Source: Registered Drug Product Database (NG) Publisher: Name: ROYAL GROUP Address: ONB-E/2, Mehar sons Estate, Talpur Road, Karachi-74000, Pakistan Phone: +92-21-32400270 Extension: 232 Fax : +92-21-32412322 Email: info@royalgroupweb.com Manufactured by: HUAZHONG PHARMACEUTICAL CO., LTD, No. 118, Xianshan Road, Xiangyang City, Hubei, China
Oral contraceptive
ATC code: G03AD01
The primary mechanism of action is blockade and/or delay of ovulation via suppression of the luteinizing hormone (LH) peak. Levonorgestrel interferes with the ovulatory process only if it is administered before the onset of the LH surge. Levonorgestrel has no emergency contraceptive effect when administered later in the cycle.
In clinical trials, the proportion of pregnancies avoided after the use of Levonorgestrel varied from 52% (Glasier, 2010) to 85% (Von Hertzen, 2002) of expected pregnancies. Efficacy appears to decline with time after intercourse.
There is limited and inconclusive data on the effect of high body weight/high BMI on the contraceptive efficacy. In three WHO studies no trend for a reduced efficacy with increasing body weight/BMI was observed (Table 1), whereas in the two other studies (Creinin et al., 2006 and Glasier et al., 2010) a reduced contraceptive efficacy was observed with increasing body weight or BMI (Table 2). Both meta-analyses excluded intake later than 72 hours after unprotected intercourse (i.e. off-label use of Levonorgestrel) and women who had further acts of unprotected intercourse.
At the used regimen, Levonorgestrel is not expected to induce significant modifications of blood clotting factors, and lipid and carbohydrate metabolism
Bioavailability of oral Levonorgestrel is approximately 100 percent. In the plasma, it is strongly bound to SHBG. Levonorgestrel is eliminated via kidney (60-80%) and liver (40-50%).
After oral administration of 1.5 mg Levonorgestrel, the plasma terminal half-life of the product is estimated to 43 hours. The maximal plasma concentration of Levonorgestrel (approximately 40 nmol/l) is reached within 3 hours. Levonorgestrel is hydroxylated in the liver and the metabolites are excreted as glucuronide conjugates.
Nonclinical data reveal no special hazard for humans, beyond the information included in other sections of the SPC. Animal experiments with Levonorgestrel have shown virilization of female fetuses at high doses.
A preclinical study conducted in mice showed no effect on fertility in the progeny of treated dams. Two studies investigating the consequence of exposure to Levonorgestrel on the development of pre-embryos before implantation, showed that Levonorgestrel had no adverse effects on fertilisation and the in vitro growth of mouse pre-embryos.
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