Efficacy and safety of a levonorgestrel enteric-coated tablet as an over-the-counter drug for emergency contraception

a Phase IV clinical trial

Chen, Q.-J.
Xiang, W.-P.
Zhang, D.-K.
Wang, R.-P.
Luo, Y.-F.
Kang, J.-Z.
Cheng, L.-N.

¹Shanghai Institute of Planned Parenthood Research, Shanghai, PR China
²Family Planning Research Institute, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, PR China
³Department of Gynecology and Obstetrics, The Sixth Affiliated Hospital of SUN YAT-SEN University, Guangzhou, PR China
⁴Family Planning Institute of Hunan Province, Changsha, PR China
⁵Jilin Hospital of Reproductive Health, Changchun, PR China
⁶International Peace Maternity and Child Health Hospital, Shanghai Jiaotong University, Shanghai, PR China

Correspondence address. E-mail: [email protected]

† Two equal first authors.

Received March 16, 2011

Accepted May 12, 2011

Human Reproduction 26(9):p 2316-2321, September 2011. | DOI: 10.1093/humrep/der181

BACKGROUND

An enteric-coated levonorgestrel emergency contraceptive pill (E-LNG-ECP) is an improved formulation, in terms of side effects, which both dissolves and is absorbed in the intestine. Our aim was to evaluate the efficacy and safety of E-LNG-ECP as an over-the-counter (OTC) drug for emergency contraception (EC) in Chinese women.

METHODS

A Phase IV clinical trial was conducted in five family planning clinics in China. Women seeking EC within 72 h after unprotected sexual intercourse or contraceptive failure who met the inclusion criteria were recruited. The efficacy of contraception (primary end-point was pregnancy rate), side effects (i.e. safety) and the value of E-LNG-ECP for EC were investigated.

RESULTS

Of 2445 women (aged 15–48 years) who took E-LNG-ECP with follow-up to determine pregnancy, only five pregnancies (0.2%) occurred. The efficacy of contraception was 95.3%. In total, 6.5% of women reported at least one adverse event after taking E-LNG-ECP, and no serious adverse events were reported. Only four subjects (0.16%) reported vomiting. The incidence of menstrual cycle disturbance was 20.1% after taking E-LNG-ECP. Subjects who had previously taken ECPs (54.4% of these women) rated the acceptability of E-LNG-ECP at 9.36 (on a 10-point scale) higher (P<0.05) than the rating of other LNG-EC pills taken previously.

CONCLUSIONS

The study found that E-LNG-ECP was effective, safe and well tolerated as an OTC drug. However, an randomized controlled trial should be performed to compare standard LNG tablets with E-LNG-ECP.