Isturisa

Isturisa is the brand name for osilodrostat, a prescription medication approved for adults with Cushing's disease. It is a targeted therapy that inhibits 11β-hydroxylase (CYP11B1) in the adrenal cortex, reducing production of cortisol and helping to control hypercortisolism in patients for whom pituitary surgery has not achieved remission or is not feasible.

Administration and dosing are oral. The dose is individualized and titrated based on clinical response and laboratory measures, such as morning serum cortisol or 24-hour urinary free cortisol, with the goal of normalizing cortisol levels while limiting side effects. Dosing is continued as long as benefit outweighs risk and may require adjustment over time.

Common adverse effects include fatigue, nausea, headaches, edema, and dizziness. Electrolyte disturbances, especially hypokalemia, and hypertension can occur, reflecting broader effects on mineralocorticoid pathways. There is a potential risk of adrenal insufficiency if cortisol becomes too low. Rare but serious events may include liver function abnormalities. Patients require regular monitoring of electrolytes, blood pressure, weight, and cortisol markers, and should report symptoms such as weakness, confusion, or swelling promptly.

Interactions are important: osilodrostat is metabolized by CYP3A4, and concomitant use with strong CYP3A inhibitors or inducers can alter drug exposure, necessitating dose adjustments or avoidance of certain drugs.

Isturisa was approved by regulatory agencies in the early 2020s for adults with Cushing's disease and is used as systemic therapy when surgical options are insufficient or not curative.