osilodrostat
Isturisa (osilodrostat) is an oral cortisol synthesis inhibitor from Recordati Rare Diseases for adults with endogenous Cushing's syndrome when surgery is not an option or has not been curative. It blocks the enzyme that makes cortisol in the adrenal glands, lowering the excess hormone that drives the disease.
This page is based on FDA prescribing information and the EMA medicine record for osilodrostat, cross-checked with DailyMed, MedlinePlus, and the National Cancer Institute dictionary; the mechanism is explained in plain language, and analogies are used only where they stay accurate.
How it works
Explains what the medicine does in the body, not dosing, side effects, or safety.
An analogy
In Cushing's syndrome the adrenal glands run a hormone factory at full tilt, churning out cortisol around the clock. Osilodrostat removes the machine from the final workstation of that assembly line. Without it, the factory cannot finish the cortisol product, and the hormone level in the blood falls back toward normal.
In simple terms
Cushing's syndrome is caused by the body producing too much cortisol, a hormone made by the adrenal glands. Osilodrostat is taken by mouth and blocks the enzyme that performs the last step of cortisol production, so the glands make less of the hormone. By lowering cortisol toward normal levels, it addresses the source of the disease's symptoms in adults who cannot be treated with surgery or whose surgery has not cured them.
In depth
Osilodrostat is an orally bioavailable inhibitor of both steroid 11-beta-hydroxylase (cytochrome P450 CYP11B1) and aldosterone synthase (CYP11B2, steroid 18-hydroxylase). By binding and inhibiting CYP11B1, the enzyme that catalyses the final step of cortisol synthesis from the precursor 11-deoxycortisol, it prevents the production of excess cortisol and normalizes cortisol levels. Inhibition of CYP11B2 also affects aldosterone synthesis from corticosterone and 11-deoxycorticosterone in the adrenal gland. Cushing disease is most often caused by an adrenocorticotropic hormone-secreting pituitary tumor, and osilodrostat acts downstream of that signal at the adrenal level.
See it in motion
A schematic animation of the mechanism — simplified for clarity, not drawn to scale.
Osilodrostat is taken by mouth and blocks the enzyme that performs the last step of cortisol production, so the glands make less of the hormone.
- In Cushing's syndrome the adrenal glands run a hormone factory at full tilt, churning out cortisol around the clock.
- Osilodrostat removes the machine from the final workstation of that assembly line.
- Without it, the factory cannot finish the cortisol product, and the hormone level in the blood falls back toward normal.
- By lowering cortisol toward normal levels, it addresses the source of the disease's symptoms in adults who cannot be treated with surgery or whose surgery has not cured them.
Target: Steroid 11-beta-hydroxylase (CYP11B1)
The adrenal enzyme that catalyses the final step of cortisol synthesis from 11-deoxycortisol; blocking it stops the adrenal glands from overproducing cortisol.
Approved uses
Approved uses differ by country and change over time. Always follow your local prescribing information.
Approved uses in United States
FDA- For the treatment of endogenous hypercortisolemia in adults with Cushing's syndrome for whom surgery is not an option or has not been curative
Approved uses in European Union
EMA- For the treatment of endogenous Cushing's syndrome in adults
Official sources
The statements on this page trace back to these records.
- Isturisa (osilodrostat) — Summary of product characteristics and package leaflet, English version
European Medicines Agency
- DailyMed: ISTURISA (osilodrostat) official US label
U.S. National Library of Medicine, DailyMed
- U.S. Food and Drug Administration: osilodrostat prescribing information
U.S. Food and Drug Administration
- MedlinePlus: osilodrostat
MedlinePlus, U.S. National Library of Medicine
- National Cancer Institute: osilodrostat
National Cancer Institute
This page explains how the medicine works — it isn’t the patient leaflet. For anything that applies to you, read the leaflet that came with your medicine or ask your pharmacist.
MedUnfold provides educational content and is not medical advice. Always follow your local prescribing information and healthcare professional.