LO MINASTRIN FE

Clinical safety rating: caution

Comprehensive clinical and safety monograph for LO MINASTRIN FE (LO MINASTRIN FE).

How it works

Combination oral contraceptive containing ethinyl estradiol (estrogen) and norethindrone (progestin). Inhibits ovulation by suppressing gonadotropin release; increases viscosity of cervical mucus, inhibiting sperm penetration; alters endometrial lining, reducing implantation likelihood.

What the body does with it

Metabolism	Hepatic via CYP3A4 (ethinyl estradiol) and primarily reduction and conjugation (norethindrone); undergoes first-pass metabolism.
Excretion	Renal: 40-50% as conjugated metabolites; fecal: 20-30% via biliary excretion; unchanged drug <1%.
Half-life	Norethindrone: 8-11 hours; ethinyl estradiol: 12-16 hours. Steady-state achieved after 5-7 days of dosing.
Protein binding	Norethindrone: 97% bound (primarily to albumin and SHBG); ethinyl estradiol: 98% bound (primarily to albumin).
Volume of Distribution	Norethindrone: 4 L/kg; ethinyl estradiol: 2-4 L/kg; reflects extensive tissue distribution and binding to sex hormone receptors.
Bioavailability	Oral: norethindrone ~64%, ethinyl estradiol ~40-48% due to first-pass metabolism.
Onset of Action	Oral: contraceptive effect begins after 7 days of continuous dosing; requires 7 days of backup contraception if started after day 5 of menses.
Duration of Action	Oral: 24 hours; requires daily dosing to maintain contraceptive efficacy. Withdrawal bleed occurs during the 7-day placebo/iron period.

Classification & Brands

Dosing & administration

1 tablet (1 mg norethindrone acetate/20 mcg ethinyl estradiol/ferrous fumarate 75 mg) orally once daily for 28 consecutive days.

Dosage form	TABLET, CHEWABLE, TABLET
Renal impairment	No dose adjustment required for mild to moderate renal impairment (GFR ≥30 mL/min). Contraindicated in severe renal impairment (GFR <30 mL/min) or acute renal failure due to potential for hyperkalemia from ferrous fumarate.
Liver impairment	Contraindicated in Child-Pugh class B or C (moderate to severe hepatic impairment). For Child-Pugh class A, use caution; consider lower dose estrogen combination if necessary.
Pediatric use	Not indicated for use prepubertal. Approved for females of reproductive potential; safety and efficacy in children <12 years not established. Follow adult dosing postmenarche.
Geriatric use	Not indicated for use in postmenopausal women. In women >35 years who smoke, use is contraindicated due to increased cardiovascular risk.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for LO MINASTRIN FE (LO MINASTRIN FE).

Breastfeeding	Excreted in breast milk in small amounts (M/P ratio ~0.5). No adverse effects reported in infants, but may reduce milk production. Use with caution.
Teratogenic Risk	Pregnancy category X. Contraindicated in pregnancy due to risk of fetal harm. First trimester use associated with cardiovascular defects, neural tube defects; second/third trimester use associated with fetal genital changes, hepatic adenoma.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

Cigarette smoking increases risk of serious cardiovascular events from combination oral contraceptive use. Risk increases with age (>35 years) and with heavy smoking (≥15 cigarettes/day). Women >35 years who smoke should not use combination oral contraceptives.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Thrombophlebitis or thromboembolic disorders (current or history)","Cerebrovascular or coronary artery disease","Known or suspected breast carcinoma","Carcinoma of endometrium or other estrogen-dependent neoplasia","Undiagnosed abnormal genital bleeding","Cholestatic jaundice of pregnancy or jaundice with prior pill use","Hepatic adenoma or carcinoma","Known or suspected pregnancy","Hypersensitivity to any component","Heavy smoking (>15 cigarettes/day) in women >35 years"]

Clinical Precautions

Precautions

["Thrombotic disorders (thrombophlebitis, pulmonary embolism, cerebrovascular accidents, myocardial infarction)","Hepatic disease (benign/malignant tumors)","Hypertension","Gallbladder disease","Carbohydrate/lipid metabolism effects","Ocular changes (retinal thrombosis)","Headache/migraine","Uterine bleeding irregularities","Depression","Cervical cancer screening","Pregnancy test prior to initiation","Lactation (possible decreased milk production)"]

Clinical Tips & Counseling

Drug interactions

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LO MINASTRIN FE

Clinical safety rating: caution

Comprehensive clinical and safety monograph for LO MINASTRIN FE (LO MINASTRIN FE).

How it works

What the body does with it

Metabolism	Hepatic via CYP3A4 (ethinyl estradiol) and primarily reduction and conjugation (norethindrone); undergoes first-pass metabolism.
Excretion	Renal: 40-50% as conjugated metabolites; fecal: 20-30% via biliary excretion; unchanged drug <1%.
Half-life	Norethindrone: 8-11 hours; ethinyl estradiol: 12-16 hours. Steady-state achieved after 5-7 days of dosing.
Protein binding	Norethindrone: 97% bound (primarily to albumin and SHBG); ethinyl estradiol: 98% bound (primarily to albumin).
Volume of Distribution	Norethindrone: 4 L/kg; ethinyl estradiol: 2-4 L/kg; reflects extensive tissue distribution and binding to sex hormone receptors.
Bioavailability	Oral: norethindrone ~64%, ethinyl estradiol ~40-48% due to first-pass metabolism.
Onset of Action	Oral: contraceptive effect begins after 7 days of continuous dosing; requires 7 days of backup contraception if started after day 5 of menses.
Duration of Action	Oral: 24 hours; requires daily dosing to maintain contraceptive efficacy. Withdrawal bleed occurs during the 7-day placebo/iron period.

Classification & Brands

Dosing & administration

1 tablet (1 mg norethindrone acetate/20 mcg ethinyl estradiol/ferrous fumarate 75 mg) orally once daily for 28 consecutive days.

Dosage form	TABLET, CHEWABLE, TABLET
Renal impairment	No dose adjustment required for mild to moderate renal impairment (GFR ≥30 mL/min). Contraindicated in severe renal impairment (GFR <30 mL/min) or acute renal failure due to potential for hyperkalemia from ferrous fumarate.
Liver impairment	Contraindicated in Child-Pugh class B or C (moderate to severe hepatic impairment). For Child-Pugh class A, use caution; consider lower dose estrogen combination if necessary.
Pediatric use	Not indicated for use prepubertal. Approved for females of reproductive potential; safety and efficacy in children <12 years not established. Follow adult dosing postmenarche.
Geriatric use	Not indicated for use in postmenopausal women. In women >35 years who smoke, use is contraindicated due to increased cardiovascular risk.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for LO MINASTRIN FE (LO MINASTRIN FE).

Breastfeeding	Excreted in breast milk in small amounts (M/P ratio ~0.5). No adverse effects reported in infants, but may reduce milk production. Use with caution.
Teratogenic Risk	Pregnancy category X. Contraindicated in pregnancy due to risk of fetal harm. First trimester use associated with cardiovascular defects, neural tube defects; second/third trimester use associated with fetal genital changes, hepatic adenoma.
Fetal Monitoring