sirolimus at a glance
Medicine class
Selective immunosuppressant and mTOR inhibitor
Main licensed roles
Preventing kidney-transplant rejection in selected adults and treating sporadic lymphangioleiomyomatosis
Food
Take consistently either with food or without food
Important avoidance
Do not eat grapefruit or drink grapefruit juice
Monitoring
Regular blood levels and safety blood tests are needed
What is sirolimus used for?
The selected UK oral products are licensed for:
Preventing organ rejection in adults at low-to-moderate immunological risk who receive a kidney transplant, as part of specialist-managed immunosuppression.
Treating sporadic lymphangioleiomyomatosis when lung disease is moderate or lung function is declining.
Specialist non-licensed use for some complex vascular tumours and malformations, including in children.
How does sirolimus work?
Sirolimus binds to FKBP-12 and the resulting complex inhibits mTOR, a protein that controls cell growth and immune-cell activation. This suppresses T- and B-cell responses involved in transplant rejection and limits abnormal mTOR-driven cell proliferation in lymphangioleiomyomatosis.
sirolimus preparations and strengths
Oral solution
Route: Oral
Strengths: 1 mg/mL
Tablet
Route: Oral
Strengths: 0.5 mg, 1 mg, 2 mg
How to take sirolimus
Follow the specialist’s instructions and do not change treatment yourself.
Take it consistently in relation to food.
Swallow tablets whole; crushing, chewing or splitting is not recommended.
Measure the oral solution with the supplied syringe. Dilute it only in water or orange juice, stir well and drink immediately; rinse the container with more of the same liquid and drink that too.
Avoid grapefruit and grapefruit juice.
If ciclosporin is also prescribed, follow the specialist’s separation instructions.
sirolimus side effects
Common or expected effects
- Infections
- Diarrhoea, constipation, nausea or abdominal pain
- Headache or joint pain
- Mouth inflammation or ulcers
- Rash or acne
- Swelling and fluid retention
- High blood pressure
- Raised cholesterol, triglycerides or blood glucose
- Anaemia or reduced white cells or platelets
- Protein in the urine or increased creatinine
- Slower wound healing
Get urgent medical advice
- Severe allergy, including facial or throat swelling and breathing difficulty
- Serious infection or sepsis
- New cough or breathlessness from possible lung inflammation
- Blood clots, including pulmonary embolism
- Pancreatitis or severe liver injury
- Thrombotic microangiopathy, which may cause bruising, anaemia, kidney problems or neurological changes
- Lymphoma and other cancers, particularly skin cancer
sirolimus in pregnancy
Pregnancy information is limited. Product information advises avoiding sirolimus unless clearly necessary, while pregnancy specialists recognise that continued treatment may sometimes be safer than uncontrolled disease or transplant rejection. Discuss pregnancy planning or a positive pregnancy test promptly with the specialist, and do not stop sirolimus without advice.
sirolimus while breastfeeding
Product information recommends stopping breastfeeding during sirolimus treatment because adverse effects in the infant are possible. A small recent study detected low concentrations in breast milk but did not establish infant safety, so specialist assessment remains necessary.
sirolimus interactions
Sirolimus is affected by CYP3A4 and P-glycoprotein interactions. Check all new prescriptions, pharmacy medicines and supplements with the specialist or pharmacist.
Strong CYP3A4 inhibitors, including clarithromycin, itraconazole, ketoconazole and voriconazole
Can markedly increase sirolimus exposure and toxicity; co-administration is not recommended.
Strong CYP3A4 inducers, including rifampicin and rifabutin
Can markedly lower sirolimus exposure and reduce effectiveness; co-administration is not recommended.
Carbamazepine, phenytoin, phenobarbital and St John’s wort
May lower sirolimus levels and compromise disease or rejection control.
Common questions about sirolimus
Answers are fully visible for fast scanning and source review.
Why does sirolimus need blood-level monitoring?
Absorption and clearance vary between people, and many medicines can change its concentration. Results also differ between laboratory assay methods, so interpretation must use the local method and clinical findings.
Why must sirolimus be taken consistently with food?
Food changes how much sirolimus is absorbed. Taking it in the same way each time helps keep blood concentrations more stable.
Can I drink grapefruit juice while taking sirolimus?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.