral LD 50 was greater than 800 mg/kg.
Before you take anything new
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This page is built from the openFDA record of the U.S. Food and Drug Administration's approved labelling for this product, effective 30 June 2025. Label text has been shortened and reformatted for readability; safety wording has not been altered in meaning. FDA labelling describes products approved in the United States — brand names, strengths, formulations and approved uses may differ in your country. Always read the leaflet that comes with your own pack. PocketsInfo is not affiliated with, and is not endorsed by, the FDA. Retrieved 2026-07-30.