FOUNDAYO
Clinical safety rating
cautionComprehensive 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. |
| Molecular Weight | 452.6 |
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 | Avoid due to potential teratogenic effects; limited human data, animal studies show risk. |
| 2nd trimester | Avoid unless no safer alternative; risk of fetal harm. |
| 3rd trimester | Avoid in third trimester; may cause adverse fetal effects (e.g., oligohydramnios, neonatal toxicity). |
Clinical note
Comprehensive clinical and safety monograph for FOUNDAYO (FOUNDAYO).
| Placental transfer | Crosses placenta extensively; fetal concentrations reach maternal levels. |
| Breastfeeding | Excreted in breast milk in low amounts; use caution, monitor infant for adverse effects. |
| Lactation Rating | L3 (Moderately Safe) |
| 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 | 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. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
Hypersensitivity to active substance or excipientsSevere hepatic impairmentPregnancy (unless specific condition outweighs risk)
| 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. |
| Food/Dietary | No known food interactions. Maintain usual diet. |
| Clinical Pearls | FOUNDAYO is a monoclonal antibody targeting IL-23. Pre-treatment screening for latent tuberculosis is mandatory. Administer subcutaneously; rotate injection sites. Monitor for hypersensitivity reactions during infusion. Avoid live vaccines during treatment. |
| Patient Advice | Store in refrigerator, do not freeze. Protect from light. · Inject as prescribed; rotate sites (abdomen, thigh, upper arm). · Report signs of infection (fever, cough, skin redness) immediately. · Avoid live vaccines (e.g., MMR, varicella) during therapy. · Seek medical help for allergic reactions (hives, difficulty breathing). |
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