PORTIA-21
Clinical safety rating
cautionComprehensive clinical and safety monograph for PORTIA-21 (PORTIA-21).
Oral contraceptive: inhibition of ovulation by suppressing gonadotropin release; increases viscosity of cervical mucus, reducing sperm penetration; alters endometrial receptivity.
| Metabolism | Ethinyl estradiol undergoes first-pass metabolism in liver and gut via CYP3A4; levonorgestrel metabolized via CYP3A4 and reduction/sulfation. |
| Excretion | Renal (50-60% unchanged), fecal (30-40% as metabolites), minor biliary |
| Half-life | Terminal elimination half-life: 24-30 hours; clinical context: steady-state reached after 5-7 days, allows once-daily dosing |
| Protein binding | 98-99% bound, primarily to albumin and sex hormone-binding globulin (SHBG) |
| Volume of Distribution | 2.8-4.1 L/kg, indicating extensive tissue distribution and accumulation in fat and reproductive organs |
| Bioavailability | Oral: 60-80% (first-pass metabolism reduces systemic availability); IV: 100% |
| Onset of Action | Oral: 1-2 hours for detectable serum levels; 4-6 hours for peak effect; IV: within minutes for therapeutic effect |
| Duration of Action | Oral: 24 hours (supports once-daily dosing); IV: 6-12 hours depending on dose and indication |
| Molecular Weight | Ethinyl estradiol: 296.4 Da; Levonorgestrel: 312.4 Da |
| Action Class | Combination oral contraceptive (estrogen-progestin) |
One tablet (norgestimate 0.180 mg/ethinyl estradiol 0.035 mg) orally once daily for 21 days, followed by 7 days of placebo.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment. Insufficient data for severe renal impairment (eGFR <30 mL/min/1.73 m²); use with caution. |
| Liver impairment | Contraindicated in Child-Pugh class B or C (moderate to severe hepatic impairment). For Child-Pugh class A, use with caution; no specific dose adjustment recommended. |
| Pediatric use | Not indicated for use before menarche. Post-menarche: same as adult dosing (one tablet daily for 21 days, then 7 days placebo). |
| Geriatric use | Not indicated for postmenopausal women. No specific geriatric dosing recommendations; follow standard dosing if prescribed off-label, but consider increased risk of thromboembolism and cardiovascular events. |
| 1st trimester | Contains ethinyl estradiol and levonorgestrel; risk of birth defects (e.g., cardiovascular, limb defects) based on observational studies. Use only if benefit outweighs risk. |
| 2nd trimester | Risk of adverse effects such as cholestasis, jaundice, and potential hepatic adenoma. Use only if clearly needed. |
| 3rd trimester | May cause premature closure of ductus arteriosus and pulmonary hypertension in neonate due to estrogenic effects. Avoid during last trimester. |
Clinical note
Comprehensive clinical and safety monograph for PORTIA-21 (PORTIA-21).
| Placental transfer | Both ethinyl estradiol and levonorgestrel cross the placenta; transfer is moderate to high with accumulation in fetal tissues. |
| Breastfeeding | Excreted into breast milk in small amounts; may reduce milk production and affect infant (e.g., jaundice, breast enlargement). Consider alternative contraception. |
| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | Pregnancy category X. Contraindicated in pregnancy. First trimester: Major congenital anomalies including cardiovascular, skeletal, and neural tube defects due to progestin and estrogen exposure. Second and third trimesters: Increased risk of fetal genital abnormalities, urogenital malformations, and potential long-term effects on reproductive development. Use only if pregnancy is ruled out. |
| Fetal Monitoring | Maternal: Regular pregnancy testing, liver function tests, blood pressure monitoring, lipid profile, glucose tolerance test. Fetal: Ultrasound for anatomical survey and growth assessment if inadvertent exposure occurs. Monitor for signs of fetal distress if pregnancy continues. |
| Fertility Effects | Returns fertility rapidly upon discontinuation. No known long-term impairment. May initially cause menstrual irregularities post-discontinuation but no permanent effects on ovulatory function, implantation, or subsequent fertility. |
■ FDA Black Box Warning
Cigarette smoking increases risk of serious cardiovascular events from combination hormonal contraceptives. Risk increases with age (especially >35) and number of cigarettes smoked. Women >35 who smoke should not use this product.
| Common Effects | Nausea, Headache, Breast tenderness, Weight changes, Irregular menstrual bleeding, Mood changes |
| Serious Effects | Venous thromboembolism (deep vein thrombosis, pulmonary embolism), Arterial thromboembolism (myocardial infarction, stroke), Hepatic adenoma or hepatocellular carcinoma, Hypertension, Gallbladder disease, Cerebrovascular accident |
Thrombophlebitis or thromboembolic disordersHistory of deep vein thrombosis or pulmonary embolismCerebrovascular or coronary artery diseaseKnown or suspected pregnancyUndiagnosed abnormal genital bleedingKnown or suspected carcinoma of the breastEstrogen-dependent neoplasiaBenign or malignant liver tumor (active or history)Active liver disease (e.g., hepatitis, cirrhosis)Hypersensitivity to any component
| Precautions | Increased risk of thromboembolic disorders, Elevated blood pressure, Hepatic neoplasia or active liver disease, Gallbladder disease, Carbohydrate/lipid effects, Ocular changes (retinal thrombosis), Headache/migraine, Menstrual irregularities |
| Food/Dietary | No specific food interactions are known. Grapefruit juice may increase estrogen levels but not clinically significant; no dietary restrictions required. Take with food or milk if nausea occurs. |
| Clinical Pearls | Portia-21 (oral contraceptive pill containing levonorgestrel and ethinyl estradiol) requires strict adherence to a daily schedule; missed pills increase ovulation risk. First dose should be taken on the first day of menstruation for immediate contraceptive effect. Counsel patients that breakthrough bleeding is common in initial cycles but usually resolves. Concomitant use with CYP3A4 inducers (e.g., rifampin, St. John's wort) reduces efficacy and requires alternative contraception. Monitor blood pressure and consider increased thrombotic risk in smokers over age 35. |
| Patient Advice | Take one pill at the same time every day, even if you do not have sex that day. · If you miss a pill, refer to the package insert instructions; use backup contraception for 7 days if late by more than 12 hours. · Breakthrough spotting or nausea may occur initially but often improves; do not stop taking the pill. · Tell your doctor about all medications, including over-the-counter drugs and herbal supplements. · Smoking while taking this pill increases risk of blood clots, especially if over 35 years old. |
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