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SIROLIMUS — 0.5 mg / 1 mg / 2 mg / 3 mg / 5 mg tablets

mTOR inhibitor • immunosuppressant • renal transplant • LAM • Rx-only
Prescription-only medicine. Educational content: strengths, brand examples, safety notes, FAQ, and official references. Always follow your local leaflet and clinician guidance.

⚠️
BOXED WARNING: Immunosuppression • not for liver/lung transplant
Increased risk of infection and lymphoma. Being studied for longevity (off-label) at low intermittent doses — NOT FDA approved for anti-aging.
✅ Rx-only
✅ mTOR inhibitor
✅ TDM required

🔎 Quick Links
📦 Snapshot
🧠 Overview
🏷️ Brands
⚠️ Safety
❓ FAQ
📚 References

📦 Product Snapshot

Active substanceSirolimus (formerly rapamycin)
Available strengths0.5 mg · 1 mg · 2 mg · 3 mg · 5 mg
Dosage formFilm‑coated tablets · oral solution available
Strengths vary by manufacturer. Tablets are not interchangeable with solution without dose adjustment. Therapeutic drug monitoring (TDM) is mandatory.
Reference brandRapamune® (Pfizer)
India brand examplesRapacan® (1 mg, 2 mg) · Siroboon® (1 mg, 2 mg, 3 mg, 5 mg)
Primary indicationsProphylaxis of renal transplant rejection · Lymphangioleiomyomatosis (LAM)
Label‑first: Used in combination with cyclosporine and corticosteroids, or as part of calcineurin inhibitor‑free regimens in specific populations.

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Rx-only • label-first • verify local guidance

🧠 Overview

Sirolimus, also known as rapamycin, is an mTOR kinase inhibitor. Unlike calcineurin inhibitors (tacrolimus, cyclosporine) that block T‑cell activation at an early stage, sirolimus inhibits the response of T‑cells to cytokines (IL‑2, IL‑4, IL‑15), blocking cell cycle progression from G1 to S phase. This unique mechanism allows for synergistic immunosuppression when combined with cyclosporine, while also offering calcineurin inhibitor‑sparing regimens to preserve renal function.

In nephrology, sirolimus is used for prophylaxis of acute rejection in kidney transplant recipients. It is particularly valuable in patients who develop nephrotoxicity from calcineurin inhibitors or those with evidence of CNI‑induced renal damage on biopsy [citation:6]. Beyond transplantation, sirolimus is approved for lymphangioleiomyomatosis (LAM), a rare cystic lung disease affecting women of childbearing age.

Emerging research in longevity: Over the past decade, rapamycin has been shown to extend lifespan in multiple model organisms (yeast, worms, flies, mice) by inhibiting mTORC1, a key pathway linking nutrient sensing to aging [citation:3]. This has generated immense interest in repurposing sirolimus as a geroprotector — an agent that targets the biology of aging itself.

Critical distinction: Longevity use is off-label and investigational. It employs low intermittent dosing (e.g., 5‑15 mg once weekly) rather than the daily low‑dose (0.5‑2 mg) or high‑dose protocols used in transplantation [citation:1][citation:2]. Multiple NIH‑funded trials (NCT05949658, NCT06727305, NCT06658093) are actively investigating optimal dosing, safety, and biomarkers of aging in healthy older adults [citation:1][citation:2][citation:8]. Sirolimus is not FDA‑approved for anti‑aging, and self‑administration carries significant risks.

🏷️ Strengths & Brand Examples

Verified strengths (by brand)
Rapacan® (Biocon)
  • Sirolimus 1 mg film‑coated tablets
  • Sirolimus 2 mg film‑coated tablets
Siroboon® (Kachhela Medex)
  • Sirolimus 1 mg tablets
  • Sirolimus 2 mg tablets
  • Sirolimus 3 mg tablets
  • Sirolimus 5 mg tablets
Other India brands (examples)
  • Siromus® (1 mg, 2 mg — Panacea Biotec)
  • Rapimmune® (1 mg — Zydus Cadila)
Important note on formulations
Sirolimus is also available as an oral solution (1 mg/mL) for patients who cannot swallow tablets or require precise dosing adjustments. The 0.5 mg (500 mcg) tablet strength is available in some markets, particularly for paediatric dosing and low‑dose longevity protocols [citation:1].
Note: brand availability changes. Verify manufacturer and on‑pack labeling for current listings. Siroboon offers a broader range of strengths (1‑5 mg), while Rapacan focuses on 1/2 mg presentations.

⚠️ Safety, Side Effects & Monitoring

Commonly discussed effects
  • Peripheral edema, hypertension
  • Hypertriglyceridemia, hypercholesterolemia (dose‑dependent)
  • Mouth ulcers / stomatitis (very common) [citation:4]
  • Delayed wound healing, lymphocele formation
  • Thrombocytopenia, leukopenia, anemia
  • Proteinuria, decline in renal function (when used without CNI)
  • Interstitial lung disease / non‑infectious pneumonitis (rare, serious)
At low intermittent doses (longevity protocols), side effects are often milder — transient mouth ulcers, mild GI discomfort, temporary lipid changes.
Label-first warnings (boxed & serious)
• Immunosuppression: Increased susceptibility to infection and possible lymphoma.
• Liver transplantation: Excess mortality, graft loss, hepatic artery thrombosis — do not use.
• Lung transplantation: Bronchial anastomotic dehiscence — do not use.
• Hypersensitivity/angioedema: especially when co‑administered with ACE inhibitors.
• Embryo‑fetal toxicity: Can cause fetal harm. Effective contraception required during and for 12 weeks after therapy.
• Male infertility: Azoospermia or oligospermia reported; reversible in most cases.
• Live vaccines: Avoid during treatment.
• Drug interactions: Strong CYP3A4/P‑gp inhibitors (ketoconazole, clarithromycin) increase levels; inducers (rifampin) decrease levels.
Therapeutic Drug Monitoring (TDM)

Sirolimus requires routine blood level monitoring due to narrow therapeutic index and inter‑patient variability. Target trough concentrations depend on indication and combination therapy:

  • De novo renal transplant (with cyclosporine): 5‑15 ng/mL
  • Maintenance renal transplant (CNI‑free): 12‑20 ng/mL (first year), then 8‑15 ng/mL
  • LAM (lymphangioleiomyomatosis): 5‑15 ng/mL
  • Longevity protocols (investigational): targeting 5‑7 ng/mL trough [citation:1][citation:7] or using intermittent weekly dosing without continuous trough monitoring [citation:2]

Levels >15 ng/mL are associated with increased frequency of adverse effects (thrombocytopenia, hyperlipidemia, stomatitis).

❓ FAQ

FAQ question #1: Is sirolimus the same as rapamycin?
Answer: Yes, sirolimus and rapamycin refer to the same compound. Rapamycin was the original name given after its discovery in soil bacteria from Rapa Nui (Easter Island). Sirolimus is the United States Adopted Name (USAN) used in FDA‑approved labeling.
FAQ question #2: Why can’t sirolimus be used in liver or lung transplant patients?
Answer: Clinical trials showed an increased risk of hepatic artery thrombosis (leading to graft loss or death) in liver recipients, and bronchial anastomotic dehiscence in lung recipients. These complications are believed to be related to sirolimus’s anti‑proliferative effects on vascular and airway healing. Use in these populations is contraindicated.
FAQ question #3: I’ve heard sirolimus is used for anti-aging / longevity. Is this true?
Answer: Yes, sirolimus (rapamycin) is the most studied compound in geroscience. It extends lifespan in animals by inhibiting the mTOR pathway. Multiple human trials are now underway in healthy older adults (e.g., RAP PAC, RESTOR, MTOR in Older Adults) to test safety and efficacy for delaying aging. However, this use is strictly investigational and off-label. It is NOT FDA‑approved for anti-aging, and should only be used under medical supervision with appropriate monitoring. Self‑administration carries serious risks including immunosuppression, mouth ulcers, and metabolic changes.
FAQ question #4: How is longevity dosing different from transplant dosing?
Answer: Transplant patients typically take sirolimus daily (1‑5 mg/day) to maintain continuous immunosuppression with trough levels 5‑15 ng/mL. Longevity protocols use low intermittent dosing — e.g., 5‑15 mg once weekly — aiming for gentle mTOR modulation without sustained immune suppression. Some trials also use very low daily doses (0.5 mg) targeting 5‑7 ng/mL trough. These approaches are experimental and still being optimized.
FAQ question #5: What is the difference between Rapacan and Siroboon brands in India?
Answer: Rapacan (1 mg, 2 mg) is manufactured by Biocon, a large Indian biotechnology company with established pharmaceutical manufacturing standards. Siroboon (available in 1 mg, 2 mg, 3 mg, and 5 mg) is manufactured by Kachhela Medex. Patients and clinicians should verify product quality through routine therapeutic drug monitoring, as sirolimus absorption can vary between formulations. Always use products from licensed, verified sources and monitor blood levels as mandated by transplant or research protocols.

⚠️ Medical disclaimer
Educational content only. This does not replace medical advice, diagnosis, or treatment. Prescription-only medicines should be used under clinician supervision and according to local approved labeling. Transplant immunosuppression requires specialist oversight and therapeutic drug monitoring. Longevity use of sirolimus is investigational and not FDA‑approved.