Mercilon tablets are a type of hormonal contraception commonly known as 'the pill' or combined oral contraceptive pill. Mercilon tablets contain two active ingredients, ethinylestradiol and desogestrel. These are synthetic versions of the naturally occurring female sex hormones, oestrogen and progesterone. Ethinylestradiol is a synthetic version of oestrogen and desogestrel is a 'third generation' synthetic form of progesterone.
What is Mercilon used for?
Taking the contraceptive pill usually results in lighter, less painful and more regular menstrual bleeding. This means it is sometimes also prescribed for women who have problems with particularly heavy, painful or irregular periods.
How does Mercilon work?
- Mercilon tablets are a type of hormonal contraception commonly known as 'the pill' or combined oral contraceptive pill. Mercilon tablets contain two active ingredients, ethinylestradiol and desogestrel. These are synthetic versions of the naturally occurring female sex hormones, oestrogen and progesterone. Ethinylestradiol is a synthetic version of oestrogen and desogestrel is a 'third generation' synthetic form of progesterone.
- Combined oral contraceptives like Mercilon work by over-riding the normal menstrual cycle. In a woman's normal menstrual cycle, levels of the sex hormones change throughout each month. The hormones cause an egg to be released from the ovaries (ovulation) and prepare the lining of the womb for a possible pregnancy. At the end of each cycle, if the egg has not been fertilised the levels of the hormones fall, causing the womb lining to be shed as a monthly period.
- The daily dose of hormones taken in the pill work mainly by tricking your body into thinking that ovulation has already happened. This prevents an egg from ripening and being released from the ovaries each month.
- The hormones also increase the thickness of the natural mucus at the neck of the womb, which makes it more difficult for sperm to cross from the vagina into the womb and reach an egg. They also change the quality of the womb lining (endometrium), making it less likely that a fertilised egg can implant there.
How do I take Mercilon?
- Mercilon is a monophasic pill. This means that each tablet has the same dose of hormones in it. One tablet is taken every day for 21 days and you then have a seven day break from pill-taking. During your seven day break, the levels of the hormones in your blood drop, which results in a withdrawal bleed that is similar to your normal period. You start the next pack after the seven pill-free days are up, even if you are still bleeding.
- The tablets come in a calendar pack marked with days of the week to help you remember to take a pill every day for three weeks, followed by a week off. You will still be protected against pregnancy in your pill-free week, provided you took all the pills correctly, you start the next packet on time and nothing else happened that could make the pill less effective (eg sickness, diarrhoea, or taking certain other medicines - see below).
- You should try and take your pill at the same time every day; this will help you remember to take it. Each tablet should be swallowed with a drink. They can be taken either with or without food.
When can I start taking it?
- Ideally, you should start taking this pill on day one of your menstrual cycle (the first day of your period). This will protect you from pregnancy immediately and you won't need to use any additional methods of contraception. If necessary, you can also start taking it up to day five of your cycle without needing to use additional contraception when you start. However, if you have a short menstrual cycle (with your period coming every 23 days or less), starting as late as the fifth day of your cycle may not provide you with immediate contraceptive protection. You should talk to your doctor or nurse about this and whether you need to use an additional contraceptive method for the first seven days.
- You can also start taking this pill at any other time in your cycle if your doctor is reasonably sure that you are not pregnant. However, if you start taking this pill at any other time in your cycle, you won't be protected from pregnancy straight away and you will need to use additional contraception, eg condoms (or not have sex) for the first seven days of pill taking.
- If you have given birth and are not breastfeeding, you can start taking this pill on day 21 after the birth. You will be protected against pregnancy immediately and do not need to use extra contraception. If you start taking it later than 21 days after giving birth, you will need to use extra contraception for the first seven days.
- If you are starting this pill immediately after a miscarriage or abortion at under 24 weeks, you will protected against pregnancy immediately. If you start taking it more than seven days after the miscarriage or abortion, you should use extra contraception for the first seven days of pill taking.
What do I do if I miss a pill?
If you forget to take your pill at your usual time, take it as soon as you remember. A missed pill is one that is 24 hours or more late. If you miss a pill, follow the instructions below.
One pill missed
- If you forget to take ONE pill, or start your new pack one day late, you should take the pill you missed as soon as possible, even if this means taking two pills at the same time. Then continue taking the rest of the pack as normal. You will still be protected against pregnancy and you don't need to use extra contraception.
Two or more pills missed
- If you forget to take TWO or more pills, or start your new pack two or more days late, you won't be protected against pregnancy. You should take the last pill you missed as soon as possible, even if this means taking two pills at the same time. Leave out the other missed ones. Then continue to take your pills, one every day, as normal. You should either not have sex, or use an extra barrier method of contraception, eg condoms, for the next seven days.
If there are fewer than seven pills left in your pack after your last missed pill, you should finish the pack and then start a new pack straight away without a break. This means skipping your pill-free week.
What if I have vomiting or diarrhoea?
- If you vomit within two hours of taking a pill, it may not have been fully absorbed into your bloodstream. You should take another pill as soon as you feel well enough and take your next pill at your usual time. You should still be protected from pregnancy. However, if vomiting continues for more than 24 hours, this may make your pill less effective. You should keep taking your pill at your normal time, but treat each day that you have vomiting as if you had forgotten to take a pill and follow the instructions under "what do I do if I miss a pill" above.
- If you have very severe diarrhoea for more than 24 hours, this may make your pill less effective. You should keep taking your pill at your normal time, but treat each day that you have severe diarrhoea as if you had forgotten to take a pill and follow the instructions under "what do I do if I miss a pill" above.
Mercilon should not be used by
- Women who are breastfeeding (the combined pill shouldn't be taken until weaning or for six months after birth - see below for more information).
- Women who have ever had a blood clot in a vein (venous thromboembolism), eg in the leg (deep vein thrombosis) or in the lungs (pulmonary embolism).
- Women with a parent, brother or sister who has had a blood clot in a vein (venous thromboembolism), eg in the leg (deep vein thrombosis) or in the lungs (pulmonary embolism) before the age of 45.
- Women with blood disorders that increase the risk of blood clots in the veins, eg antiphospholipid syndrome or factor V Leiden.
- Women having sclerosing treatment for varicose veins.
- Women with two or more other risk factors for getting a blood clot in a vein, eg obesity, smoking, long-term immobility.
- Women who have ever had a heart attack, stroke or mini-stroke caused by a blood clot in an artery.
- Women with angina, heart valve disease or an irregular heartbeat called atrial fibrillation.
- Women with moderate to severe high blood pressure (hypertension).
- Women who smoke more than 40 cigarettes per day.
- Women over 50 years of age.
- Women over 35 years of age who smoke more than 15 cigarettes per day.
- Women with severe diabetes, eg with complications affecting the eyes, kidneys or nerves.
- Women with two or more other risk factors for getting a blood clot in an artery, eg family history of heart attack or stroke before the age of 45 (parent, brother or sister), diabetes, high blood pressure, smoking, high cholesterol levels, obesity, migraines.
- Women who get migraines with aura, severe migraines regularly lasting over 72 hours despite treatment, or migraines that are treated with ergot derivatives.
- Women with breast cancer or a history of breast cancer (although the pill can be used if you have been free of cancer for five years and you don't want to use non-hormonal methods of contraception).
- Women with abnormal vaginal bleeding where the cause is not known.
- Women with a long-term condition called systemic lupus erythematosus (SLE).
- Women with a history of excess of urea in the blood, causing damaged red blood cells (haemolytic uraemic syndrome).
- Women with active liver disease, eg liver cancer, hepatitis.
- Women with a history of liver disease when liver function has not returned to normal.
- Women with disorders of bile excretion that cause jaundice (eg Dubin-Johnson or Rotor syndrome).
- Women with gallstones.
- Women with a history of jaundice, severe itching, hearing disorder called otosclerosis, or rash called pemphigoid gestationis during a previous pregnancy, or previous use of sex hormones.
- Hereditary blood disorders known as porphyrias.
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.
Mercilon should be used with caution by
- Women aged over 35 years.
- Women whose parent, brother or sister had a heart attack or stroke caused by a blood clot before the age of 45.
- Women who are obese.
- Women with diabetes mellitus.
- Women with high blood pressure (hypertension).
- Women with heart failure.
- Women who use a wheelchair.
- Women with a history of inflammation of a vein caused by a superficial blood clot (thrombophlebitis).
- Women with anaemia caused by a hereditary blood disorder where abnormal haemoglobin is produced (sickle cell anaemia).
- Women with a history of severe depression, especially if this was caused by taking the pill in the past.
- Women with a history of migraines (see above).
- Women with inflammatory bowel disease, eg Crohn's disease or ulcerative colitis.
- Women with a personal or family history of raised levels of fats called triglycerides in the blood (hypertriglyceridaemia).
- Women with raised levels of the hormone prolactin in their blood (hyperprolactinaemia).
- Women with an undiagnosed breast lump or gene mutations that are associated with breast cancer, eg BRCA1.
- Women with a history of irregular brown patches appearing on the skin, usually of the face, during pregnancy or previous use of a contraceptive pill (chloasma). Women with a tendency to this condition should minimise their exposure to the sun or UV light while taking this contraceptive.
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 is used to prevent pregnancy and should not be taken during pregnancy. However, if the pill fails or you miss pills and you do get pregnant while taking it, there is no evidence to suggest that the pills you have already taken will harm the baby. If you think you could be pregnant while taking this pill you should stop taking it and consult your doctor immediately.
- The hormones in this pill can reduce the production of breast milk. For this reason, it is not recommended for women who are breastfeeding. It should not be used until weaning, or at least six months after the birth. Other methods of contraception are more suitable for women who are breastfeeding. Ask your doctor for advice.
Possible side effects of Mercilon
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. See also the warnings above. Just because a side effect is stated here does not mean that all people using this medicine will experience that or any side effect.
- Nausea and vomiting.
- Abdominal pain.
- Breast tenderness and enlargement.
- Weight changes.
- Retention of water in the body tissues (fluid retention).
- Vaginal thrush (candidiasis).
- Change in menstrual bleeding, usually lighter periods or sometimes stopping of periods.
- Menstrual spotting or breakthrough bleeding.
- Decreased sex drive.
- Rise in blood pressure.
- Skin reactions.
- Irregular brown patches on the skin, usually of the face (chloasma).
- Steepening of corneal curvature, which may make contact lenses uncomfortable.
- Disturbance in liver function.
- Blood clots in the blood vessels (eg, DVT, pulmonary embolism, heart attack, stroke - see warnings above).
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.
If you think you have experienced a side effect from a medicine or vaccine you should check the patient information leaflet. This lists the known side effects and what to do if you get them. You can also get advice from your doctor, nurse or pharmacist. If they think it''s necessary they'll report it for you.
How can Mercilon 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 start taking this contraceptive. Similarly, check with your doctor or pharmacist before taking any new medicines while using this one, to make sure that the combination is safe.
The following medicines speed up the breakdown of the hormones in this contraceptive by the liver, which makes it less effective at preventing pregnancy:
- perampanel (12mg)
- the herbal remedy St John's wort (Hypericum perforatum)
If you regularly take any of these medicines they are likely to make this contraceptive ineffective at preventing pregnancy. It is important that you talk to your doctor about this. Your doctor will usually recommend that you use a different form of contraception altogether. However, if you want to use the pill (and you are not taking rifampicin or rifabutin - see below), your doctor can prescribe you an additional pill to take in combination with this one, which would give you a higher dose of hormones. (This is unlicensed). If you do this, your doctor will also ask you to take three packets back to back without a break, have only a four day pill-free break, then take three packets back to back again. You repeat this for as long as you are taking the other medicine and for a further four weeks after stopping it. (This is called tricycling and is also unlicensed.) The purpose of this is to reduce the number and duration of hormone free periods in which ovulation could happen and thus minimise the chances of the pill failing.
If you are prescribed a short course (up to two months) of any of the above medicines they will also make this contraceptive less effective. Your doctor may recommend that you temporarily use a different form of contraception to prevent pregnancy. However, if you want to keep taking this pill, your doctor will probably advise you to take three packets back to back without a break, then have only a four day pill-free break. (This is called tricycling and is unlicensed.) You will also need to use an additional method of contraception (eg condoms) while you are doing this, for as long as you take the liver-affecting medicine and for at least four weeks after stopping it. Alternatively, your doctor could prescribe an additional pill to take in combination with this one, as above. Discuss your options with your doctor.
If you are prescribed rifampicin or rifabutin, an alternative method of contraception will always be recommended, because these two antibiotics make the pill so ineffective.
In the past, if you were prescribed an antibiotic other than rifampicin or rifabutin (eg amoxicillin, erythromycin, doxycycline) while taking the pill, the advice used to be that you use an extra method of contraception (eg condoms) while you were taking the antibiotic and for seven days after finishing the course. However, this advice has now changed. You no longer need to use an extra method of contraception with the pill while you take a course of antibiotics. This change in advice comes because to date there is no evidence to prove that antibiotics (other than rifampicin or rifabutin) affect the pill. This is the latest guidance from the Faculty of Sexual & Reproductive Healthcare. However, if you experience vomiting or diarrhoea as a result of taking an antibiotic you should follow the instructions for vomiting and diarrhoea described in the warning section above.
The emergency contraceptive ulipristal (Ellaone) has the potential to make the pill less effective. If you take Ellaone as an emergency contraceptive while you are taking Mercilon, you should use an additional method of contraception such as condoms for 14 days after you take it.
The antifungal medicine griseofulvin may make the pill less effective. You should use an extra method of contraception both during treatment with griseofulvin and for one month after stopping treatment.
The weight loss medicine orlistat (bought without a prescription as Alli and prescribed as Xenical) can cause severe diarrhoea. If you take either of these medicines while taking Mercilon and get diarrhoea that lasts for more than 24 hours, you should follow the instructions for missed pills described above.
If you are taking the cholesterol-lowering medicine colesevelam in combination with the pill, it must be taken at least four hours after taking your pill, as otherwise it can reduce the absorption of the pill from the gut and make it less effective.
The pill may oppose the blood sugar lowering effect of medicines for diabetes. If you have diabetes you should monitor your blood sugar and seek advice from your doctor or pharmacist if your blood sugar control seems to be altered after starting this contraceptive.
The pill may oppose the effect of medicines used to lower high blood pressure. Your blood pressure will usually be checked periodically while you are taking the pill, but this is particularly important if you are also taking medicines for high blood pressure.
The pill may also oppose the fluid-losing effect of diuretic medicines.
If you have an underactive thyroid gland (hypothyroidism) you may need an increased dose of your thyroid hormones while taking the pill. Your thyroid hormone levels should be regularly checked.
The pill may decrease the amount of the antiepileptic medicine lamotrigine in the blood. As this could increase the risk of seizures coming back or getting worse, the pill may not be recommended for women who take lamotrigine on its own for epilepsy.
The pill may increase the blood levels of the following medicines and this could possibly increase the risk of their side effects:
- selegiline (should be avoided in combination with the pill)
- theophylline (reduced dose of theophylline may be needed)