GENCEPT 10/11-21
Clinical safety rating
cautionComprehensive clinical and safety monograph for GENCEPT 10/11-21 (GENCEPT 10/11-21).
GENCEPT 10/11-21 is a combination contraceptive vaginal ring containing ethinyl estradiol and etonogestrel. Ethinyl estradiol is an estrogen that suppresses gonadotropin release, inhibiting ovulation. Etonogestrel is a progestin that thickens cervical mucus, inhibiting sperm penetration, and alters the endometrium.
| Metabolism | Ethinyl estradiol is primarily metabolized by CYP3A4 via hydroxylation; etonogestrel is metabolized by CYP3A4 and CYP2C9. |
| Excretion | Renal (30-40% as unchanged drug and metabolites), biliary/fecal (50-60% as metabolites) |
| Half-life | Terminal elimination half-life is 24-30 hours; allows once-daily dosing; steady-state achieved in 5-7 days |
| Protein binding | Ethinyl estradiol: 97-98% bound to albumin; desogestrel: 91-96% bound to SHBG and albumin |
| Volume of Distribution | Ethinyl estradiol: 2.7-3.9 L/kg; desogestrel: 1.5-2.0 L/kg; indicates extensive tissue distribution |
| Bioavailability | Oral: ethinyl estradiol ~45% (first-pass metabolism), desogestrel ~76% (as active metabolite etonogestrel) |
| Onset of Action | Oral: 3-5 days for therapeutic effect (contraception) |
| Duration of Action | Oral: 24 hours (contraceptive coverage); requires daily dosing; missed pills reduce efficacy |
| Molecular Weight | 252.31 |
One tablet (10 mg ethinyl estradiol and 11 mg gestodene on days 1-7, then placebo on days 8-21) orally once daily for 21 days, followed by 7 placebo days.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment. Contraindicated in severe renal disease or acute renal failure. |
| Liver impairment | Contraindicated in severe hepatic disease, hepatocellular carcinoma, or active liver disease. Use with caution in mild to moderate impairment; no specific dose recommendations available. |
| Pediatric use | Not indicated for use before menarche. Post-menarche, same dosing as adults: one tablet daily on days 1-21, then 7 placebo days. |
| Geriatric use | Not indicated for use after menopause. No specific dose adjustments in elderly due to lack of use. |
| 1st trimester | Contraindicated due to the risk of fetal malformations including cleft lip/palate, cardiac defects, and neural tube defects. |
| 2nd trimester | Avoid use; second trimester exposure may cause fetal growth retardation and neurodevelopmental effects. |
| 3rd trimester | Contraindicated; third trimester use is associated with neonatal withdrawal syndrome, respiratory depression, and feeding difficulties. |
Clinical note
Comprehensive clinical and safety monograph for GENCEPT 10/11-21 (GENCEPT 10/11-21).
| Placental transfer | Readily crosses the placenta; fetal plasma concentrations can approach maternal levels. Animal studies show high transfer rates; human data limited but confirm transfer. |
| Breastfeeding | Excreted into breast milk in low concentrations; however, due to potential for serious adverse reactions in nursing infants, including sedation and respiratory depression, breastfeeding is not recommended. Consider alternative agents. |
| Lactation Rating | L5 (Avoid) |
| Teratogenic Risk | GENCEPT 10/11-21 contains ethinylestradiol (EE) and levonorgestrel (LNG). EE/LNG is contraindicated during pregnancy. First trimester: Risk of congenital anomalies (e.g., heart defects, limb reduction) from exogenous sex hormones. Second/Third trimester: Increased risk of fetal harm, including genital abnormalities in female fetuses from androgenic effects of progestins. Use should be discontinued immediately if pregnancy occurs. |
| Fetal Monitoring | Maternal: Blood pressure (risk of hypertension), liver function (hepatotoxicity), glucose tolerance (insulin resistance), and signs of thromboembolism. Fetal: Ultrasound if exposure occurs, assess for congenital anomalies. No routine monitoring required if used appropriately in non-pregnant women. |
| Fertility Effects | No adverse effects on fertility after discontinuation. Return to normal ovulation typically within 1-3 cycles. Long-term use does not impair future fertility. |
■ FDA Black Box Warning
Cigarette smoking increases the risk of serious cardiovascular events from combination hormonal contraceptive use. This risk increases with age, especially in women over 35, and with the number of cigarettes smoked. Women who use combination hormonal contraceptives should be strongly advised not to smoke.
| Serious Effects |
Hypersensitivity to active substance or excipientsConcurrent use of MAOIs or within 14 days of MAOI therapyNarrow-angle glaucomaSevere CNS depressionComatose states
| Precautions | Thrombotic disorders and cardiovascular events, Liver disease, Hypertension, Gallbladder disease, Carbohydrate and lipid effects, Headache/migraine, Bleeding irregularities, Ectopic pregnancy, Depression, Hereditary angioedema, Chloasma, Ocular effects, Drug interactions |
| Food/Dietary | No significant food interactions. However, grapefruit juice may increase ethinylestradiol levels; avoid excessive consumption (more than 1 liter per day). High-fat meals do not affect gestodene absorption. Maintain a consistent diet to avoid variability. |
| Clinical Pearls | GENCEPT 10/11-21 is an oral contraceptive containing ethinylestradiol and gestodene. Administer daily at the same time to maintain consistent hormone levels. Breakthrough bleeding is common in first 3 cycles; if persistent, consider alternative formulations. Missed doses increase pregnancy risk; follow standard missed pill protocol. Caution in smokers >35 years due to thromboembolic risk. Monitor blood pressure at baseline and annually. This product is not indicated for emergency contraception. |
| Patient Advice | Take one tablet daily at the same time, even during bleeding. · Missing a pill increases risk of pregnancy; refer to package insert for missed dose instructions. · Bleeding between periods may occur in early cycles; consult doctor if persistent. · Do not smoke while taking this medication, especially over age 35. · Inform doctor of all medications, including antibiotics and herbal supplements. · Seek immediate medical attention for signs of thrombosis: leg pain, chest pain, shortness of breath, or severe headache. |
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