Isturisa 5mg Tablets
Overview
What is this medicine?
How to Use This Medicine
To use this medication correctly, follow your doctor's instructions and read all the information provided. You can take this medication with or without food.
Storing and Disposing of Your Medication
Keep your medication at room temperature in a dry location, avoiding storage in a bathroom. It's essential to store all medications in a safe place, out of the reach of children and pets, to prevent accidental ingestion.
Missing a Dose
If you miss a dose, skip it and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
Lifestyle & Tips
- Take Isturisa exactly as prescribed by your doctor, usually twice a day with food.
- Do not stop taking Isturisa suddenly without talking to your doctor, as this can lead to serious side effects (adrenal insufficiency).
- Attend all scheduled doctor appointments and laboratory tests (blood and urine tests, ECGs) to monitor your cortisol levels, electrolytes, and heart function.
- Be aware of symptoms of too little cortisol (adrenal insufficiency) and too much cortisol (if the medicine isn't working well), and report them to your doctor immediately.
- Carry a medical alert card or wear a medical alert bracelet indicating your condition and medication.
Available Forms & Alternatives
Available Strengths:
Dosing & Administration
Adult Dosing
Condition-Specific Dosing:
Pediatric Dosing
Dose Adjustments
Renal Impairment:
Hepatic Impairment:
Pharmacology
Mechanism of Action
Pharmacokinetics
Absorption:
Distribution:
Elimination:
Pharmacodynamics
Safety & Warnings
Side Effects
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of low potassium levels, including:
+ Muscle pain or weakness
+ Muscle cramps
+ Abnormal heartbeat
Signs of high blood pressure, such as:
+ Severe headache
+ Dizziness or fainting
+ Changes in eyesight
Signs of a urinary tract infection (UTI), including:
+ Blood in the urine
+ Burning or pain while urinating
+ Frequent or urgent need to urinate
+ Fever
+ Lower stomach pain or pelvic pain
Swelling
Hair growth
Pimples (acne)
Depression
This medication can cause very low cortisol levels, leading to potentially life-threatening adrenal gland problems. If you experience any of the following symptoms, contact your doctor immediately:
Severe stomach pain
Upset stomach or vomiting
Dizziness or fainting
Fast or abnormal heartbeat
Headache
Mood changes
Confusion
Muscle pain or weakness
Seizures
Shakiness
Sweating
Excessive sleepiness, tiredness, or weakness
Changes in appetite
Additionally, this medication can cause a type of abnormal heartbeat (prolonged QT interval). If you experience any of the following symptoms, contact your doctor right away:
Fast heartbeat
Abnormal heartbeat
Fainting
Other Possible Side Effects
Most people do not experience severe side effects, but some may occur. If you notice any of the following symptoms, contact your doctor or seek medical attention if they bother you or do not go away:
Feeling tired or weak
Diarrhea
Upset stomach or vomiting
Stomach pain or heartburn
Headache
Nose or throat irritation
Joint pain
Back pain
Cough
Flu-like symptoms
Trouble sleeping
Anxiety
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Symptoms of adrenal insufficiency (low cortisol): severe tiredness, weakness, nausea, vomiting, stomach pain, dizziness, fainting, low blood pressure, low blood sugar.
- Symptoms of low potassium (hypokalemia): muscle weakness, muscle cramps, heart palpitations, irregular heartbeat.
- Symptoms of heart rhythm problems (QT prolongation): feeling lightheaded, dizzy, fainting, fast or pounding heartbeat.
- Symptoms of worsening Cushing's (if dose is too low): weight gain, high blood pressure, high blood sugar, muscle weakness, easy bruising, moon face, buffalo hump.
Before Using This Medicine
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced.
Certain health conditions, including low potassium or magnesium levels.
If you are breastfeeding. Note that you should not breastfeed while taking this medication and for 1 week after your last dose.
This medication can interact with other drugs and health conditions. To ensure your safety, it is crucial to:
Inform your doctor and pharmacist about all the medications you are taking, including prescription and over-the-counter drugs, natural products, and vitamins.
Discuss all your health problems with your doctor and pharmacist.
Verify that it is safe to take this medication with your other medications and health conditions.
* Never start, stop, or change the dose of any medication without first consulting your doctor.
Precautions & Cautions
Regular blood tests will be necessary, as directed by your doctor. Be sure to discuss any concerns or questions you have with your doctor.
An electrocardiogram (ECG) will be required before starting this medication and at various points during treatment. Consult with your doctor to understand the schedule and implications.
Your doctor will also need to monitor your urine as part of your treatment regimen. Adhere to the urine testing schedule as advised by your doctor.
You may require supplemental potassium while taking this medication. Discuss your potassium levels and any necessary adjustments with your doctor.
If you are pregnant or planning to become pregnant, it is crucial to inform your doctor. You and your doctor will need to weigh the benefits and risks associated with using this medication during pregnancy to make an informed decision.
Overdose Information
Overdose Symptoms:
- Exaggerated signs of adrenal insufficiency (e.g., severe hypotension, profound fatigue, vomiting, abdominal pain, hypoglycemia)
- Severe hypokalemia
- Significant QT prolongation
What to Do:
Seek immediate medical attention. Call 911 or Poison Control at 1-800-222-1222. Management is supportive, including intravenous fluids, glucose, electrolyte correction (especially potassium), and potentially corticosteroids to manage adrenal insufficiency.
Drug Interactions
Major Interactions
- Strong CYP3A4 inducers (e.g., rifampin, carbamazepine, phenytoin, St. John's wort): May significantly decrease osilodrostat exposure, leading to loss of efficacy. Avoid co-administration or consider increasing osilodrostat dose with careful monitoring.
- Drugs that prolong QT interval (e.g., Class IA and Class III antiarrhythmics, some antipsychotics, macrolide antibiotics, fluoroquinolones): Osilodrostat can cause QT prolongation. Use with caution and monitor ECG.
Moderate Interactions
- Strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, clarithromycin, ritonavir): May increase osilodrostat exposure, increasing risk of adrenal insufficiency. Monitor for signs of adrenal insufficiency and consider osilodrostat dose reduction.
- Drugs that cause hypokalemia (e.g., loop diuretics, thiazide diuretics, laxatives): Osilodrostat can cause hypokalemia. Monitor potassium levels closely.
Monitoring
Baseline Monitoring
Rationale: To establish baseline cortisol levels and confirm diagnosis of Cushing's disease.
Timing: Prior to initiation of therapy.
Rationale: To establish baseline and guide initial dosing.
Timing: Prior to initiation of therapy.
Rationale: To establish baseline and monitor for hypokalemia, a common side effect.
Timing: Prior to initiation of therapy.
Rationale: To assess baseline QT interval and identify risk factors for QT prolongation.
Timing: Prior to initiation of therapy.
Rationale: To assess baseline hepatic function, especially important for dose adjustments in hepatic impairment.
Timing: Prior to initiation of therapy.
Routine Monitoring
Frequency: Weekly or bi-weekly during titration, then monthly or as clinically indicated once stable.
Target: Normalization of UFC levels.
Action Threshold: Persistent elevation indicates need for dose increase; significant reduction below normal range indicates need for dose decrease or temporary interruption.
Frequency: Weekly or bi-weekly during titration, then monthly or as clinically indicated once stable.
Target: Normalization of serum cortisol levels.
Action Threshold: Persistent elevation indicates need for dose increase; significant reduction below normal range indicates need for dose decrease or temporary interruption.
Frequency: Weekly or bi-weekly during titration, then monthly or as clinically indicated once stable.
Target: Normal range (3.5-5.0 mEq/L).
Action Threshold: Hypokalemia (<3.5 mEq/L) requires potassium supplementation and/or dose adjustment of osilodrostat.
Frequency: Periodically, especially if risk factors for QT prolongation are present or if symptoms arise.
Target: Normal QT interval.
Action Threshold: Significant QT prolongation (e.g., QTc >500 ms or increase >60 ms from baseline) requires dose reduction or interruption and electrolyte correction.
Frequency: Regularly, especially during titration.
Target: Individualized target.
Action Threshold: Hypotension may indicate adrenal insufficiency.
Frequency: Periodically, especially in diabetic patients.
Target: Individualized target.
Action Threshold: Hypoglycemia may indicate adrenal insufficiency.
Symptom Monitoring
- Signs and symptoms of adrenal insufficiency (e.g., severe fatigue, nausea, vomiting, abdominal pain, dizziness, hypotension, hypoglycemia)
- Signs and symptoms of hypokalemia (e.g., muscle weakness, cramps, palpitations, arrhythmias)
- Signs and symptoms of QT prolongation (e.g., palpitations, dizziness, syncope)
- Signs and symptoms of hyperandrogenism (e.g., hirsutism, acne, menstrual irregularities) in women, which may occur due to increased adrenal androgen precursors.
Special Patient Groups
Pregnancy
Osilodrostat is classified as Pregnancy Category D. Based on animal studies, it may cause fetal harm. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Women of childbearing potential should be advised to use effective contraception during treatment and for at least one week after the last dose.
Trimester-Specific Risks:
Lactation
Osilodrostat is likely excreted in human milk. Due to the potential for serious adverse reactions in the breastfed infant (e.g., adrenal insufficiency), breastfeeding is not recommended during treatment with Isturisa and for at least one week after the last dose.
Pediatric Use
Safety and effectiveness of Isturisa in pediatric patients have not been established. It is not indicated for use in children.
Geriatric Use
No overall differences in safety or effectiveness were observed between elderly patients (âĨ65 years) and younger patients. However, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
Clinical Information
Clinical Pearls
- Osilodrostat requires careful and frequent titration based on patient's cortisol levels and clinical response to avoid adrenal insufficiency.
- Patients must be educated on the signs and symptoms of adrenal insufficiency and hypokalemia, and instructed to seek immediate medical attention if they occur.
- Take Isturisa with food to improve absorption and reduce gastrointestinal side effects.
- Regular monitoring of serum potassium is crucial, as hypokalemia is a common and potentially serious side effect that may require supplementation.
- ECG monitoring is recommended at baseline and periodically, especially in patients with risk factors for QT prolongation or those on concomitant QT-prolonging medications.
Alternative Therapies
- Pituitary surgery (transsphenoidal adenomectomy) - primary treatment for Cushing's disease.
- Pasireotide (Signifor) - somatostatin analog, also for Cushing's disease.
- Mifepristone (Korlym) - glucocorticoid receptor blocker, for hyperglycemia in Cushing's syndrome.
- Ketoconazole - antifungal with cortisol-lowering effects (off-label for Cushing's).
- Cabergoline - dopamine agonist (off-label for Cushing's).
- Adrenalectomy (bilateral) - surgical option for severe cases or failed medical therapy.