ulipristaalatsetaat

Uliprastaalatsetaat, known in English as ulipristal acetate, is an oral medication that acts as a selective progesterone receptor modulator (SPRM). It is the acetate salt of ulipristal and is used in two main clinical contexts: emergency contraception and the treatment of symptomatic uterine fibroids.

Mechanism of action: As an SPRM, ulipristal acetate binds to the progesterone receptor and exhibits tissue-specific agonist or antagonist effects. In the endometrium it can reduce proliferative activity and regulate bleeding, while in the context of ovulation it can delay ovulation, contributing to its effectiveness as emergency contraception.

Medical uses: For emergency contraception, a single 30 mg tablet is taken within five days of unprotected intercourse. For uterine fibroids, a daily 5 mg dose may be prescribed for a limited period (typically up to three months) under specialist supervision to reduce heavy bleeding and other fibroid-related symptoms.

Pharmacokinetics: After oral administration, ulipristal acetate is absorbed with peak plasma levels typically reached within 1 to 3 hours. It is extensively bound to plasma proteins and metabolized in the liver, mainly by the CYP3A4 enzyme, with active metabolites formed. The elimination half-life is in the range of about 32 to 38 hours, and it is excreted in urine and feces.

Safety and precautions: Common adverse effects include headache, nausea, abdominal pain, dizziness, breast tenderness, and irregular vaginal bleeding. There is a rare but serious risk of liver injury; use is contraindicated in pregnancy and cautioned in hepatic impairment. Drug interactions with strong CYP3A4 inducers can affect levels of ulipristal acetate, and liver function monitoring may be recommended in some regimens.

Regulatory status: Ulipristal acetate products have undergone regulatory review with safety warnings in some jurisdictions, leading to restricted use and specific monitoring guidelines in certain settings.