DESOGEN
Clinical safety rating
cautionComprehensive clinical and safety monograph for DESOGEN (DESOGEN).
Progestin (desogestrel) combined with ethinyl estradiol inhibits gonadotropin release, suppressing ovulation. Also increases cervical mucus viscosity, impeding sperm penetration.
| Metabolism | Desogestrel is a prodrug rapidly metabolized to its active metabolite, etonogestrel, primarily by cytochrome P450 enzymes (CYP2C9 and CYP2C19). Ethinyl estradiol is metabolized by CYP3A4 and undergoes glucuronidation. |
| Excretion | Desogestrel is primarily metabolized to its active metabolite etonogestrel, which is extensively metabolized and excreted as conjugates. About 50-60% is excreted via urine and 30-40% via feces. Less than 1% is excreted unchanged. |
| Half-life | The terminal elimination half-life of etonogestrel is approximately 30-41 hours. This long half-life supports once-daily dosing for contraceptive efficacy. |
| Protein binding | Etonogestrel is 95-98% bound to plasma proteins, primarily albumin and sex hormone-binding globulin (SHBG). Desogestrel itself is about 80% bound to albumin. |
| Volume of Distribution | The apparent volume of distribution of etonogestrel is approximately 1.3-1.6 L/kg. This relatively large Vd indicates extensive tissue distribution. |
| Bioavailability | Oral bioavailability of desogestrel is essentially complete due to rapid and extensive metabolism to etonogestrel. The absolute bioavailability of etonogestrel after oral desogestrel is about 76-80%. |
| Onset of Action | Oral administration: Onset of contraceptive effect occurs after 7 days of continuous dosing. For immediate effect when initiated on day 1 of menstrual cycle, additional barrier contraception is recommended for the first 7 days. |
| Duration of Action | Contraceptive protection persists for the entire 21-day dosing cycle and for the 7-day placebo period. Follicular suppression may last up to 2 weeks after discontinuation, but return of fertility typically occurs in the next cycle. |
| Molecular Weight | 310.48 |
One tablet (0.15 mg desogestrel and 0.03 mg ethinyl estradiol) orally once daily for 21 consecutive days, followed by 7 hormone-free days.
| 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 estrogen accumulation. |
| Liver impairment | Contraindicated in Child-Pugh class B and C (moderate to severe hepatic impairment). Use with caution in Child-Pugh class A; monitor liver function. |
| Pediatric use | Only after menarche. Same dosing as adults: one tablet daily for 21 days, then 7 days off. No weight-based dosing; use standard adult dose. |
| Geriatric use | Not indicated for use after menopause. For perimenopausal women, same adult dosing applies; monitor for increased thromboembolic risk. |
| 1st trimester | Risk cannot be ruled out. Animal studies have shown teratogenic effects at high doses. Use only if benefit outweighs risk. |
| 2nd trimester | Use only if clearly needed. No well-controlled studies in pregnant women. |
| 3rd trimester | Avoid use. May increase risk of thrombotic events and fetal abnormalities. Prolonged exposure may affect fetal development. |
Clinical note
Comprehensive clinical and safety monograph for DESOGEN (DESOGEN).
| Placental transfer | Desogestrel and its metabolites cross the placenta. Fetal concentrations are approximately 20-30% of maternal serum levels based on limited studies. |
| Breastfeeding | Desogestrel is excreted into breast milk in small amounts. Use with caution in nursing mothers, especially in the early postpartum period. Monitor infant for jaundice and weight gain. |
| Lactation Rating | L3 - Moderately Safe |
| Teratogenic Risk | Pregnancy category X. First trimester: Known risk of fetal harm, including cardiovascular defects and limb reduction defects. Second and third trimesters: Increased risk of fetal death, jaundice, and neurodevelopmental issues. Contraindicated in pregnancy. |
| Fetal Monitoring | Monitor for signs of pregnancy; exclude pregnancy before initiation. Assess for thrombotic events, liver function, and blood pressure regularly. Fetal monitoring if inadvertent exposure occurs. |
| Fertility Effects | Desogestrel is used as a contraceptive and can affect ovulation and implantation. After discontinuation, fertility returns quickly, typically within one menstrual cycle. No long-term negative effects on fertility. |
■ FDA Black Box Warning
Cigarette smoking increases risk of serious cardiovascular events from combination oral contraceptives. Risk increases with age (especially >35 years) and number of cigarettes smoked. Women who use COCs should be strongly advised not to smoke.
| Serious Effects |
Known or suspected pregnancyActive thrombophlebitis or thromboembolic disordersHistory of deep vein thrombosis or pulmonary embolismCerebrovascular or coronary artery diseaseKnown or suspected carcinoma of the breast or endometriumUndiagnosed abnormal genital bleedingActive liver disease or hepatic adenomasHypersensitivity to desogestrel or any component
| Precautions | Increased risk of thromboembolic disorders (e.g., stroke, MI, DVT, PE), Increased risk of cervical cancer and hepatocellular carcinoma, Elevated blood pressure, Gallbladder disease, Carbohydrate and lipid metabolism effects, Headache, including migraine, Altered menstrual bleeding patterns, Depression, Contact lens intolerance, Hereditary angioedema, Chloasma, Hepatic impairment, Pregnancy (discontinue if pregnancy occurs), Lactation (may decrease milk production) |
| Food/Dietary | No significant food interactions. Grapefruit juice may increase estrogen levels via CYP3A4 inhibition, but clinical relevance is minimal. Maintain consistent dietary habits to avoid fluctuations in hormone levels. |
| Clinical Pearls | Desogen (desogestrel/ethinyl estradiol) is a combined oral contraceptive. For patients with a history of venous thromboembolism, avoid use. Consider progestin-only alternative if contraindication to estrogen exists. Counsel on increased risk of breakthrough bleeding with missed doses. Monitor blood pressure at baseline and annually. |
| Patient Advice | Take one tablet daily at the same time to maintain hormone levels. · If a dose is missed, follow package instructions; use backup contraception if needed. · Report symptoms of blood clots: leg pain/swelling, chest pain, sudden shortness of breath. · Avoid smoking, especially if over 35, due to increased cardiovascular risk. · May cause nausea, breast tenderness, or mood changes; usually resolves within 3 cycles. |
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