Osilodrostat
Osilodrostat is a cortisol synthesis inhibitor used to treat adults with Cushing's disease who cannot have pituitary surgery or for whom the surgery has not been fully effective. It works by blocking the 11beta-hydroxylase enzyme, which is responsible for the final step of cortisol production in the adrenal glands, thereby reducing excess cortisol levels in the body.
Osilodrostat treats excess cortisol in Cushing's disease by inhibiting the enzyme responsible for cortisol synthesis.
Key facts at a glance
- ATC
- H02CA02
- RxNorm
- 2286252
- Generic
- Osilodrostat
- Class
- atc-h02
- Brands
- Isturisa
- Availability
- rx
- Lactation
- unknown
- Routes
- oral
- Forms
- tablet
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Osilodrostat is indicated for the treatment of endogenous Cushing's syndrome, specifically Cushing's disease, in adult patients who are not candidates for or have not responded adequately to pituitary surgery.
Osilodrostat inhibits 11beta-hydroxylase (CYP11B1), the enzyme that catalyzes the final step of cortisol biosynthesis in the adrenal gland, converting 11-deoxycortisol to cortisol. By blocking this enzyme, it reduces cortisol production and helps normalize elevated cortisol levels.
Treatment requires regular monitoring of cortisol levels to avoid adrenal insufficiency. Common side effects may include fatigue, nausea, headache, and hypocortisolism. Patients should be advised about signs of adrenal insufficiency and the need for potential dose adjustments based on cortisol levels and clinical response.
Official drug label
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This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy