Yuzpe regimen

The Yuzpe Regimen is a method of emergency contraception using a combination of estrogen and progestogen hormones (100 mcg ethinylestradiol and 0.5 mg of levonorgestrel ASAP and again in 12 hrs) and started within 72 hours of sexual intercourse. It has been superseded by a progestogen-only hormonal regimen (1.5 mg of levonorgestrel ASAP) .

This treatment decreases the chance of a woman who has had unprotected sex of becoming pregnant. The sooner this is started, the more effective it is and the effectiveness after 72 hours after sexual intercourse is greatly reduced.

These hormones are administered as a number of combined oral contraceptive pills (COCPs). Each dose can vary from 2 to 5 pills depending on the brand of medication being used. People concurrently taking certain regular medications (e.g. rifamycin and many anticonvulsant drugs) that enhance the liver's break down of other drugs, must use an even higher hormone dose and may be better advised to use alternatively the insertion of a copper IUD or 30 mg of ulipristal acetate.

The Yuzpe regimen works primarily by inhibiting ovulation. The method is not guaranteed to prevent pregnancy and whilst the hormones may make the subsequent period come a few days early or late, a pregnancy test should be carried out if the period is more than 3 days late. The Yuzpe Regimen does not protect against sexually transmitted diseases.

Subsequently, the World Health Organization (WHO) undertook an investigation into the use of progestogen-only tablets as an Emergency Hormonal Contraceptive (i.e. without any estrogen component). This showed greater efficacy with reduced side effects and has therefore superseded the Yuzpe method. A single dose of 10 mg mifepristone is also more effective than the Yuzpe regime.

Some temporary, but usually minor, reactions include:

Should vomiting occur within 3 hours of taking a dose, then insufficient hormones may have been absorbed to provide the full contraceptive cover and an additional dose should be taken. Measures that may help to prevent nausea or vomiting include:

...
Wikipedia