What is the equivalent medication to Lo Loestrin Fe (ethinyl estradiol and norethindrone acetate) in terms of doses of estrogen and progesterone?

Equivalent Medications to Lo Loestrin Fe

The closest equivalent to Lo Loestrin Fe (norethindrone acetate 1 mg/ethinyl estradiol 10 mcg) is Loestrin 1/20 (norethindrone acetate 1 mg/ethinyl estradiol 20 mcg), which contains the same progestin dose but double the estrogen dose. 1

Understanding Lo Loestrin Fe Composition

Lo Loestrin Fe is an ultra-low-dose combined oral contraceptive containing:

• Norethindrone acetate: 1 mg
• Ethinyl estradiol: 10 mcg (the lowest estrogen dose available in any FDA-approved COC)
• 24-day active hormone regimen with 2 days of estrogen-only pills and 2 days of ferrous fumarate 1

Direct Equivalents

Exact Match Options

No other formulation contains exactly 10 mcg of ethinyl estradiol combined with norethindrone acetate. Lo Loestrin Fe is unique in having the lowest estrogen dose on the market. 2

Closest Alternatives by Hormone Content

Loestrin 1/20 (norethindrone acetate 1 mg/ethinyl estradiol 20 mcg):

• Same progestin type and dose
• Double the estrogen (20 mcg vs 10 mcg)
• Available in both 21-day and 24-day (Loestrin 24 Fe) formulations
• The 24-day version provides better cycle control with fewer breakthrough bleeding days compared to 21-day regimens 1

Loestrin Fe 1.5/30 (norethindrone acetate 1.5 mg/ethinyl estradiol 30 mcg):

• Higher doses of both components
• 50% more progestin and triple the estrogen
• May provide better contraceptive efficacy but higher hormone exposure 2

Alternative Low-Dose Formulations with Different Progestins

If switching progestin types is acceptable:

Ortho Tri-Cyclen Lo (norgestimate 180/215/250 mcg/ethinyl estradiol 25 mcg):

• Triphasic formulation with 25 mcg ethinyl estradiol
• Second-generation progestin with antiandrogenic properties
• Excellent cycle control and high satisfaction rates 3
• FDA-approved for acne treatment 4

Yaz (drospirenone 3 mg/ethinyl estradiol 20 mcg):

• 20 mcg ethinyl estradiol (double Lo Loestrin Fe)
• Fourth-generation progestin with antiandrogenic and antimineralocorticoid properties
• 24/4 day regimen similar to Lo Loestrin Fe
• FDA-approved for acne treatment 2, 4

Important Clinical Considerations

Estrogen Dose Implications

• Lo Loestrin Fe's 10 mcg estrogen dose is at the extreme low end of the spectrum 2
• Historically, estrogen doses have decreased from 150 mcg to current ranges of 10-50 mcg 2
• Lower estrogen doses may increase breakthrough bleeding risk but potentially reduce thrombotic risk 2

Progestin Considerations

Norethindrone acetate has unique metabolic properties:

• Converts to ethinyl estradiol in vivo at approximately 4-6 mcg per mg of norethindrone acetate 5
• This means 1 mg norethindrone acetate may produce an additional 4-6 mcg of ethinyl estradiol systemically
• First-generation progestin with moderate androgenic activity when used alone 2
• When combined with estrogen, net effect is antiandrogenic 2

Switching Considerations

When transitioning from Lo Loestrin Fe:

• Loestrin 1/20 or Loestrin 24 Fe provide the most similar hormonal profile 1
• The 24-day regimen (Loestrin 24 Fe) offers significantly fewer breakthrough bleeding days (18.6 vs 23.2 days over cycles 2-6) compared to 21-day formulations 1
• Patients may experience changes in bleeding patterns, particularly with higher estrogen doses 3
• Consider cardiovascular risk factors when selecting estrogen dose, though absolute VTE risk remains low (3-9 per 10,000 woman-years for standard COCs) 2

Contraindications Apply to All Formulations

All combined oral contraceptives share similar contraindications including:

• History of venous thromboembolism
• Uncontrolled hypertension
• Smoking in women over 35 years
• Migraine with aura
• Active liver disease
• Estrogen-sensitive cancers 2, 4