GILDESS FE 1/20
Clinical safety rating
cautionComprehensive 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. |
| Molecular Weight | 310.39 |
| Action Class | Combination Oral Contraceptive (Estrogen-Progestin) |
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 | Contraindicated; risk of birth defects and fetal loss. Use only if no effective alternative and patient informed of risks. |
| 2nd trimester | Contraindicated; associated with female pseudohermaphroditism when used during fetal sexual differentiation. |
| 3rd trimester | Contraindicated; risk of teratogenicity, including clitoral hypertrophy, labial fusion, and potential long-term effects. |
Clinical note
Comprehensive clinical and safety monograph for GILDESS FE 1/20 (GILDESS FE 1/20).
| Placental transfer | Documented; crosses placenta and can reach fetal serum levels comparable to maternal levels. |
| Breastfeeding | Excreted in breast milk; may cause jaundice and breast enlargement in infants. Avoid use during breastfeeding. |
| Lactation Rating | L4 |
| 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. |
| 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. |
■ 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.
| Common Effects | Nausea, Headache, Breast tenderness, Weight changes, Irregular menstrual bleeding, Mood changes, Acne |
| Serious Effects | Venous thromboembolism (deep vein thrombosis, pulmonary embolism), Arterial thromboembolism (myocardial infarction, stroke), Hepatic adenoma or hepatocellular carcinoma, Hypertension, Gallbladder disease, Worsening of migraine headaches, Optic neuritis or retinal thrombosis |
Active or history of venous thromboembolismArterial thromboembolic disease (e.g., stroke, MI)Known or suspected pregnancyHypertension (uncontrolled)Diabetes with vascular involvementHepatic tumors (benign or malignant) or active liver diseaseUndiagnosed abnormal uterine bleedingKnown or suspected carcinoma of the breast or endometrium
| 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 |
| Food/Dietary | No significant food interactions. However, grapefruit juice may inhibit CYP3A4 metabolism and theoretically increase estrogen levels, but clinical significance is undetermined. Avoid St. John's wort, which reduces contraceptive efficacy. Caffeine metabolism may be decreased, leading to increased caffeine effects. No specific dietary restrictions required. |
| Clinical Pearls | Gildess FE 1/20 is a monophasic oral contraceptive containing 20 mcg ethinyl estradiol and 1 mg norethindrone acetate with ferrous fumarate placebos. It is indicated for contraception and may be used off-label for acne. The low estrogen dose may lead to more breakthrough bleeding, especially in the first few cycles. Advise patients to take at the same time daily and not to skip active pills. The iron in placebos can cause dark stools; warn patients. Missed pill management: if one active pill is missed, take it as soon as remembered; if two are missed, take two and use backup contraception for 7 days. Consider CYP3A4 inducers (e.g., rifampin, certain anticonvulsants) which reduce efficacy. Not recommended in patients with BMI > 35 due to increased failure risk. Do not use in smokers over 35 years old. Monitor blood pressure and for thrombotic events. |
| Patient Advice | Take one pill daily at the same time, even during withdrawal bleed weeks. · If you miss a pill, follow the package instructions: take the missed pill immediately and continue; if more than one missed, use backup contraception for 7 days. · The last 7 pills in the pack are placebo; they contain iron, so do not skip them but they don't provide contraceptive protection. · Iron in placebos may cause dark stools; this is harmless. · Common side effects: nausea, breast tenderness, headache, breakthrough bleeding (especially first 3 months). These often improve with time. · Contact your doctor if you have severe abdominal pain, chest pain, shortness of breath, severe headaches, vision changes, or leg pain/swelling. · This pill does not protect against sexually transmitted infections (STIs). Use condoms for STI prevention. · Avoid smoking while taking this medication, especially if over 35 years old. · Tell your doctor about all medications, especially antibiotics, antifungals, and seizure medications, as they may decrease effectiveness. · If you are undergoing surgery, inform your surgeon you are taking this pill. |
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