Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
PHILITH vs ALTAVERA
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
PHILITH is a combined oral contraceptive containing ethinyl estradiol and drospirenone. Ethinyl estradiol suppresses gonadotropin release, while drospirenone is a progestin with antiandrogenic and antimineralocorticoid activity, inhibiting ovulation and altering cervical mucus.
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,Treatment of moderate acne vulgaris in women at least 14 years old who have no known contraindications to oral contraceptive therapy and have achieved menarche,Treatment of premenstrual dysphoric disorder (PMDD) in women of reproductive age
Prevention of pregnancy,Treatment of moderate acne vulgaris (in females ≥15 years with no contraindications)
1 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.
Terminal half-life 12 hours; clinically relevant for twice-daily dosing with steady state reached after 2-3 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.
Ethinyl estradiol is metabolized primarily by CYP3A4, with sulfation and glucuronidation; drospirenone is metabolized by CYP3A4.
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: 90% unchanged; biliary/fecal: 10% as metabolites.
Renal excretion of metabolites and unchanged drug: ~30% (levonorgestrel) and ~20% (ethinyl estradiol) in urine; biliary/fecal elimination: ~40-50% as conjugates and metabolites.
98% bound to albumin.
Levonorgestrel: 98-99% bound to sex hormone-binding globulin (SHBG) and albumin; ethinyl estradiol: 98% bound to albumin.
0.3 L/kg; suggests limited extravascular distribution.
Levonorgestrel: Vd ~1.8 L/kg (suggesting extensive tissue distribution). Ethinyl estradiol: Vd ~2.4 L/kg.
Oral: 80% (high first-pass metabolism).
Oral bioavailability: levonorgestrel ~100% (nearly complete); ethinyl estradiol ~45-50% (first-pass hepatic metabolism).
GFR 30-89 m L/min: no adjustment; GFR 15-29 m L/min: 0.5 mg once daily; GFR <15 m L/min: not recommended
No dose adjustment required for mild to moderate renal impairment. Contraindicated in severe renal disease or acute renal failure due to potential fluid retention.
Child-Pugh A: no adjustment; Child-Pugh B: 0.5 mg once daily; Child-Pugh C: not recommended
Contraindicated in severe hepatic dysfunction (Child-Pugh class B or C). Use caution in mild to moderate impairment (Child-Pugh A); monitor liver enzymes.
Not approved for use in children under 18 years
Not indicated for use before menarche. For postmenarchal adolescents, same dosing as adults (1 tablet daily, 21/7 regimen) after evaluation of risks.
No specific adjustment; monitor renal function and adjust per renal guidelines
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 the risk of serious cardiovascular events from combination oral contraceptive use. This risk increases with age and with heavy smoking (15 or more cigarettes per day) and is quite marked in women over 35 years of age. Women who use combination oral contraceptives should be strongly advised not to smoke.
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 and thrombotic disorders (e.g., venous thromboembolism, stroke, myocardial infarction) especially in smokers over 35,Elevated blood pressure,Gallbladder disease,Carbohydrate and lipid metabolic effects,Hepatic neoplasia risk,Increased risk of pancreatitis due to hypertriglyceridemia,Chloasma (melasma) possibly persistent,Hereditary angioedema exacerbation in women with C1 esterase inhibitor deficiency,Impaired liver function
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.
Pregnancy,Current or history of thrombophlebitis or venous thromboembolic disorders,Cerebrovascular or coronary artery disease,Known or suspected breast carcinoma or other estrogen-dependent neoplasia,Undiagnosed abnormal genital bleeding,Hepatic adenoma or carcinoma,Jaundice or cholestatic jaundice of pregnancy or prior pill use,Known hypersensitivity to any component,Smoking over age 35,Uncontrolled hypertension,Diabetes with vascular involvement,Migraine with focal aura,Severe renal insufficiency or adrenal insufficiency (due to drospirenone's antimineralocorticoid effect)
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 estrogen levels, leading to increased side effects. St. John's Wort may decrease contraceptive effectiveness. Avoid excessive alcohol consumption as it may increase liver enzyme induction and reduce 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.
PHILITH is contraindicated in pregnancy. First trimester exposure carries high risk of neural tube defects, cardiac anomalies, and cleft palate based on animal studies and limited human data. Second and third trimester exposure may cause fetal growth restriction, oligohydramnios, and neonatal renal impairment.
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.
It is unknown whether PHILITH is excreted in human milk. Due to potential for serious adverse reactions in nursing infants, breastfeeding is not recommended during therapy and for 2 weeks after last dose. M/P ratio is not available.
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.
PHILITH is contraindicated in pregnancy; no dose adjustment can be recommended. Physiologic increases in renal clearance and hepatic metabolism during pregnancy may reduce drug exposure, but the teratogenic risk precludes use. If inadvertent exposure occurs, immediately discontinue and consider alternative therapy.
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.
PHILITH is a combination oral contraceptive containing ethinyl estradiol and progestin. Monitor for thromboembolic events; avoid in smokers over 35. Start on first day of menses or first Sunday after onset. Missed dose management: if missed >48 hours, use backup contraception for 7 days.
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 pill daily at same time; missed pills increase pregnancy risk.,Do not smoke while taking this medication; smoking increases risk of blood clots.,Use backup contraception (e.g., condoms) if you miss two or more pills.,Contact healthcare provider if you experience leg pain, chest pain, shortness of breath, or severe headache.,The medication does not protect against sexually transmitted infections.,You may have spotting or nausea initially; these usually improve.
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 PHILITH vs ALTAVERA, answered by our medical review team.
PHILITH is a Oral Contraceptive that works by PHILITH is a combined oral contraceptive containing ethinyl estradiol and drospirenone. Ethinyl estradiol suppresses gonadotropin release, while drospirenone is a progestin with antiandrogenic and antimineralocorticoid activity, inhibiting ovulation and altering cervical mucus.. 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 PHILITH 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 PHILITH is: 1 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 PHILITH 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. PHILITH is classified as Category C. PHILITH is contraindicated in pregnancy. First trimester exposure carries high risk of neural tube defects, cardiac anomalies, and cleft palate based on animal studies and limited . 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.