Comparative Pharmacology
Head-to-head clinical analysis: PLAN B versus PLAN B ONE STEP.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PLAN B versus PLAN B ONE STEP.
PLAN B vs PLAN B ONE-STEP
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Levonorgestrel, a progestin, prevents pregnancy primarily by inhibiting ovulation and altering cervical mucus to impede sperm penetration. It may also inhibit implantation.
Levonorgestrel is a progestin that prevents pregnancy primarily by inhibiting ovulation and altering cervical mucus to impede sperm penetration. It may also interfere with fertilization and implantation.
One 1.5 mg tablet (levonorgestrel) orally as a single dose, taken as soon as possible within 72 hours of unprotected intercourse.
One 1.5 mg tablet orally as a single dose within 72 hours of unprotected intercourse.
None Documented
None Documented
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).
Terminal elimination half-life is approximately 24 hours (range 16-32 hours) for levonorgestrel. This supports single-dose administration for emergency contraception.
Renal (approximately 50% as unchanged drug and metabolites); fecal (approximately 40% as metabolites); less than 1% biliary.
Renal (approximately 50%), with fecal elimination accounting for the remainder. Metabolites are excreted primarily in urine as glucuronide conjugates.
Category C
Category C
Emergency Contraceptive
Emergency Contraceptive