[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Calcineurin inhibitors](https://durgical.com/en/pharmacology/classes/calcineurin-inhibitors/) › Ciclosporin

[Pharmacology](https://durgical.com/en/pharmacology/) · [Calcineurin inhibitors](https://durgical.com/en/pharmacology/classes/calcineurin-inhibitors/)

# Ciclosporin

A transplant medicine that keeps T cells from attacking the new organ. Its blood level is measured, and it can raise blood pressure and harm the kidneys.

Updated 2026-11-01

- Class: [Calcineurin inhibitors](https://durgical.com/en/pharmacology/classes/calcineurin-inhibitors/)
- Enzyme: Calcineurin, through cyclophilin A
- ATC code: L04AD01
- WHO Model List of Essential Medicines

Also called: cyclosporine, cyclosporin A

✂**Calcineurin, through cyclophilin A**Ciclosporin

ⓘ The figure shows the human complex of calcineurin, cyclophilin A and ciclosporin. Ciclosporin is a cyclic peptide, so in this entry it is a peptide chain rather than a small-molecule ligand.

**Target in 3D:** Calcineurin, through cyclophilin A. PDB structure 1MF8 (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/1MF8) · Drag to rotate · pinch to zoom

## Mechanism of action

Ciclosporin is a cyclic peptide of fungal origin. Inside T cells it binds cyclophilin, and the complex inhibits calcineurin. NFAT is not dephosphorylated and cannot reach the nucleus, so IL-2 and other cytokines are not produced and T-cell activation and proliferation are blocked.

- Binds cyclophilin inside the T cell
- The complex blocks the phosphatase calcineurin
- NFAT stays in the cytoplasm: no IL-2 is made
- T cells do not proliferate against the graft

## Pharmacokinetics

**Absorption**
Oral absorption is variable; different oral formulations are not bioequivalent

**Metabolism**
Extensively in the liver and gut by CYP3A4; also a P-glycoprotein substrate

**Elimination**
Mainly in the bile, as metabolites

**Half-life**
About 8 hours on average, ranging widely between patients

## Indications

- Prevention of rejection of kidney, liver and heart transplants
- Severe active rheumatoid arthritis that has not responded to methotrexate [Rheumatoid arthritis →](https://durgical.com/en/conditions/rheumatoid-arthritis/)
- Severe plaque psoriasis that has not responded to other systemic treatment
- Crohn disease, off label in some cases [Crohn disease →](https://durgical.com/en/conditions/crohn-disease/)

## Adverse effects

### Common

- Hypertension
- Tremor
- Hirsutism
- Gum hyperplasia
- Hyperkalaemia and low magnesium
- Raised lipids and uric acid

### Serious (rare, important)

- Nephrotoxicity, acute and chronic
- Serious infections
- Lymphoma and skin cancers
- Neurotoxicity, including seizures
- Liver toxicity

## Contraindications

- Hypersensitivity to ciclosporin or the formulation
- In rheumatoid arthritis or psoriasis: abnormal kidney function, uncontrolled hypertension or malignancy
- In psoriasis: concurrent PUVA or UVB therapy, methotrexate or other immunosuppressants

## Key interactions

**CYP3A4 inhibitors (azole antifungals, macrolides, diltiazem, verapamil) and grapefruit**
Raise ciclosporin levels and toxicity.

**CYP3A4 inducers (rifampicin, carbamazepine, phenytoin, St John's wort)**
Lower ciclosporin levels: risk of rejection.

**Statins**
Ciclosporin raises statin levels: myopathy and rhabdomyolysis.

**Potassium-sparing diuretics**
Hyperkalaemia; not used together.

**Other nephrotoxic drugs (aminoglycosides, NSAIDs)**
Additive kidney damage.

## What is monitored

- Ciclosporin trough blood levels
- Creatinine and urea
- Blood pressure
- Potassium, magnesium, uric acid and lipids
- Skin checks for cancer

## Administration and safety

- Oral capsules or solution and an intravenous form; different oral formulations are not bioequivalent and are not swapped without specialist supervision.
- The oral solution is diluted, preferably with orange or apple juice at room temperature, as the label describes.
- Taken on a consistent schedule, at the same times of day and in the same relation to meals.

## Nursing care

- Take blood for trough levels before the dose, as scheduled.
- Measure blood pressure at every visit.
- Check creatinine, potassium and magnesium results.
- Teach to avoid grapefruit and to report all new medicines and herbal products.
- Teach sun protection and the signs of infection; avoid live vaccines.

## Pregnancy and breastfeeding

Used in pregnancy after transplantation when needed; the treating team weighs the risk of rejection against the risks to the fetus.

## Memory aid

Ciclosporin is the transplant's guard with side effects in G: Gums grow, Gross hair (hirsutism), and the kidney Gets hurt.

## Test yourself

Think of the answer, then tap the question to see it.

## Which adverse effects help tell ciclosporin from tacrolimus?

Gum hyperplasia and hirsutism are typical of ciclosporin; tacrolimus causes more new-onset diabetes and neurotoxicity. Both are nephrotoxic.

## Why are trough levels of ciclosporin measured?

Its absorption and metabolism vary a lot, and both low levels (rejection) and high levels (nephrotoxicity) are dangerous.

## Why should a patient on ciclosporin avoid potassium-sparing diuretics?

Ciclosporin itself can cause hyperkalaemia; adding a potassium-sparing diuretic increases that risk.

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## Related drugs

- [Tacrolimus](https://durgical.com/en/pharmacology/tacrolimus/)
- [Sirolimus](https://durgical.com/en/pharmacology/sirolimus/)
- [Mycophenolate mofetil](https://durgical.com/en/pharmacology/mycophenolate-mofetil/)

## Related conditions

- [Rheumatoid arthritis](https://durgical.com/en/conditions/rheumatoid-arthritis/)
- [Crohn disease](https://durgical.com/en/conditions/crohn-disease/)

[← Back to the class: Calcineurin inhibitors](https://durgical.com/en/pharmacology/classes/calcineurin-inhibitors/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [Cyclosporine: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a601207.html) (MedlinePlus (U.S. National Library of Medicine), 2023); [DailyMed - CYCLOSPORINE solution](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f3dc2a50-1084-4190-a6f3-37034a04db86) (DailyMed (U.S. National Library of Medicine), 2025); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=L04AD01) (WHO Collaborating Centre for Drug Statistics Methodology, 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 39 (McGraw Hill, 2023).

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Representative model, for educational purposes only.

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