Levonorgestrel Female Sex Hormones Pharmaceutical Materials No 797-63-7

Levonorgestrel Female Sex Hormones Pharmaceutical Materials No 797-63-7

Product Name: Levonorgestrel
Synonyms: 13-ethyl-17-alpha-ethynyl-17-beta-hydroxy-4-gonen-3-one;13-ethyl-17-alpha-ethynylgon-4-en-17-beta-ol-3-one;13-ethyl-17-hydroxy-19-dinor-17-alpha-pregn-4-en-20-yn-3-on(+)-1;17-alpha-ethinyl-13-beta-ethyl-17-beta-hydroxy-4-estren-3-one;17-beta-hydroxy-18-methyl-19-nor-17-alpha-pregn-4-en-20-yn-3-one;17-ethynyl-18-methyl-19-nortestosteron;17-ethynyl-18-methyl-19-nortestosterone;18-methyl-17-alpha-ethynyl-19-nortestosterone
: 797-63-7
MF: C21H28O2
MW: 312.45
EINECS: 212-349-8

Levonorgestrel Medical uses

1. Birth control pills
At low doses, levonorgestrel is used in monophasic and triphasic formulations of combined oral contraceptive pills, with available monophasic doses ranging from 100-250 µg, and triphasic doses of 50 µg/75 µg/125 µg. At very low daily dose of 30 µg, levonorgestrel is used in some progestogen only pill formulations.

2. Emergency birth control
Levonorgestrel is used in emergency contraceptive pills (ECPs), both in a combined Yuzpe regimen which includes estrogen, and as a levonorgestrel-only method. The levonorgestrel-only method uses levonorgestrel 1.5 mg (as a single dose or as two 0.75 mg doses 12 hours apart) taken within 3 days of unprotected sex, with one study indicating that beginning as late as 120 hours (5 days) after intercourse could be effective.

The primary mechanism of action of levonorgestrel as a progestogen-only emergency contraceptive pill is, according to International Federation of Gynecology and Obstetrics (FIGO), to prevent fertilization by inhibition of ovulation and thickening of cervical mucus. FIGO has stated that: "review of the evidence suggests that LNG [levonorgestreol] ECPs cannot prevent implantation of a fertilized egg. Language on implantation should not be included in LNG ECP product labeling." In November 2013, the European Medicines Agency (EMA) approved a change to the label saying it cannot prevent implantation of a fertilized egg.

Other studies still find the evidence to be unclear. While it is unlikely that emergency contraception affects implantation it is impossible to completely exclude the possibility of post-fertilization effect. In November 2013, the EMA also approved a change to the label for HRA Pharmas NorLevo saying: "In clinical trials, contraceptive efficacy was reduced in women weighing 75 kg [165 pounds] or more, and levonorgestrel was not effective in women who weighed more than 80 kg [176 pounds]." In November 2013 and January 2014, the FDA and the EMA said they were reviewing whether increased weight and body mass index (BMI) reduce the efficacy of emergency contraceptives.

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