KYLEENA
Clinical safety rating: caution
Comprehensive clinical and safety monograph for KYLEENA (KYLEENA).
Levonorgestrel is a progestin that suppresses endometrial proliferation, thickens cervical mucus, and induces endometrial atrophy. It also partially inhibits ovulation.
| Metabolism | Primarily hepatic through cytochrome P450 3A4 (CYP3A4) to conjugated and unconjugated metabolites. |
| Excretion | Renal (fecal negligible). Levonorgestrel is extensively metabolized; metabolites are excreted primarily in urine (40–68%) and to a lesser extent in feces (16–48%). |
| Half-life | Terminal elimination half-life is approximately 25 hours (range 18–30 hours) after repeated dosing; supports once-daily dosing but not applicable for IUD as systemic absorption is minimal. |
| Protein binding | ~55% bound to sex hormone-binding globulin (SHBG); ~42% to albumin; free fraction ~3%. Binding affinity to SHBG is about 10-fold higher than to albumin. |
| Volume of Distribution | Apparent Vd is approximately 1.5 L/kg (range 0.9–2.3 L/kg); reflects distribution into steroid-sensitive tissues (e.g., endometrium) and adipose tissue. |
| Bioavailability | Not applicable for oral administration (Kyleena is an IUD); systemic bioavailability from IUD is ~0.2% of the dose released, resulting in very low plasma levonorgestrel concentrations. |
| Onset of Action | Not applicable for contraception (IUD); contraceptive effect begins immediately after insertion. For other indications (e.g., heavy menstrual bleeding): onset of effect within 3–6 months. |
| Duration of Action | Licensed for 5 years of contraceptive use (approved label). Clinical efficacy in reducing menstrual bleeding persists for up to 5 years, with gradual decline in levonorgestrel release over time. |
KYLEENA (levonorgestrel-releasing intrauterine system 19.5 mg) is inserted into the uterine cavity by a healthcare professional. One system releases levonorgestrel at approximately 17.5 mcg/day initially, decreasing to 7.4 mcg/day after 1 year and 5.1 mcg/day after 3 years, and is effective for up to 5 years.
| Dosage form | SYSTEM |
| Renal impairment | No dose adjustment is required in patients with renal impairment. However, KYLEENA should be used with caution in patients with severe renal disease due to limited data. |
| Liver impairment | KYLEENA is contraindicated in patients with acute liver disease or liver tumor (benign or malignant). For mild hepatic impairment (Child-Pugh A), no dose adjustment is needed. Use in moderate to severe hepatic impairment (Child-Pugh B or C) has not been studied and is not recommended. |
| Pediatric use | KYLEENA is indicated for prevention of pregnancy in women of reproductive age. Safety and efficacy have not been established in patients under 18 years of age; however, use may be considered post-menarche based on clinical judgment. |
| Geriatric use | KYLEENA is not indicated for use in postmenopausal women. No geriatric-specific dosing adjustments are available as the drug is not intended for use in this population. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for KYLEENA (KYLEENA).
| Breastfeeding | Small amount of levonorgestrel excreted into breast milk (M/P ratio unknown). No adverse effects reported in nursing infants, but theoretical risk of hormonal disruption. Use during breastfeeding is generally acceptable; however, monitor infant for jaundice or unusual weight gain. |
| Teratogenic Risk | KYLEENA is contraindicated during pregnancy due to risk of pregnancy complications and fetal exposure to levonorgestrel. First trimester exposure: increased risk of ectopic pregnancy, spontaneous abortion, and fetal abnormalities (limb reduction defects, cardiac anomalies). Second/third trimester: risk of preterm labor, low birth weight, and fetal masculinization of female fetuses. Levonorgestrel crosses the placenta; use is not recommended. |
■ FDA Black Box Warning
None
| Serious Effects |
["Pregnancy or suspected pregnancy","Known or suspected breast cancer","Acute or recurrent pelvic inflammatory disease","Postpartum endometritis or infected abortion within past 3 months","Uterine cavity distortion (e.g., fibroids) preventing proper placement","Unexplained genital bleeding","Known or suspected cervical or uterine malignancy","Liver disease or tumor (benign or malignant)","Known hypersensitivity to any component of the device"]
| Precautions | ["Risk of ectopic pregnancy, especially in cases of pelvic inflammatory disease","Perforation of the uterine wall during insertion or use","Pelvic inflammatory disease (PID): increased risk in women with multiple sexual partners or history of STIs","Expulsion of the device commonly occurs in nulliparous women or during menses","Ovarian cysts: usually benign and asymptomatic","Breast cancer: use with caution in women with known or suspected breast cancer","Embedment of the device into the myometrium","Menstrual pattern changes: irregular bleeding or amenorrhea","Systemic effects: progestin-related side effects (mood changes, headache, acne, etc.)"] |
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| Fetal Monitoring | Confirm negative pregnancy test before insertion. Monitor for signs of pregnancy, ectopic pregnancy, and uterine perforation. If pregnancy occurs, evaluate for ectopic and assess IUD location via ultrasound. |
| Fertility Effects | Reversible contraceptive effect. Normal fertility returns promptly after removal. Delay in return to fertility may occur if inflammation or infection is present during use. |