GILDESS FE 1/20
Clinical safety rating: caution
Comprehensive clinical and safety monograph for GILDESS FE 1/20 (GILDESS FE 1/20).
Combination oral contraceptive: ethinyl estradiol suppresses gonadotropin release; norethindrone induces progestational changes in endometrium and cervical mucus, preventing ovulation and fertilization.
| Metabolism | Ethinyl estradiol undergoes CYP3A4-mediated hydroxylation; norethindrone is reduced and conjugated via glucuronidation and sulfation. |
| Excretion | Approximately 60-65% renal (as metabolites), 30-35% fecal (as metabolites and unchanged drug). Ethinyl estradiol and desogestrel metabolites are excreted primarily via urine and feces. Etonogestrel (active metabolite) is excreted mainly via feces (40%) and urine (32%). |
| Half-life | Ethinyl estradiol: terminal half-life approximately 13 hours (range 10-15 h). Desogestrel: metabolized to etonogestrel; etonogestrel terminal half-life about 28 hours (range 20-40 h). Clinical context: steady-state reached within 7-10 days. |
| Protein binding | Ethinyl estradiol: 97-98% bound to albumin, with specific binding to sex hormone-binding globulin (SHBG). Etonogestrel: >95% bound, primarily to albumin (60-70%) and SHBG (30-40%). |
| Volume of Distribution | Ethinyl estradiol: apparent Vd approximately 2.5 L/kg (range 2.1-3.0 L/kg). Desogestrel: Vd for etonogestrel is about 2.0 L/kg. High Vd indicates extensive tissue distribution, including adipose and reproductive tissues. |
| Bioavailability | Oral: Ethinyl estradiol bioavailability approximately 45-55% due to first-pass metabolism (sulfation and glucuronidation). Desogestrel: prodrug, bioavailability of etonogestrel is about 76-84% after oral dose. No other relevant routes. |
| Onset of Action | Oral: contraceptive effect begins after 7 consecutive days of dosing. For ovulation suppression, maximum effect after 14 days of continuous use. No immediate effect; requires adherence to initial 7-day window. |
| Duration of Action | The contraceptive effect persists for 7 days after the last active pill (7-day hormone-free interval). Ovulation suppression lasts for up to 7 days post-discontinuation. Clinical note: If a pill is missed, backup contraception needed beyond 7 days. |
One tablet orally once daily for 21 days followed by 7 placebo tablets per 28-day cycle.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment. Contraindicated in severe renal impairment (CrCl <30 mL/min) due to potential for fluid retention. |
| Liver impairment | Contraindicated in severe hepatic impairment (Child-Pugh class C). Caution in moderate impairment (Child-Pugh class B) due to altered hormone metabolism; use alternative methods if possible. |
| Pediatric use | Approved for postmenarchal adolescents; dosing same as adults: one tablet orally once daily for 21 days followed by 7 placebo tablets. |
| Geriatric use | Not typically indicated for postmenopausal women due to ineffectiveness; if used in appropriate patients, no dose adjustment required but monitor for thromboembolic risks. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for GILDESS FE 1/20 (GILDESS FE 1/20).
| Breastfeeding | Excreted in breast milk in small amounts (estrogen and progestin). M/P ratio not well-defined. Use may reduce milk production and quality, especially in early postpartum period. Consider alternative contraception during breastfeeding, especially in first 6 months. Use only if benefits outweigh risks, with close monitoring of infant growth and development. |
| Teratogenic Risk | FDA Pregnancy Category X. Contraindicated in pregnancy due to risk of fetal harm. First trimester: Increased risk of neural tube defects, congenital heart defects, and limb reduction defects from progestin component. Second and third trimesters: Risk of fetal feminization (masculinization of female fetuses) from androgen-like effects of progestin; also associated with increased risk of neonatal hepatoblastoma and possibly other tumors. Combination hormonal contraceptives should be discontinued immediately if pregnancy occurs. |
■ FDA Black Box Warning
Cigarette smoking increases risk of serious cardiovascular events from combination oral contraceptives. Risk increases with age and smoking intensity (≥15 cigarettes/day) and is significant in women >35 years old. Women >35 who smoke should not use this product.
| Serious Effects |
["Thrombophlebitis or thromboembolic disorders","Cerebrovascular or coronary artery disease","Known or suspected breast carcinoma","Endometrial or other estrogen-dependent neoplasia","Undiagnosed abnormal genital bleeding","Pregnancy or suspected pregnancy","Benign or malignant liver tumor","Active liver disease","Hypersensitivity to any component","Smoking in women >35 years"]
| Precautions | ["Thrombotic disorders (thrombophlebitis, venous thromboembolism, stroke, MI)","Carcinoma of the breast and reproductive organs","Hepatic disease (adenoma, hepatocellular carcinoma)","Ocular lesions (retinal thrombosis)","Gallbladder disease","Carbohydrate and lipid effects","Elevated blood pressure","Headache/migraine","Bleeding irregularities","Depression","Hereditary angioedema","Chloasma","Hepatic function impairment","Iron supplementation (Fe fumarate): may cause GI upset, constipation, and dark stools"] |
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| Fetal Monitoring | Pregnancy test before initiation. Liver function tests, renal function, and blood pressure monitoring at baseline and periodically. Monitor for signs of thromboembolism, hypertension, and glucose intolerance. In case of pregnancy, discontinue immediately and perform ultrasound to rule out fetal anomalies. No routine fetal monitoring required otherwise. |
| Fertility Effects | Reversibly suppresses ovulation and alters cervical mucus and endometrium. After discontinuation, return of fertility is typically immediate or within 1-3 months. No permanent impact on fertility, though there may be a slight delay in return of ovulatory cycles, especially with long-term use. |