Levonelle one step is commonly known as ‘the morning after pill’. It can be bought without a prescription from pharmacies and is taken to reduce the chances of becoming pregnant after unprotected sex or failure of a contraceptive method.
How does it work?
Levonelle one step tablets contain the active ingredient levonorgestrel, which is a synthetic derivative of the naturally occurring female sex hormone, progesterone.
It is not fully understood how this medicine prevents pregnancy. It is thought to work by preventing ovulation and fertilisation and also by altering the lining of the womb, depending on which stage of the menstrual cycle the woman is at.
In a woman’s normal menstrual cycle, an egg matures and is released from the ovaries (ovulation). The ovary then produces progesterone, which prevents the release of further eggs. Levonorgestrel, tricks the body processes into thinking that ovulation has already occurred, as it provides high levels of synthetic progesterone. This prevents the release of eggs from the ovaries.
Levonorgestrel also increases the thickness of the natural mucus at the neck of the womb (cervix), making it more difficult for sperm to cross from the vagina into the womb. By preventing sperm entering the womb, successful fertilisation of any egg that is there is less likely.
Levonorgestrel is also thought to alter the lining of the womb, preventing it from being prepared for a fertilised egg. This means that if an egg is released from the ovaries and is fertilised, it cannot implant into the womb and therefore pregnancy is avoided.
The whole process from fertilisation to implantation in the womb can take up to three days, so the morning after pill can only stop pregnancy from occuring for up to 72 hours after unprotected sex. The sooner it is taken after unprotected sex, the more effective it will be.
It is estimated that 84 per cent of pregnancies will be prevented if this morning-after pill is taken within 72 hours of unprotected sex. The tablet is more effective at preventing pregnancy the earlier it is taken, so it is important to take it as soon as possible after unprotected sex, rather than delay to the third day.
How do I take it?
There is one tablet to be taken. It should be taken as soon as possible after unprotected sex, preferably within 12 hours and no later than 72 hours.
If you are sick within two hours of taking the tablet, another one should be taken immediately. You should consult your doctor, pharmacist or family planning clinic for advice and to get another tablet.
Levonelle one step cannot be sold from pharmacies to girls under 16 years of age except in exceptional circumstances. Girls under 16 who need the morning after pill are advised to consult a doctor, family planning clinic or casualty department at a hospital. Some minor injuries departments at hospitals also provide the morning after pill.
Your pharmacist will ask about your last period and when you last had sex in order to make sure this medicine is suitable for you. This medicine can be used at any point during your menstrual cycle, apart from if your period is late. If your period is late, or your last period was more than five days late or unusually light or heavy, you should tell your pharmacist, as you may already be pregnant and this medicine will not work.
This medicine might make your next period earlier or later than expected by a few days. If your next period after taking this medicine is more than seven days late, or is abnormal in any way, you should consult your doctor for a pregnancy test.
This medicine will not always prevent a pregnancy. If you do become pregnant after taking this medicine there is a possibility that the pregnancy will be ectopic (ie occuring in the fallopian tubes rather than the womb). For this reason, you should consult your doctor if you experience any sudden or abnormal abdominal pain after taking this medicine, and if your next period is shorter or lighter than your normal period.
The morning after pill does not provide continued contraception to prevent pregnancy after you have taken it. It is recommended that after taking it, you use a barrier method of contraception such as a condom or cap, until your next period comes. This is also recommended even if you are also taking the pill. You should talk ask your doctor, pharmacist or family planning clinic for advice about regular methods of contraception.
This medicine should only be used as an emergency measure. It is not recommended for repeated use, as it is possible that it can disrupt your menstrual cycle.
Use with caution in
Severe malabsorption syndromes, such as Crohn’s disease (as these may prevent the tablet being properly absorbed).
Rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption (Levonelle one step tablets contain lactose).
This medicine is not recommended for women with severely decreased liver function.
Rare hereditary blood disorders called acute porphyrias.
Not to be used in
Known or suspected pregnancy
This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy. If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Pregnancy and breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
This medicine should not be taken by women who are already pregnant. If you think you could be pregnant, if your period is late, or if your last period was more than five days late or unusually light or heavy, you should tell your doctor, as you may already be pregnant. Taking this medicine if you are already pregnant will not stop the pregnancy.
Emergency contraception does not prevent a pregnancy in every instance. If this medicine doesn’t work to prevent a pregnancy, it is not known to have adverse effects on a pregnancy that develops in your womb. However, there is a possibility that a pregnancy could be ectopic after taking the morning after pill, so you should consult your doctor immediately if you think you could be pregnant. Ask your doctor, pharmacist or family planning clinic for more information.
Small amounts of this medicine pass into breast milk. If you need to take this medicine while you are breastfeeding this is not thought to be harmful to the nursing baby. However, you can minimise your baby’s exposure to the medicine by taking the dose immediately after giving a feed. By the time the next feed is due the amount of medicine in the breast milk will then be reduced.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.
Very common (affect more than 1 in 10 people)
Vaginal bleeding after taking the tablet (not related to your normal period).
Common (affect between 1 in 10 and 1 in 100 people)
Delayed start of next menstrual period (consult your doctor if your next period after taking this medicine is more than seven days late).
Menstrual spotting or irregular bleeding.
The side effects listed above may not include all of the side effects reported by the medicine’s manufacturer. For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
How can this medicine affect other medicines?
It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you take this medicine, to make sure that the combination is safe.
The morning after pill may be less effective if you are taking any of the following medicines, because these medicines speed up the breakdown of levonorgestrel by the liver:
protease inhibitors such as ritonavir
the herbal remedy St John’s wort (Hypericum perforatum)
If you are taking any of these medicines regularly, you may be advised to have a copper coil (IUD) fitted as emergency contraception, as this is not affected by the medicines you are taking. An alternative would be to take two Levonelle tablets (ie a total dose of 3mg). This is an unlicensed use of the medicine. You should discuss these options with your doctor, pharmacist or family planning clinic.