Overview
11 DESCRIPTION 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...
Mechanism of Action
12 CLINICAL PHARMACOLOGY 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.
Indications
- 1 INDICATIONS AND USAGE 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.
Common Doses
- 6 mg
- 2 mg
- 15 mg
- 5 mg
Dosage
2 DOSAGE AND ADMINISTRATION Sirolimus tablets are to be administered orally once daily, consistently with or without food [ see Dosage and Administration ( 2.5 ), Clinical Pharmacology ( 12.3 ) ]. Tablets should not be crushed, chewed or split. Patients unable to take the tablets should be prescribed the solution and instructed in its use. Renal Transplant Patients : Administer once daily by mouth, consistently with or without food ( 2 ). Administer the initial dose as soon as possible after transplantation and 4 hours after CsA ( 2.1 , 7.1 ).
Black Box Warning
WARNING: 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. Only physicians experienced in immunosuppressive therapy and management of renal transplant patients should use sirolimus for prophylaxis of organ rejection in patients receiving renal transplants.
Contraindications
- 4 CONTRAINDICATIONS Sirolimus is contraindicated in patients with a hypersensitivity to sirolimus [ see Warnings and Precautions ( 5.4 ) ]. Hypersensitivity to sirolimus ( 4 ).
Side Effects
- 6 ADVERSE REACTIONS 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.
Interactions
- 7 DRUG INTERACTIONS 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 ).