Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
PORTIA-28 vs ALTAVERA
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Combination oral contraceptive: estrogen (ethinyl estradiol) suppresses gonadotropin release, inhibiting ovulation; progestin (levonorgestrel) alters cervical mucus and endometrial lining.
Combination of ethinyl estradiol and desogestrel: ethinyl estradiol suppresses gonadotropin release, inhibiting ovulation; desogestrel (progestin) causes cervical mucus thickening and endometrial atrophy, preventing implantation.
Prevention of pregnancy
Prevention of pregnancy,Treatment of moderate acne vulgaris (in females ≥15 years with no contraindications)
One tablet (levonorgestrel 0.15 mg, ethinyl estradiol 0.03 mg) orally once daily
1 tablet (ethinyl estradiol 0.03 mg / levonorgestrel 0.15 mg) orally once daily for 21 days, followed by 7 placebo days.
Levonorgestrel: 24-30 hours; ethinyl estradiol: 12-15 hours. Clinical context: Steady-state achieved within 5-7 days.
Levonorgestrel: terminal elimination half-life 25±10 hours; ethinyl estradiol: 13±7 hours. Clinical context: steady-state concentrations achieved within 5-7 days; contraceptive efficacy requires consistent daily dosing.
Hepatic: ethinyl estradiol and levonorgestrel are metabolized via CYP3A4, conjugation, and sulfation.
Ethinyl estradiol: primarily metabolized by CYP3A4; undergoes sulfation and glucuronidation. Desogestrel: rapidly converted to active metabolite etonogestrel via CYP2C9 and CYP2C19; further metabolism by CYP3A4.
Renal (60-70% as metabolites, 20-30% as levonorgestrel/ethinyl estradiol glucuronides), fecal (10-20%), biliary (minor).
Renal excretion of metabolites and unchanged drug: ~30% (levonorgestrel) and ~20% (ethinyl estradiol) in urine; biliary/fecal elimination: ~40-50% as conjugates and metabolites.
Levonorgestrel: 97.5-99% to sex hormone-binding globulin (SHBG) and albumin; ethinyl estradiol: 98-99% to albumin.
Levonorgestrel: 98-99% bound to sex hormone-binding globulin (SHBG) and albumin; ethinyl estradiol: 98% bound to albumin.
Levonorgestrel: 1.8 L/kg (extensive tissue distribution).
Levonorgestrel: Vd ~1.8 L/kg (suggesting extensive tissue distribution). Ethinyl estradiol: Vd ~2.4 L/kg.
Oral: levonorgestrel ~100%, ethinyl estradiol ~40-45% (first-pass metabolism).
Oral bioavailability: levonorgestrel ~100% (nearly complete); ethinyl estradiol ~45-50% (first-pass hepatic metabolism).
No dose adjustment required for mild to moderate renal impairment; contraindicated in severe renal disease
No dose adjustment required for mild to moderate renal impairment. Contraindicated in severe renal disease or acute renal failure due to potential fluid retention.
Contraindicated in acute hepatic disease or severe cirrhosis (Child-Pugh C); use with caution in mild to moderate hepatic impairment
Contraindicated in severe hepatic dysfunction (Child-Pugh class B or C). Use caution in mild to moderate impairment (Child-Pugh A); monitor liver enzymes.
Use only after menarche; dose as per adult schedule (one tablet daily)
Not indicated for use before menarche. For postmenarchal adolescents, same dosing as adults (1 tablet daily, 21/7 regimen) after evaluation of risks.
Not indicated for postmenopausal women
Not indicated for postmenopausal women. No specific geriatric dosing; consider increased risk of thromboembolism, cardiovascular disease, and metabolic effects in older women of reproductive age.
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.
Cigarette smoking increases risk of serious cardiovascular events from combined oral contraceptives. Risk increases with age (especially >35 years) and with number of cigarettes smoked. Women who use combined hormonal contraceptives should be strongly advised not to smoke.
Increased risk of thromboembolic disorders (VTE, MI, stroke),Hepatic neoplasia,Hypertension,Gallbladder disease,Carbohydrate/lipid metabolism effects,Bleeding irregularities
Thrombotic disorders: risk of venous thromboembolism (VTE), stroke, myocardial infarction; discontinue if thrombotic event occurs.,Hepatic disease: discontinue if jaundice or liver function abnormalities develop.,Hypertension: monitor blood pressure; discontinue if uncontrolled.,Carbohydrate metabolism: may affect glucose tolerance; monitor diabetic patients.,Depression: discontinue if significant depression occurs.,Gallbladder disease: increased risk of cholelithiasis.
Thrombophlebitis or thromboembolic disorders,Cerebrovascular or coronary artery disease,Known or suspected pregnancy,Undiagnosed abnormal genital bleeding,Known or suspected breast cancer,Liver tumors or active liver disease,Hypersensitivity to any component,Use with Hepatitis C drug combinations containing ombitasvir/paritaprevir/ritonavir with or without dasabuvir
Thrombophlebitis or thromboembolic disorders (current or history),Cerebrovascular or coronary artery disease (current or history),Known or suspected breast carcinoma,Estrogen-dependent neoplasia (known or suspected),Undiagnosed abnormal genital bleeding,Cholestatic jaundice of pregnancy or jaundice with prior pill use,Hepatic adenoma or carcinoma (known or suspected),Pregnancy (known or suspected),Hypersensitivity to any component
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.
No significant food interactions. Alcohol does not affect efficacy but may increase risk of adverse effects such as nausea. Grapefruit juice has no known interaction. Avoid excessive alcohol consumption due to potential hepatotoxicity.
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.
ALTAVERA contains ethinyl estradiol and levonorgestrel. First trimester: Inadvertent exposure during organogenesis is associated with a very low absolute risk of cardiovascular defects (relative risk 1.2-1.4) and no consistent increase in other major malformations. Second and third trimesters: No known teratogenic effects, but theoretical risks from estrogenic effects (e.g., feminization of male fetus). Postnatal: No increased risk of long-term developmental effects from pregnancy exposure.
Excreted into breast milk. M/P ratio not well established; progestins and estrogens are present in low levels. Potential for adverse effects on infant such as jaundice and breast enlargement. Generally not recommended during breastfeeding; alternative contraception advised.
Combined oral contraceptives may reduce milk production and quality, especially in early lactation. Ethinyl estradiol transfers into breast milk at low levels (M/P ratio approximately 0.1-0.2), excluding clinical effects in term infants. Levonorgestrel transfer is minimal (M/P ratio ~0.2-0.4). Use is generally avoided in breastfeeding women, especially during the first 6 weeks postpartum. Progestin-only methods are preferred.
Not applicable; contraindicated in pregnancy. No dose adjustment recommendations exist as use is contraindicated.
Contraindicated in pregnancy. No dose adjustment recommended because use is discontinued upon confirmed or suspected pregnancy. Pharmacokinetic changes in pregnancy (e.g., increased hepatic clearance, altered binding proteins) are not relevant for this indication.
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.
ALTAVERA is a combined oral contraceptive (COC) containing ethinylestradiol and levonorgestrel. It inhibits ovulation via suppression of gonadotropins. Counsel patients to take at the same time daily to maintain efficacy. Missed pill management: if missed within 12 hours, take immediately; if >12 hours, take last missed pill and use backup contraception for 7 days. Be aware of increased VTE risk, especially in smokers over 35. May reduce effectiveness of lamotrigine; monitor seizure control. Initiate on the first day of menses or first Sunday after onset.
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.
Take one tablet daily at the same time each day, with or without food.,If you miss a pill by less than 12 hours, take it as soon as you remember. If more than 12 hours, take the missed pill and use a backup method (e.g., condoms) for the next 7 days.,Smoking increases your risk of serious cardiovascular side effects, especially if you are over 35 years old. Do not smoke while taking this medication.,Seek immediate medical attention if you experience sudden severe headache, chest pain, leg pain/swelling, or vision changes (symptoms of blood clots).,This medication does not protect against HIV or other sexually transmitted infections.,If you are taking lamotrigine or other anticonvulsants, tell your doctor; your seizure medication may be less effective.,Store at room temperature away from moisture and heat.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about PORTIA-28 vs ALTAVERA, answered by our medical review team.
PORTIA-28 is a Oral Contraceptive that works by Combination oral contraceptive: estrogen (ethinyl estradiol) suppresses gonadotropin release, inhibiting ovulation; progestin (levonorgestrel) alters cervical mucus and endometrial lining.. ALTAVERA is a Combined Oral Contraceptive that works by Combination of ethinyl estradiol and desogestrel: ethinyl estradiol suppresses gonadotropin release, inhibiting ovulation; desogestrel (progestin) causes cervical mucus thickening and endometrial atrophy, preventing implantation.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between PORTIA-28 and ALTAVERA depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of PORTIA-28 is: One tablet (levonorgestrel 0.15 mg, ethinyl estradiol 0.03 mg) orally once daily. The standard adult dose of ALTAVERA is: 1 tablet (ethinyl estradiol 0.03 mg / levonorgestrel 0.15 mg) orally once daily for 21 days, followed by 7 placebo days.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between PORTIA-28 and ALTAVERA in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. PORTIA-28 is classified as Category C. Pregnancy category X. Contraindicated in pregnancy. First trimester exposure associated with cardiovascular defects, neural tube defects, and limb reduction anomalies. Second and t. ALTAVERA is classified as Category C. ALTAVERA contains ethinyl estradiol and levonorgestrel. First trimester: Inadvertent exposure during organogenesis is associated with a very low absolute risk of cardiovascular def. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.