Comparative Pharmacology
Head-to-head clinical analysis: LO LOESTRIN FE versus LO BLISOVI FE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: LO LOESTRIN FE versus LO BLISOVI FE.
LO LOESTRIN FE vs LO-BLISOVI FE
Head-to-head clinical comparison of therapeutic indices and safety profiles.
Combination of ethinyl estradiol and norethindrone acetate suppresses gonadotropin-releasing hormone (GnRH) from the hypothalamus, reducing luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary, thereby inhibiting ovulation. The progestin component thickens cervical mucus, impeding sperm penetration, and alters endometrial receptivity. Ferrous fumarate provides supplemental iron.
Combination hormonal contraceptive: ethinyl estradiol suppresses gonadotropin release, inhibiting ovulation; norethindrone induces endometrial changes, increasing cervical mucus viscosity.
Oral contraceptionTreatment of heavy menstrual bleeding (off-label)Dysmenorrhea (off-label)Acne vulgaris (off-label)Polycystic ovary syndrome (off-label)
Prevention of pregnancyTreatment of heavy menstrual bleeding (off-label)Acne vulgaris (off-label)
One tablet orally once daily. Each tablet contains norethindrone acetate 1 mg and ethinyl estradiol 10 mcg (24 active tablets) followed by ferrous fumarate 75 mg (2 inactive tablets).
One tablet orally once daily for 21 consecutive days, followed by 7 days of placebo tablets.
None Documented
None Documented
Norethindrone: ~8 hours (range 5–12 h); Ethinyl estradiol: ~14 hours (range 10–20 h). Terminal half-life supports once-daily dosing with steady-state reached within 7–14 days.
Terminal elimination half-life: 15-18 hours for ethinyl estradiol; clinical context: supports once-daily dosing
Ethinyl estradiol is metabolized primarily via CYP3A4, with hydroxylation and conjugation pathways. Norethindrone acetate is rapidly hydrolyzed to norethindrone, which is metabolized via reduction and conjugation. Ferrous fumarate is absorbed and utilized for hemoglobin synthesis.
Hepatic via CYP3A4 (ethinyl estradiol) and primarily conjugation (norethindrone); first-pass metabolism.
Renal (primarily as glucuronide conjugates of norethindrone and ethinyl estradiol): ~40% norethindrone metabolites, ~30% ethinyl estradiol metabolites; Fecal: ~30% norethindrone metabolites, ~40% ethinyl estradiol metabolites.
Renal (approximately 60% as metabolites, 10-15% as unchanged drug); fecal (about 20-30%)
Norethindrone: ~61% bound (primarily to albumin and SHBG); Ethinyl estradiol: ~97–98% bound (primarily to albumin, with ~1–2% free).
Ethinyl estradiol: 95-98% bound to albumin and sex hormone-binding globulin (SHBG)
Norethindrone: ~4 L/kg; Ethinyl estradiol: ~3–4 L/kg. Indicates extensive tissue distribution consistent with lipophilic steroids.
Ethinyl estradiol: 2-5 L/kg; indicates extensive tissue distribution
Norethindrone: ~64% (oral); Ethinyl estradiol: ~45% (oral) due to first-pass metabolism, with high interindividual variability.
Oral: ethinyl estradiol approximately 40-50% (first-pass metabolism)
No specific dosage adjustment required for renal impairment. Use with caution in patients with renal dysfunction due to potential fluid retention.
No dose adjustment required in renal impairment. Use with caution if severe renal impairment or nephrotic syndrome due to potential fluid retention.
Contraindicated in patients with hepatic impairment, including acute or chronic liver disease, hepatic adenomas, or impaired liver function. No adjustment guidelines available; do not use.
Contraindicated in acute hepatic disease or severe cirrhosis (Child-Pugh class C). Not recommended in moderate impairment (Child-Pugh B) without specialist advice. No data for mild (Child-Pugh A); use caution.
Not indicated for use before menarche. For post-menarchal adolescents, same dosing as adults: one tablet orally once daily.
Not indicated in pediatric patients before menarche. For postmenarchal females, same adult dose may be used; weight-based dosing not established.
Not indicated for use in postmenopausal women. No specific dosing adjustments for elderly patients as the drug is not used in this population.
Not indicated in postmenopausal women. No specific geriatric dose adjustments; consider increased risk of thrombotic events and comorbidities.
Cigarette smoking increases the risk of serious cardiovascular events from combination oral contraceptives. 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 COC use. Risk increases with age and heavy smoking (≥15 cigarettes/day). Women over 35 who smoke should not use COCs.
["Increased risk of venous thromboembolism (VTE), myocardial infarction, and stroke, especially in smokers and women with hypertension or migraines","Adverse effects on bone density and potential for fractures with long-term use","Hepatic adenoma or hepatocellular carcinoma risk","Gallbladder disease","Glucose intolerance and insulin resistance","Elevated blood pressure","Cholestatic jaundice","Ocular lesions (e.g., retinal thrombosis)","Depression","Iron overload in patients with hemochromatosis or chronic hemolytic anemia (due to ferrous fumarate)"]
["Thrombotic disorders (DVT, PE, stroke, MI)","Carcinoma (breast, cervical, liver)","Hepatic disease (jaundice, cholestasis)","Hypertension","Carbohydrate/lipid effects","Headache/migraine","Bleeding irregularities","Drug interactions (CYP3A4 inducers/inhibitors)","Depression","Gallbladder disease","Hereditary angioedema"]
["Current or history of thrombophlebitis, DVT, or thromboembolic disorders","Cerebrovascular or coronary artery disease","Known or suspected pregnancy","Undiagnosed abnormal uterine bleeding","Breast carcinoma or other hormone-sensitive cancer","Hepatic tumor (benign or malignant) or active liver disease","Hypersensitivity to any component","Smoking in women over 35","Hemochromatosis or chronic hemolytic anemia (due to ferrous fumarate)"]
["Venous or arterial thrombotic/thromboembolic events (current or history)","Cerebrovascular or coronary artery disease","Valvular heart disease with complications","Uncontrolled hypertension","Major surgery with prolonged immobilization","Diabetes with vascular involvement","Headache with focal neurological symptoms or migraine with aura (age ≥35)","Current or history of breast cancer or other estrogen-sensitive neoplasia","Hepatic adenomas or malignant liver tumors","Acute or chronic liver disease with abnormal function","Undiagnosed abnormal uterine bleeding","Known or suspected pregnancy","Cigarette smoking in women >35 years","Hypersensitivity to any component"]
Data Pending Review
Data Pending Review
No specific food interactions are known for Lo Loestrin Fe. However, grapefruit juice may increase ethinyl estradiol levels, potentially increasing side effects; it is prudent to advise against excessive grapefruit juice consumption. Iron tablets should be taken with food to reduce gastrointestinal upset; calcium-rich foods or supplements may decrease iron absorption, so separate iron intake from high-calcium meals by at least 2 hours.
Grapefruit juice may increase estrogen levels and risk of adverse effects; avoid large quantities. Iron absorption is enhanced by vitamin C (e.g., orange juice) and inhibited by tannins (tea, coffee), calcium (dairy), and phytates (whole grains); separate iron intake from these foods by at least 2 hours. Take with food to reduce GI upset.
Pregnancy category X. Contraindicated in pregnant women due to risk of fetal harm, including cardiovascular defects and neural tube defects. Use during first trimester associated with oral clefts; second and third trimester use may lead to fetal hyperbilirubinemia and jaundice.
Pregnancy category X. Combination hormonal contraceptives are contraindicated in pregnancy due to known risks to the fetus, including cardiovascular and limb defects from first-trimester exposure, and potential feminization of male fetuses from progestin exposure. Post-conception use is not indicated; if exposure occurs, evaluate for pregnancy.
Excreted in breast milk in small amounts; no reported adverse effects in infants. M/P ratio for ethinyl estradiol is approximately 0.04. Use with caution, especially during early postpartum period due to potential effects on milk production.
Small amounts of progestins and estrogens are excreted in breast milk; M/P ratio not established for this specific formulation. Use in breastfeeding women is generally not recommended due to potential effects on milk production and composition, and possible long-term effects on the infant. Alternative contraception methods are advised until weaning.
Not applicable; drug is contraindicated in pregnancy. No dose adjustments recommended due to absence of safe therapeutic use.
Contraindicated in pregnancy. If pregnancy occurs, discontinue immediately. No dose adjustment is applicable as the drug should not be used in pregnancy. Pharmacokinetic changes in pregnancy (increased clearance) are irrelevant due to contraindication.
Category C
Category C
Lo Loestrin Fe contains norethindrone acetate and ethinyl estradiol (1 mg/10 mcg) as the active hormonal pills, with a low iron (75 mg ferrous fumarate) supplement during the placebo week. It is the lowest-dose combination oral contraceptive available, which may minimize estrogen-related side effects. The regimen is 24 active pills, 2 placebo pills, then 2 iron pills, for a 28-day cycle. Spotting and breakthrough bleeding are common, especially in the first few cycles. It is indicated for contraception and not for emergency contraception. The iron tablets do not replace iron deficiency treatment. Contraindicated in patients with a history of thromboembolic disorders, liver disease, or known/suspected pregnancy.
LO-BLISOVI FE (norethindrone acetate/ethinyl estradiol/ferrous fumarate) is a combined oral contraceptive with iron supplementation. The iron component (75 mg ferrous fumarate) compensates for menstrual blood loss. Administer at the same time daily to maintain stable hormone levels. Missed doses increase risk of breakthrough bleeding and contraceptive failure. Consider non-oral contraceptives in patients with malabsorption or vomiting.
Take one pill daily at the same time each day, preferably after the evening meal.The first 24 pills are light blue (hormonal), the next 2 are white (placebo), and the last 2 are brown (iron tablets).If you miss a dose: take it as soon as remembered, and if more than 12 hours late, use backup contraception for 7 days.Common side effects: spotting, nausea, breast tenderness, and mood changes; these often improve after 3 months.If you experience severe abdominal or chest pain, headache, or vision changes, seek medical attention.Iron pills do not treat anemia; they only supplement daily iron needs.Report any jaundice, depression, or high blood pressure to your healthcare provider.Use an additional non-hormonal method if starting for the first time after the 5th day of your period.
Take one tablet daily at the same time with food to reduce nausea.Missed doses: if one dose is missed >12 hours, take it immediately and continue; if two doses are missed, take two tablets and use backup contraception for 7 days.Iron tablets may cause dark stools; this is harmless.Report severe headache, chest pain, leg swelling, or vision changes immediately.Do not smoke while taking this medication; smoking increases risk of blood clots.Store in original blister pack; do not remove desiccant.