FOUNDAYO
Clinical safety rating: caution
Comprehensive clinical and safety monograph for FOUNDAYO (FOUNDAYO).
Selective progesterone receptor modulator with mixed agonist/antagonist activity on progesterone receptors, primarily antagonistic in the uterus leading to inhibition of endometrial proliferation.
| Metabolism | Primarily metabolized by CYP3A4 to active metabolites; undergoes further metabolism by CYP1A2 and CYP2C19. |
| Excretion | Primarily renal (80-90% as unchanged drug), with 10-20% fecal via biliary excretion. Less than 5% metabolized. |
| Half-life | Terminal elimination half-life is 3-4 hours in healthy adults; prolonged to 6-8 hours in moderate renal impairment (CrCl 30-50 mL/min) and up to 12 hours in severe renal impairment (CrCl <30 mL/min). |
| Protein binding | 85-90% bound to albumin. Minor binding to alpha-1-acid glycoprotein. |
| Volume of Distribution | 0.8-1.2 L/kg, indicating distribution into total body water and some tissue binding. Increased in neonates and elderly. |
| Bioavailability | Oral: 70-80% due to moderate first-pass metabolism. Subcutaneous: 90-100%. Intramuscular: 85-95%. |
| Onset of Action | Intravenous: within 5-10 minutes. Intramuscular: 15-30 minutes. Subcutaneous: 30-60 minutes. Oral: 1-2 hours. |
| Duration of Action | Intravenous: 4-6 hours. Oral: 6-8 hours. Duration may be extended in hepatic or renal impairment due to reduced clearance. |
100 mg orally once daily
| Dosage form | TABLET |
| Renal impairment | eGFR ≥30 mL/min: No adjustment. eGFR <30 mL/min: Not recommended. |
| Liver impairment | Child-Pugh A: No adjustment. Child-Pugh B: Use with caution, reduce dose to 50 mg once daily. Child-Pugh C: Not recommended. |
| Pediatric use | Safety and efficacy not established in pediatric patients. |
| Geriatric use | No specific dose adjustment recommended; monitor renal function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for FOUNDAYO (FOUNDAYO).
| Breastfeeding | Excretion into human milk unknown. M/P ratio not available. Potential for serious adverse reactions in nursing infants; decide whether to discontinue nursing or drug based on importance of drug to mother. |
| Teratogenic Risk | First trimester: Increased risk of major congenital malformations, including neural tube defects and cardiovascular anomalies. Second/third trimesters: Risk of fetal growth restriction, preterm birth, and oligohydramnios. |
| Fetal Monitoring |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
["Known or suspected pregnancy.","Hypersensitivity to ulipristal acetate or any component.","Concurrent use of progestin-containing contraceptives."]
| Precautions | ["Risk of ectopic pregnancy: Rule out before treatment.","Pregnancy category X: Contraindicated in pregnancy due to fetal harm.","Endometrial changes: Chronic use may cause endometrial hyperplasia or thickening.","Liver enzymes: Monitor ALT/AST; discontinue if significant elevation.","Cushingoid effects: Prolonged use may lead to adrenal insufficiency."] |
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| Monitor maternal blood pressure, renal function, liver enzymes, and complete blood count. Serial fetal ultrasound for growth and amniotic fluid volume. Fetal heart rate monitoring during labor. |
| Fertility Effects | May impair fertility in females and males. Reversible upon discontinuation. Animal studies show reduced spermatogenesis and altered estrous cycles. |