OGESTREL 0.5/50-21
Clinical safety rating
cautionComprehensive clinical and safety monograph for OGESTREL 0.5/50-21 (OGESTREL 0.5/50-21).
Combination of norgestrel and ethinyl estradiol suppresses gonadotropin release, inhibiting ovulation; alters cervical mucus and endometrial lining.
| Metabolism | Hepatic, via CYP3A4; norgestrel undergoes reduction, conjugation; ethinyl estradiol is metabolized by CYP3A4 and undergoes glucuronidation. |
| Excretion | Renal: ~50% (metabolites); Fecal/Biliary: ~50% (metabolites); <1% unchanged in urine. |
| Half-life | Norgestrel: 24-32 hours; Ethinyl estradiol: 7-12 hours. Clinical context: Steady state achieved after 5-7 days. |
| Protein binding | Norgestrel: 93-95% to albumin and SHBG; Ethinyl estradiol: 97-98% to albumin. |
| Volume of Distribution | Norgestrel: 2.5-3.5 L/kg; Ethinyl estradiol: 2.5-4 L/kg. Indicates extensive tissue distribution. |
| Bioavailability | Oral: Norgestrel ~95%; Ethinyl estradiol ~40-60% due to first-pass metabolism. |
| Onset of Action | Oral: Maximal contraceptive effect within 7 days if started on day 1 of menses. |
| Duration of Action | Oral: Duration of contraceptive effect with daily dosing; missed pills increase pregnancy risk. |
| Molecular Weight | 340.46 |
One tablet (norgestrel 0.5 mg / ethinyl estradiol 0.05 mg) orally once daily for 21 days, followed by 7 placebo days.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment; contraindicated in severe renal disease due to potential fluid retention. |
| Liver impairment | Contraindicated in acute or chronic hepatic disease; do not use in Child-Pugh class B or C. Use with caution in mild impairment (Child-Pugh A) at minimal effective dose. |
| Pediatric use | Not indicated for use before menarche. For postmenarchal adolescents, same dosing as adults (one tablet daily for 21 days). |
| Geriatric use | Not indicated for use after menopause. In elderly patients, evaluate cardiovascular and hepatic status; consider lower estrogen dose if necessary. |
| 1st trimester | Contraindicated; risk of fetal harm due to hormonal effects. Use during pregnancy may cause congenital anomalies, including cardiac defects and limb reduction defects. |
| 2nd trimester | Contraindicated; continued exposure may affect fetal development and should be avoided during pregnancy. |
| 3rd trimester | Contraindicated; use near term may cause neonatal withdrawal symptoms and hormonal disturbances. |
Clinical note
Comprehensive clinical and safety monograph for OGESTREL 0.5/50-21 (OGESTREL 0.5/50-21).
| Placental transfer | Yes, crosses the placenta readily. Norethindrone and ethinyl estradiol are detected in fetal plasma and tissues. |
| Breastfeeding | Excreted into breast milk in small amounts. May reduce milk production and composition. Use caution in nursing mothers; consider risk of potential adverse effects in the infant, including jaundice and hormonal effects. |
| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | Pregnancy category X. Contraindicated in pregnancy due to known teratogenicity. First trimester: limb defects, cardiac anomalies; second/third trimester: feminization of male fetus, urogenital abnormalities. |
| Fetal Monitoring | Monitor for thromboembolism, hypertension, glucose intolerance, hepatic dysfunction. Ultrasound if inadvertent use in early pregnancy. |
| Fertility Effects | Suppresses ovulation. Reversible after discontinuation; no long-term effect on fertility. |
■ FDA Black Box Warning
Cigarette smoking increases risk of serious cardiovascular events from combination oral contraceptives; risk increases with age and heavy smoking (≥15 cigarettes/day); women over 35 who smoke should not use this product.
| Serious Effects |
PregnancyThrombophlebitis or thromboembolic disordersBreast cancer (current or history)Estrogen-dependent neoplasiaUndiagnosed abnormal genital bleedingHepatic adenoma or carcinomaActive liver disease or impaired liver functionKnown hypersensitivity to components
| Precautions | Increased risk of thromboembolic disorders; hepatic neoplasia; elevated blood pressure; gallbladder disease; carbohydrate and lipid metabolism effects; breakthrough bleeding and spotting; use in pregnancy; depression; contact lens intolerance; fluid retention; hereditary angioedema. |
| Food/Dietary | Grapefruit juice may inhibit CYP3A4 metabolism of ethinyl estradiol, potentially increasing estrogen exposure and risk of adverse effects. Avoid large quantities (e.g., >1 quart/day). No other significant food interactions. St. John's Wort may reduce contraceptive efficacy. |
| Clinical Pearls | This combination oral contraceptive (COC) contains 0.5 mg norgestrel (a progestin) and 50 mcg ethinyl estradiol (a high-estrogen dose). It is a monophasic 21-day regimen. Use for contraception; also FDA-approved for moderate acne vulgaris in women >=15 years. High estrogen dose increases thrombotic risk; avoid in smokers over 35, hypertension, migraine with aura, or history of VTE. Advise consistent intake time (daily, same time). Breakthrough bleeding may occur; rule out pregnancy if missed pills. Antiepileptics (e.g., phenytoin, carbamazepine) and rifampin reduce efficacy. |
| Patient Advice | Take one pill daily at the same time for 21 days, then 7 days off; withdrawal bleeding occurs during the 7-day break. · Use backup contraception (e.g., condoms) if you miss a pill, vomit within 2 hours of taking it, or have severe diarrhea. · This pill does not protect against HIV or other sexually transmitted infections. · Serious side effects: leg pain (DVT), chest pain (PE), severe headache (stroke), jaundice (liver disease); stop and call doctor immediately. · Do not smoke while taking this pill, especially if over 35; smoking greatly increases risk of blood clots. · Tell your doctor if you are breastfeeding, planning pregnancy, or have any medical conditions (e.g., hypertension, diabetes, migraine). · Grapefruit juice may increase estrogen levels; avoid excessive consumption. · Antibiotics (e.g., rifampin) and certain anticonvulsants can reduce effectiveness. |
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