MIRCETTE
Clinical safety rating
cautionComprehensive clinical and safety monograph for MIRCETTE (MIRCETTE).
Combination of ethinyl estradiol and desogestrel; estrogen and progestin inhibit gonadotropin release, suppressing ovulation and altering cervical mucus and endometrial receptivity.
| Metabolism | Ethinyl estradiol: primarily metabolized via CYP3A4; undergoes first-pass hepatic metabolism, conjugated to sulfate and glucuronide. Desogestrel: prodrug converted to active metabolite etonogestrel via CYP2C9 and CYP3A4; further metabolized by reduction and glucuronidation. |
| Excretion | Urine (50-60% as metabolites, <10% unchanged), feces (30-40% as metabolites) |
| Half-life | Desogestrel active metabolite etonogestrel: 21-24 hours; ethinyl estradiol: 12-14 hours |
| Protein binding | Desogestrel: >95% (albumin, SHBG); ethinyl estradiol: >97% (albumin) |
| Volume of Distribution | Desogestrel: 1.5 L/kg; ethinyl estradiol: 2.9 L/kg |
| Bioavailability | Desogestrel (as etonogestrel): 76% (oral); ethinyl estradiol: 55% (oral, variable due to first-pass metabolism) |
| Onset of Action | Oral administration: 7 days of continuous use for contraceptive effect (inhibition of ovulation) |
| Duration of Action | Contraceptive effect persists for 7 days after last pill if taken correctly; withdrawal bleed occurs during placebo week |
| Molecular Weight | 310.48 |
One tablet daily for 21 days, followed by 7 placebo tablets. Each active tablet contains 0.015 mg ethinyl estradiol and 2 mg chlormadinone acetate. Route: oral.
| Dosage form | TABLET |
| Renal impairment | No specific dose adjustment recommended. Use with caution in severe renal impairment due to potential fluid retention. |
| Liver impairment | Contraindicated in severe hepatic disease (Child-Pugh class C) or liver tumors. For mild to moderate impairment (Child-Pugh A-B), use with caution; contraindicated if liver function tests are persistently abnormal. |
| Pediatric use | Not indicated in prepubertal females. Safety and efficacy in postmenarchal adolescents established based on adult studies. |
| Geriatric use | Contraindicated in postmenopausal women. Not indicated for use in elderly due to lack of efficacy for contraception. |
| 1st trimester | Mircette (desogestrel/ethinyl estradiol) is contraindicated in pregnancy. Use during first trimester may be associated with congenital defects, but current evidence does not strongly support a causal link. However, due to potential risk, it should not be used in pregnant women. |
| 2nd trimester | Use in second trimester is contraindicated as it can cause fetal harm. There is a risk of masculinization of female fetuses due to progestin component. |
| 3rd trimester | Use in third trimester is contraindicated. Estrogens can delay or arrest parturition and increase risk of thromboembolic complications in mother and infant. |
Clinical note
Comprehensive clinical and safety monograph for MIRCETTE (MIRCETTE).
| Placental transfer | Both desogestrel and ethinyl estradiol cross the placenta. Desogestrel is metabolized to etonogestrel, which has measurable fetal concentrations. Ethinyl estradiol also demonstrates placental transfer. |
| Breastfeeding | Mircette (desogestrel/ethinyl estradiol) passes into breast milk in small amounts. Estrogens may reduce milk production and quality, especially in early postpartum period. Combination hormonal contraceptives are generally not recommended during breastfeeding due to potential adverse effects on milk supply and infant. Progestin-only contraceptives are preferred. |
| Lactation Rating | L4 - Possibly Hazardous |
| Teratogenic Risk | FDA Pregnancy Category X. Contraindicated in pregnancy. First trimester exposure associated with congenital anomalies (cardiovascular, limb reduction, neural tube defects). Second/third trimester exposure may cause fetal adrenal suppression, virilization of female fetus, and metabolic disturbances. |
| Fetal Monitoring | Pregnancy testing before initiation and periodically during therapy. Ultrasound for fetal development if accidental exposure occurs. Monitor maternal blood pressure, glucose, and liver function. Assess fetal heart rate if late exposure. |
| Fertility Effects | Reversible suppression of ovulation. Return to fertility typically within 2-3 cycles after discontinuation. Long-term use may delay return to fertility but no permanent effect. |
■ FDA Black Box Warning
Cigarette smoking increases risk of serious cardiovascular events from COC use, especially in women >35 years old who smoke ≥15 cigarettes/day. Do not prescribe to women who smoke and are over 35.
| Serious Effects |
Known or suspected pregnancyThrombophlebitis or thromboembolic disorders (current or history)Cerebrovascular or coronary artery diseaseKnown or suspected carcinoma of the breastCarcinoma of the endometrium or other estrogen-dependent neoplasiaUndiagnosed abnormal genital bleedingHepatic adenoma or carcinomaActive liver disease or impaired liver functionKnown hypersensitivity to any component of MircetteSmoking in women over 35 years of ageMigraine with focal auraDiabetes with vascular involvementUncontrolled hypertensionMajor surgery with prolonged immobilizationKnown thrombogenic mutations (e.g., Factor V Leiden, prothrombin mutation, protein C/S deficiency)
| Precautions | Increased risk of thrombotic disorders (VTE, MI, stroke), especially in smokers and women with hypertension or other risk factors., Liver disease: discontinue if jaundice or impaired liver function develops., Elevated blood pressure: monitor and discontinue if hypertension develops., Gallbladder disease: possible increased risk., Carbohydrate and lipid metabolism: monitor in diabetic or hyperlipidemic patients., Headache: may exacerbate migraine or cause new-onset headache., Uterine bleeding: irregular bleeding may occur., Depression: discontinue if significant depression occurs., Ocular effects: discontinue if sudden partial/complete vision loss occurs., Carcinoma: possible increased risk of breast/cervical cancer, but evidence uncertain. |
| Food/Dietary | No significant food interactions known; however, grapefruit juice may increase estrogen levels via CYP3A4 inhibition, though clinical significance is low. Avoid St. John's wort as it induces metabolism of ethinyl estradiol and desogestrel, potentially reducing contraceptive efficacy. |
| Clinical Pearls | Mircette is a monophasic oral contraceptive containing 0.15 mg desogestrel and 0.02 mg ethinyl estradiol. It has a shorter hormone-free interval (2 days of placebo) than traditional 7-day placebo regimens, which may reduce breakthrough ovulation and improve suppression of ovarian activity. Counsel patients that the first 7 days of the initial cycle may require a backup method. Desogestrel has low androgenicity and may improve acne. Use with caution in patients with migraine with aura or increased cardiovascular risk. |
| Patient Advice | Take one tablet at the same time daily; missed pills increase pregnancy risk. · If you miss a pill, refer to the package insert for instructions; use backup contraception if needed. · Mircette may reduce menstrual bleeding and cramping; do not skip pills during withdrawal bleeding. · Smoking while on this pill increases risk of blood clots, especially in women over 35. · Some antibiotics and anticonvulsants may reduce effectiveness; inform your healthcare provider of all medications. · Do not take if you have a history of blood clots, certain cancers, or liver disease. |
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