Chemical Name:13β-ethyl-17β-hydroxy-18, 19-dinor-17α-pregn-4-en-20-yn-3-one
Molecular Formula: C21H28O2
Molecular Weight: 312.47
CAS: 797-63-7

Levonorgestrel Description and Indication

Levonorgestrel is a synthetic progestogen used as an active ingredient in a number of hormonal contraceptives. The progestogen prevents pregnancy by inhibiting ovulation and by causing the cervical mucus to thicken, thereby making it more difficult for sperm to move toward the uterus. Levonorgestrel is also used for long-term contraception for a period of upto 5 years at a time. It is used exclusively as a clinical remedial measure to prevent pregnancy.

Levonorgestrel Mechanism of Action

Pregnancy may be prevented through several mechanisms:

Levonorgestrel is effective under all of these mechanisms, but is not effective once the implantation process has begun.

Levonorgestrel Dosage

Levonorgestrel is used both as an emergency contraceptive as well as for long-term prevention of pregnancy. For the former it can be administered as an oral tablet after unprotected sexual intercourse. One 0.75 mg tablet should be taken as soon as possible within 72 hours of intercourse and a second 0.75 mg tablet should be taken 12 hours after the first dose. It may be used at any time during the menstrual cycle.

For long-term pregnancy prevention an Intra-uterine system is inserted into the uterine cavity which releases 20 mcg Levonorgestrel/day over 5 years. It may be removed and replaced with a new unit at anytime during menstrual cycle. One system is not to be left in place for more than 5 years.

Levonorgestrel Contraindications

Levonorgestrel is contraindicated in case of:

Levonorgestrel Adverse Drug Effects

Levonorgestrel Drug Interactions

Levonorgestrel may show drug interaction with following:

Levonorgestrel Formulations

Levonorgestrel Brands

These are the following brands available for Levonorgestrel:

  • Alesse
  • Mirena
  • Nordette
  • Norplant
  • Ovral
  • Microgynon
  • Plan B One Step
  • Plan B
  • Postinor-2
  • Seasonale
  • Tri-levlen