New strength

Some of the views expressed in the following notes on newly approved products should be regarded as preliminary, as there may have been limited published data at the time of publication, and little experience in Australia of their safety or efficacy. However, the Editorial Executive Committee believes that comments made in good faith at an early stage may still be of value. Before new drugs are prescribed, the Committee believes it is important that more detailed information is obtained from the manufacturer's approved product information, a drug information centre or some other appropriate source.

Postinor-2 (Schering)
750 mg tablets
Approved indication: emergency contraception
Australian Medicines Handbook Section 17.1.4

For many years health professionals have been cutting up packets of contraceptive pills to provide women with post-coital contraception. This use of the combined pill in the Yuzpe regimen has never been approved by the Therapeutic Goods Administration. An alternative to this regimen was a high dose of progestogen, but no suitable formulations were available.

This new strength of levonorgestrel has been approved for emergency contraception. One tablet should be taken within 72 hours of unprotected intercourse. This is followed by a second tablet 12 hours later. The sooner treatment begins the more effective it is.

A double-blind study compared this regimen with the Yuzpe regimen. There were 11 pregnancies in the 976 women who took levonorgestrel, and31 in the 979 women who used the Yuzpe regimen. When the women's menstrual cycles and probability of conception were taken into account levonorgestrel prevented 86% of expected pregnancies and the Yuzpe regimen prevented 58%.1

Both regimens cause nausea and vomiting, however they occur significantly less frequently with levonorgestrel. If the woman vomits within two hours of taking levonorgestrel an additional tablet can betaken.

Women should not use this product as their regular form of contraception. A request for emergency contraception is an opportunity to discuss the woman's ongoing contraceptive needs. This should not be overlooked even if levonorgestrel becomes available, as it is in the UK, from pharmacies without a prescription.2