LEVLITE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for LEVLITE (LEVLITE).
Levonorgestrel is a progestin that suppresses ovulation by inhibiting gonadotropin release (LH and FSH) and alters cervical mucus, endometrial thickness, and tubal motility.
| Metabolism | Hepatic via CYP3A4; reduced to inactive metabolites; excreted in urine and feces. |
| Excretion | Renal: ~50% (30% as unchanged drug, 20% as metabolites); Fecal: ~40%; Biliary: minor |
| Half-life | Terminal elimination half-life: 21-28 hours; clinical context: permits once-daily dosing |
| Protein binding | Levonorgestrel: ~99% bound to sex hormone-binding globulin (SHBG) and albumin; Ethinyl estradiol: ~98% bound to albumin |
| Volume of Distribution | Levonorgestrel: 1.8 L/kg; Ethinyl estradiol: 2.5 L/kg; clinical meaning: extensive tissue distribution |
| Bioavailability | Oral: ~100% for both levonorgestrel and ethinyl estradiol (high bioavailability due to minimal first-pass metabolism) |
| Onset of Action | Oral: 1-2 hours (serum progesterone elevation); peak effect: 48-72 hours for ovulation inhibition |
| Duration of Action | 21-day cycle (active pills) with 7-day hormone-free interval; clinical note: sustained suppression of gonadotropins during active phase |
One tablet (levonorgestrel 0.1 mg, ethinyl estradiol 0.02 mg) orally once daily for 21 days, followed by 7 placebo tablets.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment. Not studied in severe renal impairment (GFR <30 mL/min); use with caution. |
| Liver impairment | Contraindicated in severe hepatic disease (Child-Pugh Class C). For mild to moderate impairment (Child-Pugh A/B), use with caution and monitor liver function. |
| Pediatric use | Not indicated for use in postmenarchal pediatric patients; safety and efficacy not established in prepubertal children. |
| Geriatric use | Not indicated for use in postmenopausal women; no specific geriatric dosing studies available. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for LEVLITE (LEVLITE).
| Breastfeeding | Excreted in breast milk in small amounts. Ethinyl estradiol concentration in milk ~0.02-0.1 ng/mL; levonorgestrel M/P ratio ~0.35-1.0. No adverse effects reported at typical doses. May reduce milk production; use caution in lactating women, especially with high doses. |
| Teratogenic Risk | FDA Pregnancy Category X. Ethinyl estradiol and levonorgestrel are contraindicated in pregnancy due to risk of fetal harm, including cardiovascular defects and limb reduction defects from first-trimester exposure. Second and third trimester exposure may be associated with genitourinary abnormalities and masculinization of female fetuses. |
■ FDA Black Box Warning
Cigarette smoking increases risk of serious cardiovascular events. Women over 35 who smoke should not use combination hormonal contraceptives.
| Serious Effects |
["Known or suspected pregnancy","Undiagnosed abnormal genital bleeding","Severe hepatic disease","Known or suspected breast cancer","History of thromboembolic disorders","Hypersensitivity to levonorgestrel"]
| Precautions | ["Thrombotic disorders","Hepatic disease","Hypertension","Diabetes","Gallbladder disease","Depression","Ectopic pregnancy risk (emergency contraception)","Reduced efficacy with CYP3A4 inducers"] |
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| Fetal Monitoring | Not indicated during pregnancy as product is contraindicated. If exposure occurs, monitor fetus with high-resolution ultrasound and echocardiography. In postpartum use, monitor infant for jaundice, weight gain, and developmental milestones. |
| Fertility Effects | Suppresses ovulation; reversible upon discontinuation. No permanent adverse effects on fertility. Return to baseline fertility typically occurs within 1-3 cycles after cessation. |