Levonorgestrel

Administration

• Type: Contraceptive
• Dosage Forms: Tablet 0.75mg, 1.5mg
• Routes of Administration: oral, intrauterine (IUD)
• Common Trade Names: Plan-B, most brands of combination OCPs, Mirena

Adult Dosing

• Emergency contraception: 0.75mg PO q12 x 2 OR 1.5mg PO once, as soon as possible within 72 hours of unprotected sex

Pediatric Dosing

• See above

Special Populations

• Pregnancy Rating: X
• Lactation risk: Infant risk cannot be ruled out
• Renal Dosing: no adjustment
• Hepatic dosing: no adjustment

Contraindications

• Allergy to class/drug
• Pregnancy
• IUDs only:
  • Active pelvic infection or STD
  • Immunocompromise
  • Known or suspected breast, uterine, or cervical cancer
  • Acute liver disease or liver tumor
  • Structural uterine anomaly including fibroids that distort uterine cavity

Adverse Reactions

Serious

• Pills:
  • DVT/PE, stroke, MI
  • Depression, suicidality
• IUDs:
  • Ectopic pregnancy
  • Uterine perforation
  • PID, sepsis

Common

• Nausea, abdominal pain
• Headache, dizziness
• Abnormal vaginal bleeding, breast tenderness, ovarian cysts
• Pills:
  • Acne
  • Fatigue
• IUDs:
  • Pelvic pain, vulvovaginitis
  • Irregular menses, hypomenorrhea/amenorrhea

Pharmacology

• Half-life: Oral: 17-27.5h
• Metabolism: Hepatic, primarily via CYP3A4
• Excretion: Renal, fecal

Mechanism of Action

• Progestogen; inhibits ovulation or fertilization by altering tubal transport of sperm and/or ova

See Also

• Emergency contraception
• IUD