GILDESS 1/20
Clinical safety rating
cautionComprehensive clinical and safety monograph for GILDESS 1/20 (GILDESS 1/20).
GILDESS 1/20 is a combination oral contraceptive containing ethinyl estradiol (an estrogen) and gestodene (a progestin). Its primary mechanism is inhibition of ovulation via suppression of gonadotropin-releasing hormone (GnRH), leading to reduced follicle-stimulating hormone (FSH) and luteinizing hormone (LH) secretion. Additionally, it alters cervical mucus (increasing viscosity to impede sperm penetration) and endometrial structure (rendering it unsuitable for implantation).
| Metabolism | Both ethinyl estradiol and gestodene are metabolized primarily in the liver via the cytochrome P450 3A4 (CYP3A4) pathway. Ethinyl estradiol undergoes first-pass metabolism and enterohepatic recirculation; gestodene is hydroxylated and conjugated. |
| Excretion | Renal (estradiol: ~40-50% as glucuronide and sulfate conjugates; gestodene: ~30-40% as metabolites) and fecal (estradiol: ~20-30%; gestodene: ~30-40%). Less than 1% excreted unchanged. |
| Half-life | Ethinylestradiol: terminal half-life ~13-27 hours (mean 17 hours). Gestodene: terminal half-life ~12-15 hours. Steady-state reached within 5-7 days. |
| Protein binding | Ethinylestradiol: 98% bound to albumin. Gestodene: 75-90% bound to sex hormone-binding globulin (SHBG) and albumin. |
| Volume of Distribution | Ethinylestradiol: ~2.4 L/kg. Gestodene: ~0.7 L/kg. Indicates extensive tissue distribution. |
| Bioavailability | Oral: Ethinylestradiol ~40-60% (first-pass metabolism). Gestodene ~99% (highly bioavailable due to minimal first-pass effect). |
| Onset of Action | Oral: Contraceptive effect begins after 7 days of continuous dosing if started on day 1 of menstrual cycle; follicle suppression occurs within 2-3 days. |
| Duration of Action | Oral: Provides contraceptive coverage for 21 days of active pills; followed by 7-day placebo interval. Maximal suppression of ovulation persists for at least 7 days after last active dose. |
| Molecular Weight | Ethinylestradiol: 296.4 Da; Desogestrel: 310.5 Da; combined molecular weight not additive. |
| Action Class | Combined oral contraceptive (COC) - estrogen/progestin combination |
One tablet orally daily, each containing 20 mcg ethinyl estradiol and 150 mcg desogestrel.
| Dosage form | TABLET |
| Renal impairment | No dosage adjustment required for mild-to-moderate renal impairment. Insufficient data for severe renal impairment; use with caution. |
| Liver impairment | Contraindicated in hepatic adenomas, active liver disease, or Child-Pugh class B/C cirrhosis. For mild hepatic impairment (Child-Pugh A), no dosage adjustment; monitor. |
| Pediatric use | Not indicated for use in pediatric patients before menarche. Post-menarche, same as adult dosing; use only after establishment of regular menstrual cycles. |
| Geriatric use | Not indicated for use in postmenopausal women. No specific geriatric dosing; generally not used in elderly women due to increased risk of thromboembolism. |
| 1st trimester | Avoid use: contains ethinylestradiol and desogestrel, known to cause congenital anomalies; risk of cardiovascular and limb defects. |
| 2nd trimester | Contraindicated: risk of fetal harm and pregnancy complications; estrogens can affect fetal development. |
| 3rd trimester | Contraindicated: potential for adverse effects on fetal development and complications during labor. |
Clinical note
Comprehensive clinical and safety monograph for GILDESS 1/20 (GILDESS 1/20).
| Placental transfer | Ethinylestradiol and desogestrel cross the placenta; desogestrel is a progestin with demonstrable placental transfer. |
| Breastfeeding | Excreted in breast milk; may reduce milk production and quality; use alternative contraception in breastfeeding women. |
| Lactation Rating | L4 - Possibly Hazardous |
| Teratogenic Risk | GILDESS 1/20 (ethinyl estradiol 20 mcg/desogestrel 0.15 mg) is category X in pregnancy. First trimester: increased risk of congenital anomalies (e.g., heart defects, limb reduction) from estrogen component; cardiovascular and nervous system malformations reported. Second and third trimesters: associated with masculinization of female fetus from progestin; increased risk of IUGR and preterm birth. Use contraindicated in pregnancy. |
| Fetal Monitoring | If inadvertently used during pregnancy: detailed fetal anatomy ultrasound; consider amniocentesis if anomalies suspected. Monitor for signs of IUGR, preterm labor. Assess maternal coagulation panel if thrombotic events suspected. No routine monitoring required if used non-pregnant. |
| Fertility Effects | Reversible suppression of ovulation; normal fertility returns within 1-2 cycles after discontinuation. No long-term adverse effects on fertility. May improve cycle regularity in some conditions. |
■ 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 cigarettes per day) and is particularly pronounced 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, Breakthrough bleeding or spotting, Weight changes, Mood changes |
| Serious Effects | Venous thromboembolism (VTE), Arterial thromboembolism (e.g., stroke, myocardial infarction), Hepatic adenoma or hepatocellular carcinoma, Hypertension, Gallbladder disease, Cerebrovascular events |
Known or suspected pregnancyThrombophlebitis or thromboembolic disordersCerebrovascular or coronary artery diseaseBreast cancer (known or suspected)Estrogen-dependent neoplasiaUndiagnosed abnormal genital bleedingHepatic adenoma or carcinomaActive liver disease with impaired functionControlled hypertension (≥160/100 mmHg) not on therapyCholestatic jaundice of pregnancy or jaundice with prior OCsSmoking and age ≥35
| Precautions | Risk of thromboembolic disorders (venous and arterial), including myocardial infarction and stroke, Increased risk of hypertension and associated vascular complications, Potential hepatic neoplasia (benign and malignant), Possible exacerbation of cholestatic jaundice or gallbladder disease, May cause fluid retention, which can aggravate conditions such as migraine, asthma, cardiac, or renal dysfunction, Altered carbohydrate metabolism: monitor glucose in diabetic patients, May worsen depression or epilepsy |
| Food/Dietary | No specific food interactions are reported for GILDESS 1/20. However, grapefruit juice may increase estrogen levels; advise patients to consume grapefruit products in moderation. Alcohol may impair judgment regarding missed doses; recommend moderate intake. |
| Clinical Pearls | GILDESS 1/20 is a monophasic oral contraceptive containing 20 mcg ethinyl estradiol and 1 mg norethindrone acetate. It is indicated for contraception and may be used for acne vulgaris in women at least 15 years old. Monitor for breakthrough bleeding, especially in the first cycles. Counsel patients to take at the same time daily to maintain efficacy. Caution in women with migraine with aura, hypertension, or history of thromboembolism. Prescribe as a 21-day regimen with a 7-day hormone-free interval. |
| Patient Advice | Take one pill at the same time every day, even if you do not have sex often. · If you miss a pill, follow the instructions in the package insert or consult your healthcare provider. · Use a backup method (like condoms) if you miss more than one pill or start late. · Common side effects include nausea, breast tenderness, and spotting, especially in the first few cycles. · Contact your doctor if you experience severe abdominal pain, chest pain, headache, vision changes, or leg pain/swelling. · Smoking increases the risk of serious cardiovascular side effects; avoid smoking while on this medication. · Do not take GILDESS if you are pregnant or suspect pregnancy. |
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