LARIN 1.5/30

Clinical safety rating: caution

Comprehensive clinical and safety monograph for LARIN 1.5/30 (LARIN 1.5/30).

How it works

Combination oral contraceptive: ethinyl estradiol suppresses FSH and LH, preventing ovulation; norethindrone induces endometrial changes and increases cervical mucus viscosity, impeding sperm penetration.

What the body does with it

Metabolism	Ethinyl estradiol: primarily CYP3A4; norethindrone: primarily CYP3A4, with some reduction to active metabolites.
Excretion	Renal (40% as metabolites, <10% unchanged); fecal (50% as metabolites); biliary (minor).
Half-life	Ethinyl estradiol: 13-19 hours; Norethindrone: 7-9 hours. Steady-state achieved in ~5-7 days.
Protein binding	Ethinyl estradiol: 97-98% bound to albumin; Norethindrone: 93-99% bound to SHBG and albumin.
Volume of Distribution	Ethinyl estradiol: 2.5-5 L/kg; Norethindrone: 2-4 L/kg. Indicates extensive tissue distribution.
Bioavailability	Oral: Ethinyl estradiol ~40-50% (first-pass metabolism); Norethindrone ~50-60% (first-pass metabolism).
Onset of Action	Oral: contraceptive effect requires 7 days of continuous dosing; immediate if started on day 1 of menses.
Duration of Action	24 hours for contraceptive efficacy; requires daily dosing for sustained effect.

Classification & Brands

Dosing & administration

One tablet (norethindrone acetate 1.5 mg, ethinyl estradiol 30 mcg) orally once daily at the same time each day for 21 consecutive days, followed by 7 days of placebo tablets.

Dosage form	TABLET
Renal impairment	No dose adjustment required in mild to moderate renal impairment (CrCl >=30 mL/min). Use contraindicated in severe renal impairment (CrCl <30 mL/min) or renal failure due to potential for fluid retention and hyperkalemia.
Liver impairment	Contraindicated in Child-Pugh class B or C (moderate to severe hepatic impairment). For Child-Pugh class A, lowest possible effective dose should be used with close monitoring of liver function.
Pediatric use	Post-menarche adolescents: same dosing as adults (one tablet daily for 21 days, then 7 days placebo). Safety and efficacy in pre-menarche girls have not been established.
Geriatric use	Not indicated for postmenopausal women. No specific geriatric dose adjustments; however, consider increased risk of thromboembolic events and cardiovascular disease in women aged >40 years who smoke or have other risk factors.

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for LARIN 1.5/30 (LARIN 1.5/30).

Breastfeeding	Small amounts of ethinyl estradiol and norethindrone transfer into breast milk, with a milk-to-plasma ratio approximately 0.2-0.3 for norethindrone and <0.1 for ethinyl estradiol. May reduce milk production and composition. Use caution and consider alternative contraception in nursing mothers.
Teratogenic Risk	First trimester: No consistent evidence of major malformations, but a small increased risk of cardiovascular defects and oral clefts cannot be excluded. Second and third trimesters: Associated with adverse fetal outcomes including low birth weight, preterm delivery, and neonatal withdrawal symptoms. Avoid use during pregnancy due to known risks.

Warnings & precautions

■ FDA Black Box Warning

Cigarette smoking increases risk of serious cardiovascular events. Risk increases with age and heavy smoking (≥15 cigarettes/day). Women over 35 who smoke should not use this product.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Current or history of venous thromboembolism","Cerebrovascular or coronary artery disease","Uncontrolled hypertension","Diabetes with vascular involvement","Known or suspected pregnancy","Liver tumors or active liver disease","Undiagnosed abnormal uterine bleeding","Hypersensitivity to any component","Cigarette smoking in women over 35"]

Clinical Precautions

Precautions

["Cardiovascular disease risk: smoking, hypertension, diabetes, hyperlipidemia","Thromboembolic events: increased risk in surgery, postpartum, or immobilization","Liver disease: discontinue if jaundice develops","Gallbladder disease: increased risk","Glucose intolerance: monitor in diabetics","Blood pressure elevation: monitor periodically","Depression: discontinue if severe"]

Clinical Tips & Counseling

Drug interactions

Loading safety data…

LARIN 1.5/30

Clinical safety rating: caution

Comprehensive clinical and safety monograph for LARIN 1.5/30 (LARIN 1.5/30).

How it works

What the body does with it

Metabolism	Ethinyl estradiol: primarily CYP3A4; norethindrone: primarily CYP3A4, with some reduction to active metabolites.
Excretion	Renal (40% as metabolites, <10% unchanged); fecal (50% as metabolites); biliary (minor).
Half-life	Ethinyl estradiol: 13-19 hours; Norethindrone: 7-9 hours. Steady-state achieved in ~5-7 days.
Protein binding	Ethinyl estradiol: 97-98% bound to albumin; Norethindrone: 93-99% bound to SHBG and albumin.
Volume of Distribution	Ethinyl estradiol: 2.5-5 L/kg; Norethindrone: 2-4 L/kg. Indicates extensive tissue distribution.
Bioavailability	Oral: Ethinyl estradiol ~40-50% (first-pass metabolism); Norethindrone ~50-60% (first-pass metabolism).
Onset of Action	Oral: contraceptive effect requires 7 days of continuous dosing; immediate if started on day 1 of menses.
Duration of Action	24 hours for contraceptive efficacy; requires daily dosing for sustained effect.

Classification & Brands

Dosing & administration

One tablet (norethindrone acetate 1.5 mg, ethinyl estradiol 30 mcg) orally once daily at the same time each day for 21 consecutive days, followed by 7 days of placebo tablets.

Dosage form	TABLET
Renal impairment	No dose adjustment required in mild to moderate renal impairment (CrCl >=30 mL/min). Use contraindicated in severe renal impairment (CrCl <30 mL/min) or renal failure due to potential for fluid retention and hyperkalemia.
Liver impairment	Contraindicated in Child-Pugh class B or C (moderate to severe hepatic impairment). For Child-Pugh class A, lowest possible effective dose should be used with close monitoring of liver function.
Pediatric use	Post-menarche adolescents: same dosing as adults (one tablet daily for 21 days, then 7 days placebo). Safety and efficacy in pre-menarche girls have not been established.
Geriatric use	Not indicated for postmenopausal women. No specific geriatric dose adjustments; however, consider increased risk of thromboembolic events and cardiovascular disease in women aged >40 years who smoke or have other risk factors.

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for LARIN 1.5/30 (LARIN 1.5/30).

Breastfeeding	Small amounts of ethinyl estradiol and norethindrone transfer into breast milk, with a milk-to-plasma ratio approximately 0.2-0.3 for norethindrone and <0.1 for ethinyl estradiol. May reduce milk production and composition. Use caution and consider alternative contraception in nursing mothers.
Teratogenic Risk	First trimester: No consistent evidence of major malformations, but a small increased risk of cardiovascular defects and oral clefts cannot be excluded. Second and third trimesters: Associated with adverse fetal outcomes including low birth weight, preterm delivery, and neonatal withdrawal symptoms. Avoid use during pregnancy due to known risks.

Warnings & precautions

■ FDA Black Box Warning

Cigarette smoking increases risk of serious cardiovascular events. Risk increases with age and heavy smoking (≥15 cigarettes/day). Women over 35 who smoke should not use this product.