OVRAL-28
Clinical safety rating
cautionComprehensive clinical and safety monograph for OVRAL-28 (OVRAL-28).
Combination oral contraceptive: suppresses gonadotropin release via estrogen and progestin, inhibiting ovulation, thickening cervical mucus, and altering endometrial lining.
| Metabolism | Ethinyl estradiol: primarily hepatic via CYP3A4, undergoes first-pass metabolism; norgestrel: hepatic reduction and conjugation, partially via CYP3A4. |
| Excretion | Renal: ~40% as metabolites; fecal: ~60% via biliary excretion, primarily as glucuronide and sulfate conjugates. |
| Half-life | Ethinyl estradiol: terminal half-life 13-27 hours (mean ~17 hours); norgestrel: terminal half-life 11-45 hours (mean ~24 hours). Clinical context: steady-state reached within 5-7 days; accumulation minimal with daily dosing. |
| Protein binding | Ethinyl estradiol: 97-98% bound, primarily to albumin; norgestrel: 93-95% bound, primarily to sex hormone-binding globulin (SHBG) and albumin. |
| Volume of Distribution | Ethinyl estradiol: 2.5-4.0 L/kg; norgestrel: 2.0-3.5 L/kg. High Vd indicates extensive tissue distribution and binding. |
| Bioavailability | Oral: ethinyl estradiol ~40-50% (due to first-pass metabolism); norgestrel ~60-70% (variable due to presystemic metabolism). |
| Onset of Action | Oral: contraceptive effect requires 7 days of consistent dosing; ovulation suppression achieved within 3-7 days; endometrial changes occur within 5-7 days. |
| Duration of Action | Contraceptive protection persists for 24 hours with daily dosing; after discontinuation, ovulation resumes typically within 2-4 weeks, but may be delayed in some individuals. |
| Molecular Weight | Ethinyl estradiol: 296.4 Da; Norgestrel: 312.45 Da |
One tablet (norgestrel 0.3 mg, ethinyl estradiol 0.03 mg) orally once daily for 21 consecutive days, followed by 7 days of placebo.
| Dosage form | TABLET |
| Renal impairment | No dosage adjustment required for mild to moderate renal impairment. Insufficient data for severe renal impairment (CrCl <30 mL/min); use with caution due to potential fluid retention. |
| Liver impairment | Contraindicated in acute hepatitis, hepatic adenomas, or severe cirrhosis (Child-Pugh class C). For mild to moderate impairment (Child-Pugh A or B), consider alternative therapy; if used, monitor liver function closely and reduce dose if tolerated. |
| Pediatric use | Not indicated for use before menarche. For postmenarchal adolescents, same dosing as adults (one tablet daily). |
| Geriatric use | Not indicated for use after menopause. No specific dosing adjustments provided for elderly patients; consider increased risk of thromboembolic events and cardiovascular disease. |
| 1st trimester | Contraindicated; association with limb reduction defects and cardiovascular anomalies. Use only for postcoital contraception. |
| 2nd trimester | Contraindicated; may cause feminization of male fetus and other endocrine effects. |
| 3rd trimester | Contraindicated; increased risk of neonatal jaundice and potential estrogenic effects. |
Clinical note
Comprehensive clinical and safety monograph for OVRAL-28 (OVRAL-28).
| Placental transfer | Both ethinyl estradiol and norgestrel cross the placenta. Ethinyl estradiol transfer is limited due to high protein binding, while norgestrel achieves fetal concentrations approximately 50% of maternal levels. |
| Breastfeeding | Small amounts of ethinyl estradiol and norgestrel are excreted into breast milk. May reduce milk production and alter milk composition. Use non-hormonal alternatives if possible; if used, monitor infant for jaundice and growth. |
| Lactation Rating | L3 - Moderately Safe |
| Teratogenic Risk | Pregnancy category X. First trimester: risk of congenital malformations (neural tube defects, cardiovascular anomalies) and spontaneous abortion. Second and third trimesters: associated with fetal adrenal suppression, hepatic impairment, and potential for masculinization of female genitalia. |
| Fetal Monitoring | Pregnancy test before initiation; monitor for thrombotic events, hypertension, hepatic function, and signs of fetal distress if accidental exposure occurs. |
| Fertility Effects | Reversible inhibition of ovulation during use. No long-term impact on fertility after discontinuation; return to normal ovulatory cycles typically occurs within 1-3 months. |
■ FDA Black Box Warning
Cigarette smoking increases risk of serious cardiovascular events. Combination oral contraceptives are contraindicated in women over 35 who smoke.
| Common Effects | Nausea Headache Breast pain Irregular uterine bleeding |
| Serious Effects |
Current or history of thromboembolic disordersCerebrovascular or coronary artery diseaseKnown or suspected pregnancyUndiagnosed abnormal genital bleedingKnown or suspected breast cancerEstrogen-dependent neoplasiaHepatic adenoma or carcinomaActive liver disease with abnormal liver functionTobacco use in women over 35 years of age
| Precautions | Increased risk of thrombotic disorders (venous thromboembolism, stroke, MI), Elevated blood pressure, Gallbladder disease, Hepatic neoplasia, Glucose intolerance, Retinal thrombosis, Depression |
| Food/Dietary | No significant food interactions known; however, grapefruit juice may increase ethinyl estradiol exposure. High-fat meals may slightly reduce absorption but not clinically significant. Advise consistent intake with food to minimize gastrointestinal upset. |
| Clinical Pearls | Ovral-28 is a combination oral contraceptive containing norgestrel and ethinyl estradiol. It is dosed as 28-day regimen with 21 active pills and 7 placebo. Patients should be counseled about the risk of thromboembolism, especially if over 35 years old and smoking. Efficacy may be reduced with concurrent use of certain anticonvulsants (e.g., phenytoin, carbamazepine) and antibiotics (e.g., rifampin). Instruct patients to take at the same time daily to maintain consistent serum levels. Missed doses require backup contraception; refer to package insert for missed pill algorithm. |
| Patient Advice | Take one pill daily at the same time, preferably with a meal to reduce nausea. · Do not skip pills; if a pill is missed, follow the instructions in the patient information leaflet and use backup contraception as directed. · Smoking increases the risk of serious cardiovascular side effects, especially in women over 35. Avoid smoking while on this medication. · Use backup contraception (like condoms) when starting the pill and if you miss pills or take certain other medications. · Common side effects include nausea, headache, breast tenderness, and breakthrough bleeding, which often improve after 2-3 months. · Seek medical attention immediately if you experience symptoms of blood clots: sudden chest pain, shortness of breath, leg pain/swelling, or sudden severe headache. · This medication does not protect against HIV or other sexually transmitted infections. |
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