Comparative Pharmacology
Head-to-head clinical analysis: ELLA versus PLAN B.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ELLA versus PLAN B.
ELLA vs PLAN B
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Selective progesterone receptor modulator (SPRM) with antagonistic and partial agonistic activity. Delays or inhibits ovulation, alters endometrial receptivity, and impairs implantation.
Levonorgestrel, a progestin, prevents pregnancy primarily by inhibiting ovulation and altering cervical mucus to impede sperm penetration. It may also inhibit implantation.
30 mg orally as a single dose within 120 hours of unprotected intercourse.
One 1.5 mg tablet (levonorgestrel) orally as a single dose, taken as soon as possible within 72 hours of unprotected intercourse.
None Documented
None Documented
Terminal half-life is approximately 24.7 hours (range 20–30 hours), allowing for single-dose emergency contraception.
Terminal elimination half-life: 24-30 hours. Clinical context: The prolonged half-life supports single-dose regimen for emergency contraception; may be affected by obesity (shorter half-life in obese women).
Primarily fecal (≈86%) with minimal renal excretion (≈10%). Biliary elimination of metabolites is also significant.
Renal (approximately 50% as unchanged drug and metabolites); fecal (approximately 40% as metabolites); less than 1% biliary.
Category C
Category C
Emergency Contraceptive
Emergency Contraceptive