Comparative Pharmacology
Head-to-head clinical analysis: KYLEENA versus SEASONALE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: KYLEENA versus SEASONALE.
KYLEENA vs SEASONALE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Levonorgestrel is a progestin that suppresses endometrial proliferation, thickens cervical mucus, and induces endometrial atrophy. It also partially inhibits ovulation.
Seasonale is a combination oral contraceptive containing ethinyl estradiol and levonorgestrel. It suppresses gonadotropin release, inhibiting ovulation, and alters cervical mucus to reduce sperm penetration and endometrial lining to reduce implantation.
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.
One tablet (0.03 mg ethinyl estradiol and 0.15 mg levonorgestrel) orally once daily for 84 consecutive days, followed by 7 days of placebo.
None Documented
None Documented
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.
Ethinyl estradiol: terminal half-life 13-27 hours (mean 17 hours); levonorgestrel: terminal half-life 11-45 hours (mean 25 hours). Clinical context: Supports once-daily dosing; steady-state achieved within 5-10 days.
Renal (fecal negligible). Levonorgestrel is extensively metabolized; metabolites are excreted primarily in urine (40–68%) and to a lesser extent in feces (16–48%).
Renal excretion of metabolites (approximately 50-60% as glucuronide and sulfate conjugates of ethinyl estradiol and levonorgestrel) and fecal elimination (approximately 40-50%).
Category C
Category C
Contraceptive
Contraceptive, Combination Hormonal