PORTIA-28
Clinical safety rating
cautionComprehensive clinical and safety monograph for PORTIA-28 (PORTIA-28).
Combination oral contraceptive: estrogen (ethinyl estradiol) suppresses gonadotropin release, inhibiting ovulation; progestin (levonorgestrel) alters cervical mucus and endometrial lining.
| Metabolism | Hepatic: ethinyl estradiol and levonorgestrel are metabolized via CYP3A4, conjugation, and sulfation. |
| Excretion | Renal (60-70% as metabolites, 20-30% as levonorgestrel/ethinyl estradiol glucuronides), fecal (10-20%), biliary (minor). |
| Half-life | Levonorgestrel: 24-30 hours; ethinyl estradiol: 12-15 hours. Clinical context: Steady-state achieved within 5-7 days. |
| Protein binding | Levonorgestrel: 97.5-99% to sex hormone-binding globulin (SHBG) and albumin; ethinyl estradiol: 98-99% to albumin. |
| Volume of Distribution | Levonorgestrel: 1.8 L/kg (extensive tissue distribution). |
| Bioavailability | Oral: levonorgestrel ~100%, ethinyl estradiol ~40-45% (first-pass metabolism). |
| Onset of Action | Oral: 7 days of continuous dosing required for contraceptive effect. |
| Duration of Action | Oral: 24 hours; requires daily dosing. Missed dose reduces contraceptive efficacy. |
| Molecular Weight | 312.4 Da (norethindrone); 362.5 Da (ethinyl estradiol) |
| Action Class | Combined hormonal contraceptive (estrogen-progestin combination) |
One tablet (levonorgestrel 0.15 mg, ethinyl estradiol 0.03 mg) orally once daily
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment; contraindicated in severe renal disease |
| Liver impairment | Contraindicated in acute hepatic disease or severe cirrhosis (Child-Pugh C); use with caution in mild to moderate hepatic impairment |
| Pediatric use | Use only after menarche; dose as per adult schedule (one tablet daily) |
| Geriatric use | Not indicated for postmenopausal women |
| 1st trimester | Unopposed estrogen exposure may increase risk of fetal congenital anomalies; avoid use during first trimester. |
| 2nd trimester | Associated with fetal harm; do not use as pregnancy test or for threatened abortion. |
| 3rd trimester | Use may cause withdrawal bleeding in newborn; avoid use in late pregnancy. |
Clinical note
Comprehensive clinical and safety monograph for PORTIA-28 (PORTIA-28).
| Placental transfer | Extensively crosses placenta; fetal serum concentrations approximate maternal levels. |
| Breastfeeding | Excreted in breast milk; may reduce milk production and composition; use only if clearly needed and with caution. |
| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | Pregnancy category X. Contraindicated in pregnancy. First trimester exposure associated with cardiovascular defects, neural tube defects, and limb reduction anomalies. Second and third trimester exposure may cause fetal adrenal suppression, virilization of female fetuses due to progestin component, and potential long-term neurodevelopmental effects. Postnatal effects include possible behavioral issues. |
| Fetal Monitoring | Monitor pregnancy test before initiation and monthly during use. If pregnancy suspected, discontinue immediately and refer for ultrasound. Monitor for signs of thromboembolism, hypertension, and hepatic dysfunction. Fetal monitoring includes anatomical ultrasound if exposure occurs. |
| Fertility Effects | May delay return to fertility after discontinuation. No permanent effect on fertility. Normal reproductive function typically resumes upon cessation. |
■ FDA Black Box Warning
Cigarette smoking increases risk of serious cardiovascular events from combination oral contraceptive use. Risk increases with age and heavy smoking (≥15 cigarettes/day). Women over 35 who smoke should not use this product.
| Common Effects | Nausea, Headache, Breast tenderness, Breakthrough bleeding or spotting, Weight gain, Mood changes (depression, irritability), Decreased libido |
| Serious Effects | Venous thromboembolism (deep vein thrombosis, pulmonary embolism), Arterial thromboembolism (myocardial infarction, stroke), Hepatic adenoma or hepatocellular carcinoma, Hypertension, Gallbladder disease, Thrombotic thrombocytopenic purpura (TTP) in patients with factor V Leiden mutation |
Known or suspected pregnancyUndiagnosed abnormal genital bleedingKnown or suspected breast cancerActive deep vein thrombosis or pulmonary embolismCurrent or history of thrombophilic disordersHepatic adenoma or carcinomaAcute or chronic liver disease with abnormal liver function
| Precautions | Increased risk of thromboembolic disorders (VTE, MI, stroke), Hepatic neoplasia, Hypertension, Gallbladder disease, Carbohydrate/lipid metabolism effects, Bleeding irregularities |
| Food/Dietary | Grapefruit and grapefruit juice may increase ethinyl estradiol levels and risk of adverse effects; avoid concurrent consumption. No other significant food interactions. Maintain consistent dietary habits as changes in diet may affect drug absorption. Do not consume alcohol excessively as it may increase risk of liver toxicity and reduce contraceptive efficacy. |
| Clinical Pearls | Portia-28 is a combination oral contraceptive (COC) containing ethinyl estradiol and levonorgestrel. Initiate on the first day of menstrual bleeding or the first Sunday after onset; if starting after day 5, use backup contraception for 7 days. Missed pill management: if one pill is missed, take it as soon as remembered and continue regular schedule (may take two pills in one day); if two or more pills are missed, take the most recent missed pill, discard others, use backup contraception for 7 days, and consider emergency contraception if unprotected intercourse occurred. Maximum efficacy requires daily adherence at the same time. CYP3A4 inducers (e.g., rifampin, St. John's wort) may reduce contraceptive effectiveness; consider alternative non-hormonal methods during co-administration. Portia-28 may increase serum potassium; caution with potassium-sparing diuretics, ACE inhibitors, or ARBs. Discontinue if migraines with aura, unexplained visual loss, or signs of thromboembolism occur. Monitor blood pressure and liver function periodically. |
| Patient Advice | Take one tablet daily at the same time each day, with or without food. Do not skip doses. · If you miss a pill, refer to the missed pill instructions in the package insert; use backup contraception if needed. · Portia-28 does not protect against HIV or other sexually transmitted infections; use condoms for STI prevention. · Smoking increases risk of serious cardiovascular events; avoid smoking, especially if over age 35. · Contact your healthcare provider immediately if you experience chest pain, shortness of breath, leg swelling, severe headache, vision changes, or jaundice. · Inform your doctor of all medications you take, including over-the-counter drugs and herbal supplements. · Store at room temperature away from moisture and heat; keep out of reach of children. |
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