Comparative Pharmacology
Head-to-head clinical analysis: GILDESS FE 1 5 30 versus GILDESS FE 1 20.
Peer-Reviewed Evidence
Head-to-head clinical analysis: GILDESS FE 1 5 30 versus GILDESS FE 1 20.
GILDESS FE 1.5/30 vs GILDESS FE 1/20
Head-to-head clinical comparison of therapeutic indices and safety profiles.
Combination oral contraceptive: ethinyl estradiol (estrogen) and levonorgestrel (progestin) suppress gonadotropin secretion (FSH and LH) via negative feedback, inhibiting ovulation, increasing cervical mucus viscosity, and altering endometrial receptivity.
Combination oral contraceptive: ethinyl estradiol suppresses gonadotropin release; norethindrone induces progestational changes in endometrium and cervical mucus, preventing ovulation and fertilization.
Prevention of pregnancy
Prevention of pregnancyTreatment of moderate acne vulgaris (for females ≥15 years old who have menarche and desire contraception)Oral contraceptive for women with iron deficiency anemia (as Gildess Fe 1/20 contains ferrous fumarate)
One tablet orally once daily at the same time each day for 21 consecutive days, followed by 7 days of placebo tablets.
One tablet orally once daily for 21 days followed by 7 placebo tablets per 28-day cycle.
None Documented
None Documented
Ethinyl estradiol: terminal elimination half-life approximately 13-27 hours (mean ~17 hours); clinical context: supports daily dosing with steady state achieved in ~1 week. Gestodene: terminal elimination half-life approximately 12-15 hours; clinical context: allows for maintaining stable serum concentrations with once-daily dosing.
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.
Ethinyl estradiol: primarily metabolized by CYP3A4; undergoes conjugation (glucuronidation and sulfation). Levonorgestrel: metabolized by reduction and conjugation; CYP3A4 involved.
Ethinyl estradiol undergoes CYP3A4-mediated hydroxylation; norethindrone is reduced and conjugated via glucuronidation and sulfation.
Ethinyl estradiol (EE) is primarily excreted in urine (40-45%) and feces (40-45%) as glucuronide and sulfate conjugates; less than 8% is excreted unchanged. Gestodene is extensively metabolized; its metabolites are excreted in urine (50-60%) and feces (30-40%), with less than 1% unchanged.
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%).
Ethinyl estradiol: 97-98% bound to albumin; gestodene: 65-75% bound to sex hormone-binding globulin (SHBG) and 25-35% bound to albumin; total binding ~99%.
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%).
Ethinyl estradiol: apparent Vd ~2.5-4.0 L/kg (mean ~3 L/kg); indicates extensive tissue distribution beyond plasma volume. Gestodene: apparent Vd ~0.7-1.0 L/kg; suggests moderate distribution to tissues.
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.
Ethinyl estradiol: oral bioavailability approximately 40-45% due to first-pass metabolism (sulfation and glucuronidation in gut wall and liver); interindividual variability significant. Gestodene: oral bioavailability nearly 100% (99-100%) due to minimal first-pass metabolism; high and consistent absorption.
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.
No dose adjustment required for mild to moderate renal impairment. Contraindicated in severe renal impairment (eGFR <30 mL/min/1.73 m²) due to potential estrogen-related fluid retention and hypertension.
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.
Contraindicated in Child-Pugh class B and C (moderate to severe hepatic impairment). Use with caution in Child-Pugh class A; closely monitor liver function.
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.
Not indicated for use before menarche. Post-menarche: same as adult dosing; one tablet orally once daily.
Approved for postmenarchal adolescents; dosing same as adults: one tablet orally once daily for 21 days followed by 7 placebo tablets.
Not indicated for use in postmenopausal women due to lack of efficacy for contraception and potential increased thromboembolic risk.
Not typically indicated for postmenopausal women due to ineffectiveness; if used in appropriate patients, no dose adjustment required but monitor for thromboembolic risks.
Cigarette smoking increases risk of serious cardiovascular events from combination oral contraceptive use. Risk increases with age (especially >35 years) and number of cigarettes smoked. Women >35 years who smoke should not use this product.
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.
["Thrombotic disorders (venous thromboembolism, arterial thromboembolism, stroke, myocardial infarction)","Carcinoma of the breast and reproductive organs","Hepatic neoplasia","Gallbladder disease","Carbohydrate and lipid metabolism effects","Elevated blood pressure","Headache","Bleeding irregularities","Ocular lesions (e.g., retinal thrombosis)","Depression"]
["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"]
["Thrombophlebitis or thromboembolic disorders","Cerebrovascular or coronary artery disease","Known or suspected breast cancer","Estrogen-dependent neoplasia","Undiagnosed abnormal genital bleeding","Pregnancy","Benign or malignant liver tumor","Hepatic impairment","Hypersensitivity to components","Women >35 years who smoke"]
["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"]
Data Pending Review
Data Pending Review
No significant food interactions. Grapefruit juice may slightly increase ethinyl estradiol levels but not clinically relevant. The iron component may cause gastrointestinal discomfort; taking with food can reduce this, but avoid taking with dairy (calcium) or caffeine as they may reduce iron absorption. Iron tablets should be taken with water or vitamin C source to enhance absorption, but not with tea, coffee, or milk.
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.
Pregnancy category X. Use contraindicated in pregnancy due to estrogenic effects on fetal development. First trimester: increased risk of congenital anomalies (cardiovascular, limb defects). Second and third trimesters: potential for fetal harm, including jaundice and liver dysfunction.
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.
Contraindicated in breastfeeding. Estrogen and progestin components reduce milk production and quality. Limited data; M/P ratio not established. Alternative contraception recommended.
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.
No dose adjustment due to contraindication in pregnancy. Pharmacokinetic changes in pregnancy (increased clearance) are not applicable as drug is not used.
Contraindicated in pregnancy; no dose adjustments indicated as use is not recommended. If inadvertently taken during pregnancy, discontinue immediately. No dosage changes are suggested for postpartum use, but alternative contraception should be considered during breastfeeding.
Category C
Category C
GILDESS FE 1.5/30 is a combination oral contraceptive containing ethinyl estradiol 30 mcg and gestodene 1.5 mg. Gestodene is a third-generation progestin with high progestational activity and minimal androgenic effects. The iron component (ferrous fumarate) is included to counteract menstrual blood loss. This formulation is associated with a lower risk of venous thromboembolism compared to second-generation pills but still carries a risk, particularly in smokers over 35. It should be taken at the same time daily to maintain efficacy. Breakthrough bleeding is common in the first few cycles; if persistent, rule out other causes. The iron tablets are not for contraceptive use and should be taken daily during the placebo week.
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.
Take one tablet daily at the same time, preferably after an evening meal to minimize nausea.If you miss a dose, follow the package instructions: if missed by less than 12 hours, take it immediately; if more than 12 hours, take the last missed pill and use backup contraception for 7 days.Use additional barrier contraception for the first 7 days of starting the pill, or if starting after day 5 of cycle, for the first cycle.Smoking increases the risk of serious cardiovascular side effects, especially if you are over 35 years old. Do not smoke while taking this medication.Seek immediate medical attention if you experience symptoms of a blood clot: sudden leg pain/swelling, chest pain, shortness of breath, or sudden severe headache.The iron tablets are not for contraception; they help replace iron lost during menstruation.Do not use this medication if you are pregnant, have a history of blood clots, certain migraines, liver disease, or hormone-sensitive cancer.Antibiotics (except rifampin) generally do not affect efficacy, but always consult your doctor if you are prescribed any new medication.
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.