GILDESS 24 FE
Clinical safety rating
cautionComprehensive clinical and safety monograph for GILDESS 24 FE (GILDESS 24 FE).
Combination of ethinyl estradiol and drospirenone provides contraceptive effect primarily by suppression of gonadotropins (FSH and LH), inhibition of ovulation, and alterations in cervical mucus and endometrium. Drospirenone has antimineralocorticoid activity and antiandrogenic properties.
| Metabolism | Primarily metabolized via CYP3A4; drospirenone is also metabolized via CYP3A4 and sulfation. Ethinyl estradiol undergoes first-pass metabolism and is conjugated in the gut and liver. |
| Excretion | Renal: ~50-60% as metabolites (ethinyl estradiol glucuronide and sulfate conjugates, drospirenone metabolites); fecal: ~40-50% (drospirenone metabolites); biliary excretion contributes to enterohepatic circulation. |
| Half-life | Ethinyl estradiol: terminal half-life ~13-27 hours (mean ~17 hours); drospirenone: terminal half-life ~30-40 hours (mean ~32 hours). Clinical context: Steady-state achieved within 10 days for both components. |
| Protein binding | Ethinyl estradiol: ~98% bound (primarily albumin); drospirenone: ~95-97% bound (albumin and sex hormone-binding globulin, SHBG). |
| Volume of Distribution | Ethinyl estradiol: Vd ~2-4 L/kg (extensive tissue distribution); drospirenone: Vd ~4 L/kg (distributes to tissues, including breast and reproductive organs). |
| Bioavailability | Oral: Ethinyl estradiol ~45-50% (first-pass metabolism); drospirenone ~76-85% (high oral bioavailability, limited first-pass effect). |
| Onset of Action | Oral: Ovulation suppression achieved after 7 days of continuous dosing. Clinical effect (contraception) requires 7 days of consistent use. |
| Duration of Action | Oral: Contraceptive effect persists for 24 hours after each dose. Missed dose guidelines: If dose delayed >12 hours, backup contraception needed for 7 days. |
| Molecular Weight | Ethinyl estradiol: 296.41 Da; Drospirenone: 366.49 Da |
| Action Class | Oral Contraceptive; Estrogen/Progestin Combination |
One tablet orally once daily for 24 days, followed by 4 days of placebo (iron tablets). The active tablets contain 0.8 mg norethindrone acetate and 0.025 mg ethinyl estradiol.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment. Not studied in severe renal impairment; use with caution due to potential fluid retention and hormonal changes. |
| Liver impairment | Contraindicated in Child-Pugh Class B or C (moderate to severe hepatic impairment). For mild impairment (Child-Pugh A), no dose adjustment but monitor liver function. |
| Pediatric use | Safety and efficacy not established in postmenarcheal females less than 18 years of age. Use is generally not recommended before menarche. |
| Geriatric use | Not indicated for use in postmenopausal women. No specific geriatric dosing; use is not recommended in this population. |
| 1st trimester | Contraindicated due to risk of birth defects (limb defects, cardiovascular anomalies) from estrogen/progestin exposure during organogenesis. |
| 2nd trimester | Contraindicated; risks of adverse fetal outcomes including low birth weight and preterm delivery. |
| 3rd trimester | Contraindicated; may cause fetal harm including withdrawal bleeding and potential for masculinization of female fetus. |
Clinical note
Comprehensive clinical and safety monograph for GILDESS 24 FE (GILDESS 24 FE).
| Placental transfer | Established; both ethinyl estradiol and drospirenone cross the placenta. Studies show measurable concentrations in fetal tissues. |
| Breastfeeding | Small amounts of ethinyl estradiol and drospirenone are excreted in breast milk, potentially reducing milk production and altering infant hormones. Use is generally not recommended; alternative contraception should be considered. |
| Lactation Rating | L4 |
| Teratogenic Risk | FDA Pregnancy Category X. Contraindicated in pregnancy. First trimester: Increased risk of congenital anomalies (cardiovascular defects, neural tube defects) from estrogen/progestin exposure. Second/third trimester: No direct fetal toxicity reported. Postpartum: Excreted in breast milk, but no adverse effects documented. |
| Fetal Monitoring | Maternal: Blood pressure, weight, glucose tolerance, lipid profile, hepatic function, and menstrual pattern. Fetal: Not applicable (contraindicated in pregnancy). Rule out pregnancy before initiation. |
| Fertility Effects | Reversible suppression of ovulation via GnRH inhibition. Short-term use (≤1 year) does not impair subsequent fertility. After discontinuation, 80% conceive within 12 months. No permanent effect on oocyte quality or uterine receptivity. |
■ FDA Black Box Warning
Cigarette smoking increases the risk of serious cardiovascular events from combination oral contraceptive use. This risk increases with age and with heavy smoking (15 or more cigarettes per day) and is quite marked in women over 35 years of age. Women who use combination oral contraceptives should be strongly advised not to smoke.
| Common Effects | Nausea, Headache, Breast tenderness, Irregular bleeding or spotting, Weight changes, Mood changes |
| Serious Effects | Venous thromboembolism (VTE), Arterial thromboembolism (e.g., stroke, myocardial infarction), Hypertension, Hepatic adenoma or hepatocellular carcinoma, Gallbladder disease, Hyperkalemia (due to drospirenone's antimineralocorticoid activity) |
PregnancyThrombophlebitis or thromboembolic disordersKnown or suspected estrogen-dependent neoplasia (e.g., breast cancer)Abnormal genital bleeding of unknown etiologyHepatic adenoma or carcinomaActive liver disease with abnormal liver functionHypersensitivity to any component
| Precautions | Thrombotic and other vascular events (e.g., myocardial infarction, stroke, venous thromboembolism), Risk for hyperkalemia in patients with renal/hepatic impairment or on medications that increase potassium, Liver disease (e.g., acute hepatitis, cholestatic jaundice), Hypertension, Carbohydrate and lipid metabolic effects, Headache (including migraine), Bleeding irregularities, Depression, Gallbladder disease, Hereditary angioedema |
| Food/Dietary | No significant food interactions. Grapefruit juice may increase estrogen levels, but clinical significance is low. Avoid St. John's wort as it can reduce contraceptive efficacy. |
| Clinical Pearls | GILDESS 24 FE is a combined oral contraceptive containing ethinyl estradiol and desogestrel. Iron supplementation (ferrous fumarate) in the placebo pills may cause constipation or black stools. Monitor for thromboembolic events, especially in smokers over 35. Efficacy may be reduced with enzyme-inducing drugs. Missed pill protocol: if missed one active pill, take as soon as remembered; if missed two or more, take last missed pill and use backup contraception for 7 days. |
| Patient Advice | Take one pill daily at the same time, even if not sexually active. · If you miss a pill, refer to the package insert for instructions; use backup contraception if needed. · Iron pills in the placebo week may cause dark stools or constipation; inform your doctor if symptoms persist. · Do not smoke while taking this medication, especially if over 35, due to increased risk of blood clots. · Common side effects include nausea, breast tenderness, and breakthrough bleeding; these often improve after 3 months. · Seek immediate medical attention for signs of blood clot: leg pain/swelling, sudden chest pain, shortness of breath, or severe headache. |
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