Comparative Pharmacology
Head-to-head clinical analysis: IMPLANON versus NEXPLANON.
Peer-Reviewed Evidence
Head-to-head clinical analysis: IMPLANON versus NEXPLANON.
IMPLANON vs NEXPLANON
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Etonogestrel, a progestin, binds to progesterone and androgen receptors, suppressing gonadotropin release (FSH, LH) and preventing ovulation. It also increases cervical mucus viscosity, impeding sperm penetration, and alters endometrial morphology.
Progestin-only contraceptive that suppresses ovulation primarily by inhibiting the mid-cycle LH surge. It also thickens cervical mucus, impeding sperm penetration, and alters endometrial lining.
Insert 1 rod (68 mg etonogestrel) subdermally in the inner upper arm; replacement every 3 years.
68 mg subdermal implant inserted in the inner upper arm; provides contraception for up to 3 years.
None Documented
None Documented
Terminal elimination half-life is approximately 25-30 hours; significant interindividual variability
Terminal elimination half-life approximately 25 hours (range 20-30 hours) after removal; steady-state achieved within 3-4 days; clinical effect persists for 3-4 weeks post-removal due to residual subcutaneous depot.
Metabolites primarily excreted in urine (approximately 50%) and feces (30-35%)
Renal (40-50% as metabolites), fecal (30-40% as metabolites), with <1% unchanged in urine; enterohepatic circulation contributes to prolonged elimination.
Category C
Category C
Contraceptive
Contraceptive