Korlym
Generic name: mifepristone · Brand names: Korlym
Progestin Antagonist [epc]Information sourced from FDA Structured Product Labeling, updated September 25, 2025.
WARNING: TERMINATION OF PREGNANCY Mifepristone is a potent antagonist of progesterone and cortisol via the progesterone and glucocorticoid (GR-II) receptors, respectively. The antiprogestational effects will result in the termination of pregnancy. Pregnancy must therefore be excluded before the initiation of treatment with KORLYM and prevented during treatment and for one month after stopping treatment by the use of a non-hormonal medically acceptable method of contraception unless the patient has had a surgical sterilization, in which case no additional contraception is needed.
Pregnancy must also be excluded if treatment is interrupted for more than 14 days in females of reproductive potential. WARNING: TERMINATION OF PREGNANCY See full prescribing information for complete boxed warning. Mifepristone has potent antiprogestational effects and will result in the termination of pregnancy.
Pregnancy must therefore be excluded before the initiation of treatment with KORLYM, or if treatment is interrupted for more than 14 days in females of reproductive potential.
What is it used for?
1 INDICATIONS AND USAGE KORLYM (mifepristone) is a cortisol receptor blocker indicated to control hyperglycemia secondary to hypercortisolism in adult patients with endogenous Cushing's syndrome who have type 2 diabetes mellitus or glucose intolerance and have failed surgery or are not candidates for surgery. LIMITATIONS OF USE: KORLYM should not be used in the treatment of patients with type 2 diabetes unless it is secondary to Cushing's syndrome. KORLYM (mifepristone) is a cortisol receptor blocker indicated to control hyperglycemia secondary to hypercortisolism in adult patients with endogenous Cushing's syndrome who have type 2 diabetes mellitus or glucose intolerance and have failed surgery or are not candidates for surgery.
Important Limitations of Use: Do not use for the treatment of type 2 diabetes mellitus unrelated to endogenous Cushing's syndrome.
How to take it
Obtain a negative pregnancy test in females of reproductive potential prior to initiating treatment with KORLYM or if treatment is interrupted for more than 14 days. Administer once daily orally with a meal. The recommended starting dose is 300 mg once daily. Based on clinical response and tolerability, the dose may be increased in 300 mg increments to a maximum of 1200 mg once daily. Do not exceed 20 mg/kg per day. Renal impairment: do not exceed 600 mg once daily. Mild-to-moderate hepatic impairment: do not exceed 600 mg once daily. Do not use in severe hepatic impairment. Concomitant administration with strong CYP3A inhibitors: Do not exceed 900 mg once daily.
Testing Prior to and During
KORLYM Administration Obtain a negative pregnancy test in females of reproductive potential prior to initiating treatment with KORLYM or if treatment is interrupted for more than 14 days .
Adult Dosage The
recommended starting dose is 300 mg orally once daily. KORLYM must be given as a single daily dose. KORLYM should always be taken with a meal. Patients should swallow the tablet whole. Do not split, crush, or chew tablets. Dosing and titration The daily dose of KORLYM may be increased in 300 mg increments.
The dose of KORLYM may be increased to a maximum of 1200 mg once daily but should not exceed 20 mg/kg per day. Increases in dose should not occur more frequently than once every 2-4 weeks. Decisions about dose increases should be based on a clinical assessment of tolerability and degree of improvement in Cushing's syndrome manifestations.
Changes in glucose control, anti-diabetic medication requirements, insulin levels, and psychiatric symptoms may provide an early assessment of response (within 6 weeks) and may help guide early dose titration. Improvements in cushingoid appearance, acne, hirsutism, striae, and body weight occur over a longer period of time and, along with measures of glucose control, may be used to determine dose changes beyond the first 2 months of therapy. Careful and gradual titration of KORLYM accompanied by monitoring for recognized adverse reactions may reduce the risk of severe adverse reactions.
Dose reduction or even dose discontinuation may be needed in some clinical situations. If KORLYM treatment is interrupted, it should be reinitiated at the lowest dose (300 mg). If treatment was interrupted because of adverse reactions, the titration should aim for a dose lower than the one that resulted in treatment interruption.
Dosing in Renal Impairment No
change in initial dose of KORLYM is required in renal impairment. The maximum dose should be limited to 600 mg.
Dosing in Hepatic Impairment No
change in the initial dose of KORLYM is required in mild to moderate hepatic impairment. The maximum dose should be limited to 600 mg. KORLYM should not be used in severe hepatic impairment.
Concomitant Administration with CYP3A Inhibitors Ketoconazole
and other strong inhibitors of CYP3A, such as itraconazole, nefazodone, ritonavir, nelfinavir, indinavir, atazanavir, amprenavir and fosamprenavir, clarithromycin, conivaptan, lopinavir/ritonavir, posaconazole, saquinavir, telithromycin, or voriconazole may increase exposure to mifepristone. KORLYM should be used in combination with strong CYP3A inhibitors only when necessary. Administration of KORLYM to patients already being treated with strong CYP3A inhibitors: Start at a dose of 300 mg.
If clinically indicated, titrate to a maximum of 900 mg. Administration of strong CYP3A inhibitors to patients already being treated with KORLYM: Adjust the dose of KORLYM according to Table 1 . Table 1. Dose adjustment of KORLYM when strong CYP3A inhibitor is added Current dose of KORLYM Adjustment to dose of KORLYM if adding a strong CYP3A inhibitor 300 mg No change 600 mg Reduce dose to 300 mg.
If clinically indicated, titrate to a maximum of 600 mg 900 mg Reduce dose to 600 mg. If clinically indicated, titrate to a maximum of 900 mg 1200 mg Reduce dose to 900 mg
Warnings
Adrenal insufficiency : Patients should be closely monitored for signs and symptoms of adrenal insufficiency. Hypokalemia : Hypokalemia should be corrected prior to treatment and monitored for during treatment. Vaginal bleeding and endometrial changes : Women may experience endometrial thickening or unexpected vaginal bleeding. Use with caution if patient also has a hemorrhagic disorder or is on anti-coagulant therapy. QT interval prolongation : Avoid use with QT interval-prolonging drugs, or in patients with potassium channel variants resulting in a long QT interval. Use of Strong CYP3A Inhibitors: Concomitant use can increase mifepristone plasma levels. Use only when necessary and limit mifepristone dose to 900 mg.
Adrenal Insufficiency Patients
receiving mifepristone may experience adrenal insufficiency. Because serum cortisol levels remain elevated and may even increase during treatment with KORLYM, serum cortisol levels do not provide an accurate assessment of hypoadrenalism in patients receiving KORLYM. Patients should be closely monitored for signs and symptoms of adrenal insufficiency, including weakness, nausea, increased fatigue, hypotension, and hypoglycemia. If adrenal insufficiency is suspected, discontinue treatment with KORLYM immediately and administer glucocorticoids without delay.
High doses of supplemental glucocorticoids may be needed to overcome the glucocorticoid receptor blockade produced by mifepristone. Factors considered in deciding on the duration of glucocorticoid treatment should include the long half-life of mifepristone (85 hours). Treatment with KORLYM at a lower dose can be resumed after resolution of adrenal insufficiency.
Patients should also be evaluated for precipitating causes of hypoadrenalism (infection, trauma, etc.).
Hypokalemia In a
study of patients with Cushing's syndrome, hypokalemia was observed in 44% of subjects during treatment with KORLYM. Hypokalemia should be corrected prior to initiating KORLYM. During KORLYM administration, serum potassium should be measured 1 to 2 weeks after starting or increasing the dose of KORLYM and periodically thereafter. Hypokalemia can occur at any time during KORLYM treatment. Mifepristone-induced hypokalemia should be treated with intravenous or oral potassium supplementation based on event severity.
If hypokalemia persists in spite of potassium supplementation, consider adding mineralocorticoid antagonists.
Vaginal Bleeding and Endometrial Changes Being
an antagonist of the progesterone receptor, mifepristone promotes unopposed endometrial proliferation that may result in endometrium thickening, cystic dilatation of endometrial glands, and vaginal bleeding. KORLYM should be used with caution in women who have hemorrhagic disorders or are receiving concurrent anticoagulant therapy. Women who experience vaginal bleeding during KORLYM treatment should be referred to a gynecologist for further evaluation.
QT Interval Prolongation Mifepristone and
its metabolites block IKr. KORLYM prolongs the QTc interval in a dose-related manner. There is little or no experience with high exposure, concomitant dosing with other QT-prolonging drugs, or potassium channel variants resulting in a long QT interval. To minimize risk, the lowest effective dose should always be used.
Exacerbation/Deterioration of Conditions Treated with Corticosteroids Use
of KORLYM in patients who receive corticosteroids for other conditions (e.g., autoimmune disorders) may lead to exacerbation or deterioration of such conditions, as KORLYM antagonizes the desired effects of glucocorticoid in these clinical settings. For medical conditions in which chronic corticosteroid therapy is lifesaving (e.g., immunosuppression in organ transplantation), KORLYM is contraindicated.
Use of Strong CYP3A Inhibitors
KORLYM should be used with caution in patients taking ketoconazole and other strong inhibitors of CYP3A, such as itraconazole, nefazodone, ritonavir, nelfinavir, indinavir, atazanavir, amprenavir, fosamprenavir, clarithromycin, conivaptan, lopinavir/ritonavir, posaconazole, saquinavir, telithromycin, or voriconazole, as these could increase the concentration of mifepristone in the blood. The benefit of concomitant use of these agents should be carefully weighed against the potential risks. KORLYM should be used in combination with strong CYP3A inhibitors only when necessary, and in such cases the dose should be limited to 900 mg per day.
Pneumocystis
jiroveci Infection Patients with endogenous Cushing's syndrome are at risk for opportunistic infections such as Pneumocystis jiroveci pneumonia during KORLYM treatment. Patients may present with respiratory distress shortly after initiation of KORLYM. Appropriate diagnostic tests should be undertaken and treatment for Pneumocystis jiroveci should be considered.
Potential Effects of Hypercortisolemia
KORLYM does not reduce serum cortisol levels. Elevated cortisol levels may activate mineralocorticoid receptors which are also expressed in cardiac tissues. Caution should be used in patients with underlying heart conditions including heart failure and coronary vascular disease.
Who should not take it
4 CONTRAINDICATIONS KORLYM is contraindicated in: Pregnancy Patients taking drugs metabolized by CYP3A such as simvastatin, lovastatin, and CYP3A substrates with narrow therapeutic ranges, such as cyclosporine, dihydroergotamine, ergotamine, fentanyl, pimozide, quinidine, sirolimus, and tacrolimus, due to an increased risk of adverse events. Patients receiving systemic corticosteroids for lifesaving purposes (e.g., immunosuppression after organ transplantation) because KORLYM antagonizes the effect of glucocorticoids. Women with a history of unexplained vaginal bleeding or with endometrial hyperplasia with atypia or endometrial carcinoma.
Patients with known hypersensitivity to mifepristone or to any of the product components. Pregnancy ( 4 , 8.1 ) Patients taking drugs metabolized by CYP3A such as simvastatin, lovastatin, and CYP3A substrates with narrow therapeutic ranges Patients receiving systemic corticosteroids for lifesaving purposes Women with a history of unexplained vaginal bleeding or endometrial hyperplasia with atypia or endometrial carcinoma Patients with known hypersensitivity to mifepristone or to any of the product components
Pregnancy
Pregnancy Risk Summary
KORLYM is contraindicated in pregnancy because the use of KORLYM results in pregnancy loss. There are no data that assess the risk of birth defects in women exposed to KORLYM during pregnancy. Available data limited to exposure following a single dose of mifepristone during pregnancy showed a higher rate of major birth defects compared to the general population comparator . Mifepristone administered to pregnant mice, rats, and rabbits during organogenesis caused pregnancy loss in all species at clinically relevant doses based on body surface area comparisons . The inhibition of both endogenous and exogenous progesterone by mifepristone at the progesterone receptor results in pregnancy loss.
If KORLYM is used during pregnancy or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to a fetus. The estimated risk of fetal loss is elevated in patients with active Cushing's syndrome (24-30%), and the risk of major birth defects is unknown. In the U.S. general population, the estimated background risks of major birth defects and miscarriage in clinically recognized pregnancies are 2-4% and 15-20%, respectively.
Data Human Data There are no data on long term exposure to mifepristone in pregnancy. Available data are limited to exposure to a single dose of mifepristone for pregnancy termination. In a prospective study in France of 46 pregnancies exposed to a single dose of mifepristone alone and 59 pregnancies exposed to a single dose of mifepristone and misoprostol, the overall major birth defect rate (4%) was greater than the general population background rate of 2 to 3% (2 birth defects in each group).
There was no pattern of birth defects identified. Animal Data Reproductive studies were performed in mice, rats and rabbits at doses of 0.25 to 4.0 mg/kg (less than human exposure at the maximum clinical dose, based on body surface area). Because of the anti-progestational activity of mifepristone, fetal losses were much higher than in control animals.
Skull deformities were detected in rabbit studies at less than human exposure, although mifepristone did not cause any adverse developmental effects in rats or mice during organogenesis. These deformities were most likely due to the mechanical effects of uterine contractions resulting from antagonism of the progesterone receptor.
Side effects
Most common adverse reactions in Cushing's syndrome (≥ 20%): nausea, fatigue, headache, decreased blood potassium, arthralgia, vomiting, peripheral edema, hypertension, dizziness, decreased appetite, endometrial hypertrophy. To report suspected adverse reactions, contact Corcept Therapeutics at 1-855-844-3270 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.
Clinical Trials Experience Because
clinical trials are conducted under widely varying conditions, the adverse reaction rates observed cannot be directly compared to rates in other clinical trials and may not reflect the rates observed in clinical practice. Safety data on the use of KORLYM are available from 50 patients with Cushing's syndrome enrolled in an uncontrolled, open-label, multi-center trial (Study 400). Forty-three patients had Cushing's disease and all except one had previously undergone pituitary surgery.
Four patients had ectopic ACTH secretion, and three had adrenal carcinoma. Patients were treated for up to 24 weeks. A dose of 300 mg per day was administered for the initial 14 days; thereafter, the dose could be escalated in increments of 300 mg per day based on assessments of tolerability and clinical response.
Doses were escalated up to 900 mg per day for patients <60 kg, or 1200 mg per day for patients >60 kg. The most frequently reported adverse reactions (reported in ≥20% of patients, regardless of relationship to KORLYM) were nausea, fatigue, headache, decreased blood potassium, arthralgia, vomiting, peripheral edema, hypertension, dizziness, decreased appetite, and endometrial hypertrophy. Drug-related adverse events resulted in dose interruption or reduction in study drug in 40% of patients.
The adverse reactions that occurred in ≥10% of the Cushing's syndrome patients receiving KORLYM, regardless of relationship to KORLYM, are shown in Table 2 . Table 2. Treatment Emergent Adverse Events Occurring in ≥10% of Cushing's Syndrome Patients Receiving KORLYM Body System/Adverse Reaction Percent (%) of Patients Reporting Event (n = 50) *The denominator was 26 females who had baseline and end-of-trial transvaginal ultrasound Gastrointestinal disorders Nausea 48 Vomiting 26 Dry mouth 18 Diarrhea 12 Constipation 10 General disorders and administration/site conditions Fatigue 48 Edema peripheral 26 Pain 14 Nervous system disorders Headache 44 Dizziness 22 Somnolence 10 Musculoskeletal and connective tissue disorders Arthralgia 30 Back pain 16 Myalgia 14 Pain in extremity 12 Investigations Blood potassium decreased 34 Thyroid function test abnormal 18 Infections and infestations Sinusitis 14 Nasopharyngitis 12 Metabolism and nutrition disorders Decreased appetite 20 Anorexia 10 Vascular disorders Hypertension 24 Reproductive system and breast disorders Endometrial hypertrophy 38* Respiratory, thoracic, and mediastinal disorders Dyspnea 16 Psychiatric disorders Anxiety 10 Laboratory Tests Reductions in high density lipoprotein-cholesterol (HDL-C) levels have been observed following treatment with KORLYM. In study subjects that experienced declines in HDL-C, levels returned to baseline following discontinuation of drug. The clinical significance of the treatment-related reduction in HDL-C levels in patients with Cushing's syndrome is not known.
In a study of patients with Cushing's syndrome, hypokalemia was observed in 44% of subjects during treatment with KORLYM. In these cases, hypokalemia responded to treatment with potassium supplementation and/or mineralocorticoid antagonist therapy (e.g., spironolactone or eplerenone). Hypokalemia should be corrected prior to initiating KORLYM. Elevations of thyroid-stimulating hormone (TSH) were seen in subjects treated with KORLYM. Of the 42 subjects with detectable TSH at baseline, eight (19%) had increases in TSH above the normal range, while remaining asymptomatic. The TSH levels returned to normal in most patients without intervention when KORLYM was discontinued at the end of the study.
Vaginal Bleeding and Endometrial Changes In Study 400, the thickness of the endometrium increased from a mean of 6.14 mm at baseline (n=23) to 15.7 mm at end-of-trial (n=18) in premenopausal women; in postmenopausal women the increase was from 2.75 mm (n=6) to 7.35 mm (n=8). Endometrial thickness above the upper limit of normal was reported in 10/26 females who had baseline and end-of-trial transvaginal ultrasound (38%). The endometrial thickness returned to the normal range in 3 out of 10 patients 6 weeks after treatment cessation at the end of the study.
Vaginal bleeding occurred in 5 out of 35 females (14%). Two of five subjects with vaginal bleeding had normal endometrial thickness. Endometrial biopsies were performed in six patients; five of these patients had endometrial thickening. No endometrial carcinoma was detected in the sampled cases.
Additional Data from Clinical Trials The following are adverse events that were reported in Study 400 at frequencies of ≥ 5% to 10%, and may be related to KORLYM's mechanism of action: Gastrointestinal disorders: gastroesophageal reflux, abdominal pain General disorders and administration site conditions: asthenia, malaise, edema, pitting edema, thirst Investigations: blood triglycerides increased Metabolism and nutrition disorders: hypoglycemia Musculoskeletal and connective tissue disorders: muscular weakness, flank pain, musculoskeletal chest pain Psychiatric disorders: insomnia Reproductive system and breast disorders: vaginal hemorrhage, metrorrhagia Adrenal Insufficiency Adrenal insufficiency was reported in two subjects (4%) in Study 400. The most typical symptoms of adrenal insufficiency were nausea and decreased appetite. No hypotension or hypoglycemia was reported during the events.
Adrenal insufficiency resolved in both cases with KORLYM interruption and /or dexamethasone administration. Rash Generalized, maculo-papular rash was reported in 2 subjects (4%) in Study 400. Two additional subjects developed pruritus (4%). None resulted in discontinuation of KORLYM, and all the events resolved by the end of the study.
Postmarketing Experience The
following adverse reaction has been identified during post approval use of KORLYM. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. - Angioedema
All information on this site is provided “as-is” for informational purposes only and is not a substitute for medical advice or treatment. You should consult with a medical professional if you have any questions about your health. Source: FDA Structured Product Labeling.