- Take daily for 21 days, with a 7-day break (alternatives possible)
- Lower dose of oestrogen can cause fewer side effects
- Needs yearly blood pressure and weight checks
How to take Mercilon
Most women choose to take 1 pill daily for 21 days, then have a 4 or 7-day break before starting the next pack. During this break you’re likely to have a withdrawal bleed. This is like a period but isn’t one.
You can also take Mercilon as follows:
- Tricycling: Take 1 pill daily for 9 weeks without a break. After 9 weeks (3 packs of pills) take a 4 or 7 day break and then start the cycle again.
- Continuous use: Take 1 pill daily without a break.
- Flexible extended use: Take 1 pill daily for at least 21 days. If you get bleeding that’s unacceptable to you, take a 4-day break. On the fifth day start taking the pill daily again and don’t have another break for at least 21 days.
How does Mercilon work?
The hormones in Mercilon (desogestrel and ethinylestradiol) prevent your ovaries from releasing an egg (ovulation). They also make it difficult for sperm to reach an egg, or for an egg to implant itself in the lining of the womb.
How effective is Mercilon?
When taken correctly, Mercilon is 99% effective in preventing pregnancy. If it’s not always taken correctly roughly 9 out of 100 women will get pregnant.
If you are vomiting or have severe diarrhoea you may not be protected against pregnancy. If this happens, continue to take the pill as usual but use a condom whilst you're ill. If this continues for more than 24 hours you should follow the same steps as a missed pill.
Please note – you should only start Mercilon if you’re sure you’re not pregnant.
How long after taking Mercilon are you protected?
If you start using Mercilon on days 1-5 of your period, you should be protected from pregnancy immediately, provided you don’t have a short or irregular menstrual cycle.
If you start after day 1 and have short/irregular menstrual cycle you’ll need to use condoms for 7 days if you have sex. Your clinician will be able to advise if you need to use extra contraception in the first 7 days if you have sex.
What are the side effects?
Many women do not experience any side effects, however some experience more irregular bleeding with a low-dose pill. This usually settles in a few months. Other side effects can include headaches, feeling sick, breast discomfort, or mood swings. Rarely, some women develop blood clots. This pill carries a slightly higher risk of blood clots than others. If you have any concerns, send us a message via your Patient Record.
For full information on side effects and correct use, see the patient information leaflet. If any side effects concern you, contact us via your Patient Record.
What should I do if I miss the pill?
This depends on when and how many pills are missed. Missing one pill, at any time, does not compromise contraception. Missing two or more pills or starting a new pack late might affect your contraceptive cover.
Up to 48hrs since your last pill – take your next pill as soon as you remember and continue the rest of the pack as usual. This might mean you need to take 2 pills on 1 day.
More than 48hrs – this depends on when you last took your pill and where you are in your pill packet. Please check the patient information leaflet for further information.
Is Mercilon safe to use whilst breastfeeding?
It is not advised to start any combined contraceptive pill, like Mercilon, until 6 weeks after birth, if you’re breastfeeding.
Will Mercilon affect my weight?
There is no evidence to suggest that Mercilon, a combined contraceptive pill, will affect your weight. You may find your weight changes throughout your cycle due to fluid retention and other reasons not related to the pill.
Can Mercilon stop periods?
If you take 2 packs of Mercilon back-to-back, you can avoid having a period.
Can I buy Mercilon online?
You can request and pay for a Mercilon prescription online. As this pill is a prescription-only medication, even if you are using an online service, you will need a prescription from a clinician before you can buy the treatment.
With all combined contraceptive pills, we will need to know your height, weight and blood pressure to prescribe safely. You can fill this out during the consultation. If you don’t know your blood pressure, don’t worry, you can have this checked in your local LloydsPharmacy.
How do I switch to Mercilon from a different pill?
If you would like to switch your contraceptive pill, contact us via your Patient record or get an appointment with your GP to discuss the change. If you are changing to a new pill you would be advised to have no break between the packs and you may have to use other contraceptive methods during the changeover.
Important information about Mercilon
If you’ve already bought your pill from us, you can request a further 3, 6 or 12-month supply from your Patient Record, if you're medically suitable. If you want to change your pill, please send us a message via your Patient Record.
Combined contraceptives can cause your blood pressure to rise, which can be dangerous. Your blood pressure needs checking before starting any combined contraceptive, then once a year after that. If you’ve had your blood pressure checked recently, or checked it yourself using a home blood pressure monitor, you can give us this information as part of your consultation. Alternatively, you can have these checked when you pick up your prescription in your local LloydsPharmacy.
Safety: taking other medicines
You should be able to take Mercilon alongside other medicines. However, it is important that you let us know which prescription, over-the-counter medicines and recreational drugs you are taking so that we can prescribe Mercilon safely.
We offer a range of contraceptives, including NuvaRing, Evra Patch, combined pills, low-dose pills and mini pills. View all our contraception options.
Condoms are an effective form of contraception and protect against STIs.
There are also long-acting contraceptives available through your GP or family planning clinic, including implants, the coil and injectable contraception.