Ulipristal acetate, sometimes shortened to UPA, is an emergency contraceptive pill. It is used to lower the chance of pregnancy after sex without protection, or after a birth control method has failed, such as a condom that tore. It is a single tablet taken by mouth as soon as possible, and within 120 hours (5 days) of unprotected sex. Ulipristal acetate works mainly by stopping or delaying the release of an egg from the ovary. It is meant for occasional, emergency use only and is not a replacement for regular birth control.

Ulipristal acetate belongs to a group of medicines called selective progesterone receptor modulators. Progesterone is a natural hormone that helps the body get ready to release an egg and prepare for pregnancy. Ulipristal acetate attaches to the same places in the body that progesterone uses, which blocks or changes the hormone's effect.

When the 30 mg tablet is taken shortly before an egg would normally be released, it can push back that release, which is the main way it lowers the chance of pregnancy. It may also cause changes in the lining of the womb.

The tablet is used for emergency contraception, and the window for use is up to 5 days after unprotected sex. It can be taken at any point in the menstrual cycle and with or without food.

Ulipristal acetate does not end a pregnancy that has already started. It should not be taken by anyone who knows or suspects they are already pregnant. It does not protect against HIV or other sexually transmitted infections.

After taking it, the next period may come earlier or later than expected. In studies, 19% of women had their period more than 7 days late. If a period is more than 7 days late, a pregnancy test is needed. Fertility can return quickly after taking it, so a barrier method such as a condom is needed for the rest of that cycle.

A lower-strength 5 mg form of Ulipristal acetate has been used in Europe for uterine fibroids, which are non-cancerous growths in the womb. European regulators restricted that use in 2020 after rare but serious liver injury, some cases needing a liver transplant. The same regulators said no liver concern has been raised with the single-dose emergency contraceptive. Any use of Ulipristal acetate should follow a doctor's advice.

1. A wider time window: Ulipristal acetate can be taken up to 120 hours (5 days) after unprotected sex.
2. Shown to lower pregnancy rates: In a study of 1,242 women who took it between 48 and 120 hours after sex, 2.2% became pregnant, compared with an expected rate of 5.5% without emergency contraception. In another study of 844 women who took it within 72 hours, 1.9% became pregnant, against an expected 5.6%.
3. One tablet only: The full treatment is a single tablet, so there is no schedule to remember.
4. Flexible with meals: It can be taken with or without food.
5. Studied in teenagers: Safety and effectiveness in girls aged 17 and younger were similar to those in adults in studies.

Common Side Effects (Usually Mild and may lessen with continued use)

• Headache (reported by about 18% of women in studies)
• Stomach pain (about 12%)
• Nausea, or feeling sick (about 12%)
• Painful periods (about 9%)
• Tiredness (about 6%)
• Dizziness (about 5%)
• Spotting or bleeding between periods (reported by 9% of women in studies)
• A change in the timing of the next period, either earlier or later than expected
• Acne (reported after the medicine came on the market)

Serious Side Effects (Seek Urgent Medical Attention)

• Severe pain in the lower stomach, especially 3 to 5 weeks after taking the tablet. This can be a sign of an ectopic pregnancy, which is a pregnancy growing outside the womb, often in a fallopian tube. It needs emergency care.
• Signs of an allergic reaction, such as rash, itching, hives, or swelling of the eyes, face, tongue, or throat.

• Take the tablet as soon as possible after unprotected sex or a birth control failure. The label allows up to 120 hours (5 days).
• Take the tablet by mouth.
• It can be taken with or without food, and at any time of day.
• It is taken as a single tablet. There is no daily course to follow.
• If you vomit within 3 hours of taking the tablet, contact your doctor or pharmacist straight away. The label says a repeat dose may need to be considered.
• Keep the tablet in its blister pack inside the box until you are ready to take it.
• Tell your doctor about all the other medicines and herbal products you use, as some can make Ulipristal acetate work less well.
• For hormonal birth control afterwards, the label says to wait at least 5 days before starting or restarting it, and to use a barrier method such as condoms until your next period.

Ulipristal acetate is a selective progesterone receptor modulator. A "receptor" is like a lock on a cell, and a hormone is the key that fits it. Progesterone is the key that normally fits the progesterone receptor. Ulipristal acetate fits the same lock. It partly blocks progesterone and partly acts like a weak version of it. This mix of blocking and weak copying is what "modulator" means.

Each month, a small sac in the ovary called a follicle grows and then bursts to release an egg. This is called ovulation. A surge of a hormone called LH (luteinising hormone) triggers the burst.

When Ulipristal acetate is taken in the days before this surge, it can delay the follicle from bursting for at least five days in most women. This delay is thought to be the main way it prevents pregnancy.

Ulipristal acetate does not work if taken on the day the LH surge peaks, when ovulation is about to happen. It may also cause changes in the lining of the womb that could make it harder for a fertilised egg to attach, and this may add to its effect.

After it is swallowed, Ulipristal acetate reaches its highest level in the blood in about 1 hour. The liver breaks it down mainly using an enzyme called CYP3A4. An enzyme is a protein that helps chemical changes happen in the body. The drug leaves the body slowly, with a half-life of about 32 hours. Half-life means the time it takes for the amount in the blood to fall by half.

• Take the tablet as soon as you can after unprotected sex. Do not wait until the last day of the 5-day window.
• If you vomit within 3 hours of taking it, contact your doctor or pharmacist about a possible repeat dose.
• Use condoms or another barrier method every time you have sex until your next period.
• Wait at least 5 days before starting or restarting birth control pills or other hormonal birth control.
• Tell your doctor if you take certain seizure medicines, rifampicin for tuberculosis, or the herbal product St. John's Wort, as these can make Ulipristal acetate less effective.
• Expect that your next period may come earlier or later than usual.
• Take a pregnancy test if your period is more than 7 days late.
• Get emergency help for severe lower stomach pain in the weeks after taking it.
• Talk to your doctor about a regular birth control method for the future.

• Store between 20°C and 25°C (68°F to 77°F).
• Protect the tablet from light. Keep it in its blister card inside the original box until you are ready to take it.
• Keep it away from excess heat and moisture.
• Keep it out of the reach and sight of children and pets.

• Food and fatty meals: Taking Ulipristal acetate with a high-fat breakfast lowered its peak level in the blood by about 40 to 45% and delayed when that peak was reached, from about 45 minutes to 3 hours. The label says this is not expected to affect how well it works, so it can be taken with or without food.
• St. John's Wort: This herbal product, sometimes taken for low mood, can lower the level of Ulipristal acetate in the body and may make it less effective. Tell your doctor if you use it.
• Alcohol: The US label does not list an interaction between Ulipristal acetate and alcohol.

• Medicines that speed up CYP3A4 (the liver enzyme that breaks down Ulipristal acetate): These can sharply lower the level of Ulipristal acetate in the blood and may make it less effective. In one study, rifampicin lowered its levels by about 90%. The label advises avoiding it with:
• Barbiturates (a group of sedative and seizure medicines)
• Bosentan (used for high blood pressure in the lungs)
• Carbamazepine, oxcarbazepine, phenytoin, felbamate, and topiramate (seizure medicines)
• Griseofulvin (an antifungal)
• Rifampicin, also called rifampin (an antibiotic used for tuberculosis)
• St. John's Wort (a herbal product)
• Medicines that slow down CYP3A4: Antifungals such as itraconazole and ketoconazole can raise the level of Ulipristal acetate in the blood. Tell your doctor if you take them.
• Hormonal birth control: Pills or other methods that contain a progestin (a man-made form of progesterone) may stop Ulipristal acetate from delaying ovulation. Taking them close together may make Ulipristal acetate less effective, so the label advises against using them together. The label advises waiting at least 5 days after Ulipristal acetate before starting hormonal birth control.
• Medicines carried by P-glycoprotein: Lab studies suggest Ulipristal acetate may block P-glycoprotein, a pump that moves some drugs in and out of cells. This could affect medicines that rely on this pump. Tell your doctor about every medicine you take.

• Known or suspected pregnancy: Ulipristal acetate must not be used. It does not end an existing pregnancy.
• History of ectopic pregnancy: This is not a reason to avoid Ulipristal acetate. If you become pregnant or get lower stomach pain after taking it, see a doctor promptly, because doctors check for an ectopic pregnancy.
• Liver disease: The emergency tablet has not been studied in people with liver disease. The 5 mg fibroid form has caused rare, serious liver injury, and European regulators have restricted its use.
• Kidney disease: Ulipristal acetate has not been studied in people with kidney disease. Tell your doctor if you have kidney problems.
• Lactose intolerance: The tablet contains lactose monohydrate. Tell your doctor if you have been told you cannot take lactose.
• Post-menopause: Ulipristal acetate is not intended for women who have gone through menopause.

• The US label for the emergency contraceptive describes one 30 mg tablet taken by mouth as a single dose, as soon as possible and within 120 hours (5 days) of unprotected sex or birth control failure.
• It is not a daily medicine. The label states that using it more than once in the same menstrual cycle is not recommended.
• If vomiting happens within 3 hours of the tablet, the label says a repeat dose may be considered. This is a decision for your doctor.
• Always take Ulipristal acetate exactly as your doctor or pharmacist tells you. Do not take extra tablets on your own.

• In a clinical study, a small number of people took single doses up to 4 times the usual dose without any side effects being reported.
• If you or someone else has taken more than the prescribed dose, or a child has swallowed the tablet, contact a doctor or go to the nearest hospital emergency department.
• Take the medicine pack with you so the medical team can see what was taken.

• Ulipristal acetate is a single-dose emergency medicine, so there is no regular schedule to miss.
• If you meant to take it and have not yet done so, take it as soon as possible. It is meant to be taken within 120 hours (5 days) of unprotected sex.
• If more than 5 days have passed, speak to your doctor about your options.
• Never take two tablets to make up for a delay.

• Severe pain in the lower stomach, especially 3 to 5 weeks after taking Ulipristal acetate. Go to the nearest emergency room, as this may be an ectopic pregnancy.
• Vomiting within 3 hours of taking the tablet.
• A period that is more than 7 days later than expected.
• Signs of an allergic reaction, such as rash, hives, itching, or swelling of the face, eyes, tongue, or throat.
• If you think you may be pregnant after taking it.