Mifepristone (Korlym)
Korlym (mifepristone) is a cortisol receptor blocker used to control high blood sugar caused by Cushing's syndrome in adults who can't have or haven't benefited from surgery.
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 1 clinical label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
⚠️ FDA Boxed Warning — the FDA’s strongest safety alert ▾
Korlym will terminate a pregnancy. Because it blocks progesterone — a hormone essential for maintaining pregnancy — taking it while pregnant will cause pregnancy loss. This is the most critical safety concern with this medication.
Before starting Korlym, you must have a negative pregnancy test. While taking it, and for one month after stopping, you must use a reliable non-hormonal form of contraception (such as a copper IUD or barrier methods) unless you have had surgical sterilization. If treatment is paused for more than 14 days, another pregnancy test is required before restarting. Hormonal birth control (pills, patch, ring) does not work reliably with this medication and must not be used.
📖 Mifepristone (Korlym): Patient Information Guide
A plain-language walkthrough of Mifepristone (Korlym) — what it treats, how it works, how it’s taken, side effects, warnings and interactions. Tap any section to expand it.
🎯What it's used for▾
Korlym is approved for adults with endogenous Cushing's syndrome who have high blood sugar (type 2 diabetes or glucose intolerance) and cannot have surgery or haven't improved with it.
- Controls high blood sugar caused by excess cortisol in Cushing's syndrome
- Used when surgery has failed or isn't an option
- Not for treating ordinary type 2 diabetes unrelated to Cushing's syndrome
⚙️How it works▾
The body has special docking sites called glucocorticoid receptors that cortisol normally latches onto. In Cushing's syndrome, too much cortisol keeps activating these receptors, driving blood sugar dangerously high. Korlym blocks these receptors so cortisol can't connect to them — reducing its harmful effects on blood sugar. At lower doses, it also blocks progesterone receptors, which is why it can end a pregnancy and why strict contraception is required.
Because Korlym blocks the receptor rather than lowering cortisol itself, cortisol levels in the blood actually rise during treatment. This means standard cortisol blood tests cannot be used to judge whether you're getting the right amount of effect from the drug — your doctor will rely on symptoms and other markers instead.
💊How it's taken▾
Korlym is taken once daily by mouth, always with a meal — food significantly increases how much of the drug your body absorbs, so consistency matters. Swallow the tablet whole; do not split, crush, or chew it.
- Your prescriber will start at a lower dose and increase gradually, no more than once every 2–4 weeks
- Dose adjustments are based on how well your blood sugar improves and how well you tolerate the medication
- Lower maximum doses apply if you have kidney or liver problems, or if you take certain other medications
If you miss a dose, follow your prescriber's guidance — do not double up without being told to.
🤒Side effects — in detail▾
The most commonly reported side effects in clinical studies included:
- Nausea and vomiting
- Fatigue
- Headache
- Low potassium levels (can cause muscle weakness or cramps)
- Joint pain
- Swelling in the legs or feet
- Dizziness
- Decreased appetite
- High blood pressure
- Thickening of the uterine lining (in women)
More serious reactions — including signs of adrenal insufficiency (severe weakness, nausea, low blood pressure, low blood sugar) or significant vaginal bleeding — require stopping the medication and getting medical help right away.
⚠️Warnings & precautions▾
- Adrenal insufficiency: Korlym blocks cortisol's effects, so even though your cortisol blood level rises, your body may not be getting enough cortisol activity. Symptoms include profound weakness, severe nausea, extreme fatigue, low blood pressure, and low blood sugar. If this happens, stop Korlym immediately and seek emergency care. High doses of glucocorticoid medication may be needed to counteract the blockade.
- Low potassium (hypokalemia): Occurred in nearly half of patients in clinical studies. Potassium must be corrected before starting Korlym, and levels should be checked regularly during treatment.
- Vaginal bleeding and uterine changes: Women may experience unexpected vaginal bleeding or a thickening of the uterine lining. Extra caution is needed if you have a bleeding disorder or take blood thinners.
- Heart rhythm (QT prolongation): Korlym can lengthen the QT interval — an electrical measurement in the heart. Avoid combining it with other drugs that do the same, and tell your doctor about any heart rhythm conditions.
- Pregnancy termination: This is an absolute contraindication — see the boxed warning above.
🔀What it interacts with▾
Korlym affects the way many other drugs are broken down in the body, and several combinations are either forbidden or require dose adjustments.
- Simvastatin and lovastatin: Cannot be combined — Korlym dramatically increases their levels, raising the risk of serious muscle breakdown (rhabdomyolysis)
- Narrow-range drugs (cyclosporine, fentanyl, pimozide, quinidine, tacrolimus, sirolimus, ergotamine, dihydroergotamine): Contraindicated — Korlym raises their levels to potentially dangerous heights
- Strong CYP3A inhibitors (e.g., certain antifungals or antibiotics): Increase Korlym's own blood levels; use only when necessary with a dose cap
- CYP3A inducers (e.g., rifampin): Should not be used with Korlym — they reduce its effectiveness
- Hormonal contraceptives: Cannot be used with Korlym; switch to non-hormonal contraception
- Bupropion and efavirenz: Use cautiously — Korlym may alter their levels in the body
- Other CYP3A or CYP2C8/2C9 substrates: Use the lowest effective dose of those medications when combined with Korlym
This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.
📋Before taking it▾
- Pregnancy: Absolutely cannot take Korlym — it will cause pregnancy loss
- Women of reproductive potential: Must have a negative pregnancy test before starting; must use non-hormonal contraception throughout treatment and for one month after stopping
- History of unexplained vaginal bleeding, endometrial cancer, or atypical endometrial hyperplasia: Cannot take Korlym
- Taking systemic corticosteroids for a life-threatening reason (e.g., post-transplant immunosuppression): Cannot take Korlym — it would block those medications' effects
- Allergy to mifepristone or any ingredient in Korlym: Cannot take it
- Low potassium: Must be corrected before starting
- Kidney impairment: A lower maximum daily dose applies — discuss with your prescriber
- Liver impairment: A lower dose limit applies for mild-to-moderate liver disease; Korlym should not be used at all with severe hepatic impairment
🚑If you take too much▾
There is no documented clinical experience with Korlym overdose at this time. If you or someone else has taken more than prescribed, contact Poison Control (1-800-222-1222) or go to the nearest emergency room right away. Do not wait for symptoms to develop.
📡Pharmacodynamics — effects in the body▾
Korlym blocks the glucocorticoid receptor (the target that cortisol normally binds to), preventing cortisol from producing its usual effects on blood sugar and metabolism. Because the receptor is blocked rather than cortisol itself being reduced, the body's feedback system responds by producing even more cortisol — so blood cortisol levels rise during treatment, even as their harmful effects are suppressed. Mifepristone and its active breakdown products all bind to the glucocorticoid receptor more strongly than cortisol itself does, making the blockade highly effective.
🔬Pharmacokinetics — how your body processes it▾
Korlym is taken by mouth and reaches peak blood levels within 1–4 hours. It should always be taken with food, because food significantly increases absorption and helps keep levels consistent from day to day. The drug is heavily protein-bound in the bloodstream and reaches steady, stable levels in the body within about two weeks.
Korlym has a long half-life of roughly 85 hours, meaning it stays active in the body for several days after the last dose — an important consideration when adjusting other medications. It is broken down mainly by the liver (via the CYP3A4 enzyme) into three active metabolites, and about 90% of the drug is eliminated through the stool.
📦How to store it▾
Store at controlled room temperature, 25 °C (77 °F); excursions permitted to 15 to 30 °C (59 – 86 °F).
📄 Written from Mifepristone (Korlym)’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Every point is grounded in that labeling — nothing is invented. How we use AI →
Supplements & herbs that interact with Mifepristone (Korlym)
151 supplements and herbal products have documented interactions with Mifepristone (Korlym) in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.
- Major · 8
- Moderate · 104
- Minor · 39
Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.
🩺 Pharmacist Counseling Corner
Quick, plain-English answers to the questions patients ask most about Mifepristone (Korlym) — the kind of thing our pharmacy team would talk through with you at the counter.
Why am I taking this for Cushing's syndrome — isn't mifepristone the abortion pill? ▾
Why do I have to take it with food every time? ▾
What does adrenal insufficiency mean, and how will I know if it's happening to me? ▾
What kind of birth control can I use while I'm on Korlym? ▾
Are there medications I absolutely cannot take at the same time? ▾
My doctor mentioned my potassium needs monitoring. Why? ▾
Is Mifepristone (Korlym) available over the counter? ▾
💬 Answers drafted from Mifepristone (Korlym)’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Grounded in that labeling — nothing is made up. How we use AI →
🧰 Keep exploring
📈 How widely Mifepristone (Korlym) is used
A general measure of how commonly Mifepristone (Korlym) is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.
Think of this as a proxy for how widely Mifepristone (Korlym) is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.
How commonly is Mifepristone (Korlym) prescribed? Of the 1,596 medications we measure, Mifepristone (Korlym) ranks #1,150 by Medicaid prescriptions — more than 28% of them.
Utilization by Mifepristone (Korlym) product
Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.
mifepristone 300 MG Oral Tablet Most dispensed
Summed across the 3 of 4 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1245262
mifepristone 200 MG Oral Tablet
Summed across the 1 of 3 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 311704
Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.
Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Mifepristone (Korlym), and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 4 of 7 listed Mifepristone (Korlym) NDCs with Medicaid activity.
📈 What people report — real-world data (FDA FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Mifepristone (Korlym) — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Mifepristone (Korlym) in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
🏛️ The road to your pharmacy
How Mifepristone (Korlym) went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
🚨 Recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
Source: openFDA drug enforcement (recall) reports.
RxNorm Concept Web — From Ingredient to Every Form and Strength
This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.
RxCUI 6964 1 dose form · 2 strengths
-
Dose form (SCDF) Oral Tablet RxCUI 374644No current FDA listing
Look up RxCUI 6964 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
📦 Supply & shortage status
Whether Mifepristone (Korlym) is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
🏷️ Sold under these brand names
RxNorm drug class
Mifepristone (Korlym) belongs to the Progestin Antagonist class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
🔬 Where this comes from
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How we combine label and product data
HelloPharmacist combines public FDA and NLM records; we don’t author the underlying clinical facts. We identified 1 FDA-filed SPL label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. The representative label is the starting point for the displayed reference monograph; the 12 largest stored in-scope SPL records, which may include that representative, are compared section by section, and the longest available version of each section is retained. Forms, routes, brands, labelers, product-listed strengths, and product-record counts are aggregated separately from ingredient-matched FDA NDC Directory records; package records listed above are associated with the linked SPL; and the normalized concept hierarchy comes from NLM RxNorm.
For canonical ingredient pages, bounded product-attributed indication and administration excerpts may be added to the AI evidence, and the generator is instructed to preserve available product, brand, route, and form qualifiers instead of treating one label as universal. Where a section is identified as AI-written, its plain-language text is generated from bounded label evidence. New draft drug pages remain in the admin review queue before first publication. Corcept Therapeutics Incorporated is the representative DailyMed label linked for verification and dates; it is not the sole source used for the page.
This is general education, not medical advice — always consult your doctor or pharmacist about your medications and any medical condition. For the exact wording of the linked representative label, view that label on DailyMed; some displayed composite sections may come from other in-scope SPL labels. Learn how we use AI and our data sources & update cadence.