OGESTREL 0.5/50-28
Clinical safety rating
cautionComprehensive clinical and safety monograph for OGESTREL 0.5/50-28 (OGESTREL 0.5/50-28).
Combination estrogen-progestin contraceptive; suppresses gonadotropins (FSH, LH) via negative feedback on hypothalamic-pituitary axis, inhibiting ovulation; increases cervical mucus viscosity and alters endometrial development.
| Metabolism | Norgestrel and ethinyl estradiol are metabolized primarily via cytochrome P450 3A4 (CYP3A4) in the liver; undergo first-pass metabolism; ethinyl estradiol also undergoes conjugation (sulfation, glucuronidation). |
| Excretion | Renal: 50-60% as metabolites (glucuronide and sulfate conjugates of norgestrel and ethinyl estradiol); Fecal: 30-40% via biliary elimination; Unchanged drug: <1%. |
| Half-life | Norgestrel: ~45 hours (range 24-56 h) enabling once-daily dosing; Ethinyl estradiol: ~17 hours (range 10-27 h). |
| Protein binding | Norgestrel: ~97% bound to sex hormone-binding globulin (SHBG) and albumin; Ethinyl estradiol: ~98% bound to albumin, with 2% free (active). |
| Volume of Distribution | Norgestrel: ∼4 L/kg (range 3-5 L/kg), indicating extensive tissue distribution; Ethinyl estradiol: ∼2 L/kg (range 1.5-3 L/kg), reflecting distribution to reproductive tissues and liver. |
| Bioavailability | Oral: Norgestrel ~90-100% (high first-pass metabolism but minimal systemic loss); Ethinyl estradiol ~40-50% due to first-pass metabolism (conjugation in gut wall and liver). |
| Onset of Action | Oral: Contraceptive effect begins after 7 days of consecutive daily doses; suppression of ovulation occurs by day 7. |
| Duration of Action | Oral: Contraceptive protection persists for the 21-day active pill period and during the 7-day placebo interval if taken correctly; maximum duration of action is 24 hours per active pill. |
| Molecular Weight | 312.45 |
One tablet (norgestrel 0.5 mg/ethinyl estradiol 50 mcg) orally once daily for 28-day cycle.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment. Not recommended in severe renal impairment (CrCl <30 mL/min) or ESRD due to lack of safety data. |
| Liver impairment | Contraindicated in acute hepatic disease or Child-Pugh class B and C cirrhosis. For mild hepatic impairment (Child-Pugh A), use with caution; no specific dose adjustment studied. |
| Pediatric use | Not indicated for children; use only after menarche. Postmenarcheal adolescents: same as adult dosing (one tablet daily) once menses established. |
| Geriatric use | Not indicated for women ≥65 years; no geriatric-specific dosing recommended. Consider alternative therapies due to increased thrombosis risk and reduced bone density with prolonged use. |
| 1st trimester | Contraindicated; risk of teratogenicity (oral clefts, cardiac defects) from progestin and estrogen. Use during organogenesis should be avoided. |
| 2nd trimester | Contraindicated; may cause fetal harm. Considered a category X drug. Not indicated for use during pregnancy. |
| 3rd trimester | Contraindicated; may cause adverse effects on fetal development and genital abnormalities. Use only if clearly needed for a life-threatening condition. |
Clinical note
Comprehensive clinical and safety monograph for OGESTREL 0.5/50-28 (OGESTREL 0.5/50-28).
| Placental transfer | Both norgestrel and ethinyl estradiol cross the placenta; norgestrel shows significant transfer with fetal serum levels approximately 10-15% of maternal levels. |
| Breastfeeding | Excreted in breast milk; may decrease milk production and composition. Use is generally not recommended during breastfeeding due to potential adverse effects on the infant (e.g., jaundice, hormone disruption). |
| Lactation Rating | L5 (Contraindicated) |
| Teratogenic Risk | No increased risk of birth defects has been observed in clinical studies for norgestrel/ethinyl estradiol. Use during pregnancy is contraindicated as hormonal contraceptives are not indicated during gestation. There is no evidence of teratogenicity when inadvertently taken during early pregnancy. |
| Fetal Monitoring | Monitor for signs of thrombotic events (DVT, PE, stroke) and hypertension. In pregnancy, if exposure occurs, no specific fetal monitoring required beyond routine prenatal care. |
| Fertility Effects | Suppresses ovulation through inhibition of gonadotropins. After discontinuation, rapid return to normal fertility is expected. No long-term negative impact on fertility. |
■ FDA Black Box Warning
Cigarette smoking increases risk of serious cardiovascular events from combination oral contraceptives. Risk increases with age (>35 years) and number of cigarettes smoked. Women over 35 who smoke should not use this product.
| Serious Effects |
Current or history of thrombophlebitis or thromboembolic disordersCerebrovascular or coronary artery diseaseKnown or suspected breast carcinomaKnown or suspected estrogen-dependent neoplasiaUndiagnosed abnormal genital bleedingPregnancy or suspected pregnancyKnown hypersensitivity to any component
| Precautions | Thrombotic disorders (venous thromboembolism, arterial thromboembolism, stroke, MI), Cerebrovascular disease, Hepatic neoplasia, Gallbladder disease, Hypertension, Carbohydrate/lipid effects, Headache/migraine, Vaginal bleeding irregularities, Depression, Hereditary angioedema |
| Food/Dietary | No significant food interactions. Grapefruit juice may increase estrogen levels, but clinically negligible. Avoid high-fat meals if taking with a progestin-only pill (not applicable here). |
| Clinical Pearls | OGESTREL 0.5/50-28 contains norgestrel 0.5 mg and ethinyl estradiol 50 mcg. Its higher estrogen dose (50 mcg) increases thromboembolic risk; avoid in smokers over 35. Use as emergency contraception off-label. Missed pill management: if one pill missed, take as soon as remembered; if two or more missed, use backup contraception. Withdrawal bleeding typically occurs during the 7 placebo pills. |
| Patient Advice | Take one pill daily at the same time; do not skip doses. · During the 7 placebo pills, you will have a withdrawal bleed; this is normal. · Use backup contraception (e.g., condoms) if you miss 2 or more pills. · Do not smoke while taking this medication, especially if over age 35. · Report any signs of blood clots: leg pain/swelling, chest pain, shortness of breath, sudden headache or vision changes. · This medication does not protect against HIV or other sexually transmitted infections. |
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