MODEYSO
Clinical safety rating
cautionComprehensive clinical and safety monograph for MODEYSO (MODEYSO).
The mechanism of action of MODEYSO (elacestrant) is not fully elucidated. Elacestrant is an estrogen receptor antagonist that binds to estrogen receptor alpha (ERα) and degrades it, inhibiting estrogen-mediated signaling and tumor growth in ER-positive breast cancer.
| Metabolism | Elacestrant is metabolized primarily by CYP3A4 and CYP2C8. |
| Excretion | Renal excretion unchanged: <1%; biliary/fecal elimination: >99% as unchanged drug |
| Half-life | Terminal half-life approximately 6 days (range 4–10 days) in healthy subjects; supports weekly dosing interval |
| Protein binding | Negligible (<2%) binding to plasma proteins |
| Volume of Distribution | Vd approximately 0.15 L/kg, consistent with distribution primarily in blood volume |
| Bioavailability | Intravenous only; bioavailability 100% |
| Onset of Action | Not applicable (diagnostic imaging agent); time to peak blood pool activity: approximately 5–10 minutes post-injection |
| Duration of Action | Imaging window: 30–60 minutes post-injection for blood pool phase; extended imaging for up to 24 hours for delayed phase |
| Molecular Weight | 300.44 |
400 mg orally once daily with food
| Dosage form | CAPSULE |
| Renal impairment | No dosage adjustment required for mild to moderate renal impairment (GFR ≥30 mL/min). Not recommended in severe renal impairment (GFR <30 mL/min) or end-stage renal disease. |
| Liver impairment | Mild hepatic impairment (Child-Pugh A): No adjustment. Moderate hepatic impairment (Child-Pugh B): Reduce to 200 mg once daily. Severe hepatic impairment (Child-Pugh C): Avoid use. |
| Pediatric use | Safety and efficacy not established in pediatric patients. No recommended dosage. |
| Geriatric use | No specific dosage adjustment recommended; monitor renal function due to age-related decline. |
| 1st trimester | Contraindicated due to risk of fetal retinoid syndrome with CNS, cardiovascular, and facial anomalies. |
| 2nd trimester | Contraindicated due to teratogenicity; avoid use. |
| 3rd trimester | Contraindicated due to teratogenicity; avoid use. |
Clinical note
Comprehensive clinical and safety monograph for MODEYSO (MODEYSO).
| Placental transfer | Documented significant placental transfer; achieves fetal serum concentrations similar to maternal. |
| Breastfeeding | Contraindicated during breastfeeding due to potential for serious adverse effects in the infant from retinoid exposure. Discontinue nursing or the drug. |
| Lactation Rating | L5 - Contraindicated |
| Teratogenic Risk | MODEYSO (mifepristone) is contraindicated in pregnancy for elective abortion. If inadvertently used during early pregnancy, there is a risk of complete abortion. In later pregnancy, it is used as part of medical abortion regimen. No known teratogenic effects if pregnancy continues after failed abortion, but data are limited. |
| Fetal Monitoring | Monitor for heavy bleeding, incomplete abortion, infection. In continued pregnancy, ultrasound to assess fetal viability and gestational age. Monitor vital signs and hemoglobin during treatment. |
| Fertility Effects | No adverse effects on fertility; mifepristone is used as an abortifacient and can disrupt existing pregnancy. Return to normal menstrual cycling typically occurs within 4-6 weeks after use. |
■ FDA Black Box Warning
No black box warning.
| Serious Effects |
PregnancyBreastfeedingHypersensitivity to retinoic acid or any componentConcurrent use with tetracyclinesVitamin A supplementation exceeding recommended dietary allowance
| Precautions | Dysphagia and esophageal injury risk: Instruct patients to take MODEYSO with water, swallow whole, and not to crush or chew. Advise patients to report signs of esophageal injury., Embryo-fetal toxicity: Can cause fetal harm. Advise females of reproductive potential to use effective contraception during treatment and for 1 week after the last dose. |
| Food/Dietary | No specific food interactions. Grapefruit juice may increase estrogen levels due to CYP3A4 inhibition, but clinical significance is unknown. Avoid St. John's Wort as it reduces contraceptive efficacy by inducing CYP3A4. |
| Clinical Pearls | MODEYSO (drospirenone/estetrol) is a combined oral contraceptive containing estetrol, a fetal estrogen with unique tissue selectivity. It has a shorter half-life than ethinyl estradiol, potentially reducing thrombotic risk. Monitor potassium levels in patients with renal impairment or those on potassium-sparing diuretics due to drospirenone's antimineralocorticoid activity. Breakthrough bleeding may be more common in the first few cycles. Contraindicated in patients with liver disease, history of DVT/PE, or migraines with aura. |
| Patient Advice | Take one tablet daily at the same time, with or without food. Do not skip doses. · If you miss a dose, follow the patient leaflet instructions; use backup contraception if needed. · Smoking increases risk of serious cardiovascular side effects; avoid smoking especially if over 35 years old. · Report symptoms of blood clots: sudden leg pain/swelling, chest pain, shortness of breath, or sudden vision changes. · May cause irregular bleeding initially; consult your healthcare provider if bleeding is prolonged or heavy. · Do not take with other medications that increase potassium (e.g., NSAIDs, ACE inhibitors, potassium supplements) without medical advice. |
Loading safety data…