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What is Mercilon?

Mercilon is a combined oral contraceptive pill, known colloquially as “the pill.” Contraceptives stop you from becoming pregnant. There are two types - barrier methods, such as condoms or vaginal films, and hormonal methods, which include tablets, patches, implants or injections.

Mercilon is a hormonal contraceptive. It is a pill that you swallow every day. When taken correctly, it is one of the most reliable reversible methods of contraception, and is up to 99% effective at preventing pregnancy.

Mercilon is available on prescription from your doctor or pharmacist. Alternatively, we can prescribe it to you following a brief online consultation. Contact us to find out more.

The active ingredients in Mercilon are desogestrel and ethinylestradiol. For more information about Mercilon, consult the patient information leaflet.

How it works

Mercilon, like other combined hormonal contraceptive pills, releases an oestrogen and progestogen into your bloodstream. These female sex hormones are the same as the hormones produced by your body, and they work in several different ways to prevent pregnancy. It stops your ovaries from releasing an egg every month (ovulation,) it thickens cervical mucus to make it difficult for sperm to reaching an egg and it also thins the lining of the womb to prevent an egg from implanting itself.

Mercilon can take up to 7 days to become effective, depending on where you are in your menstrual cycle when you take it. During this time, you should use additional methods of contraception, such as condoms.

Before you take it

You should not take Mercilon if you are allergic to either of the active ingredients in the medication, desogestrel and ethinyl estradiol, or any of the other inactive ingredients. Speak with your doctor who will be able to recommend an alternative method of contraception.

You must not take Mercilon alongside any other form of hormonal contraception, as taking more than one type of contraceptive pill can cause you to experience high blood pressure. One type of hormonal contraceptive is sufficient to prevent pregnancy. It is safe to combine use of a contraceptive pill with barrier methods of contraception, such as a vaginal film or a condom.

You should not use Mercilon when you are pregnant. If you are unsure whether you are pregnant before taking Mercilon, take a pregnancy test. In the unlikely event that you become pregnant while taking the pill, stop taking Mercilon as soon as possible, and visit your doctor. You should also not use Mercilon while breastfeeding.

Speak with your doctor if you have ever experienced a heart attack, stroke, liver or kidney problems before taking Mercilon. It may be unsuitable for you.

Mercilon can increase the risk that you experience a blood clot or thrombosis. This risk is very small, but is slightly higher than in women who do not take a form of combined hormonal contraception. A blood clot can cause deep vein thrombosis or a pulmonary embolism, and in some cases can be fatal. You should speak with your doctor to discuss this if it concerns you.

The risk of a blood clot is made higher if you are severely overweight or obese, if you smoke, or if you are over 35 or have experienced a blood clot before. Speak to your doctor before you start taking Mercilon if this applies to you.

Mercilon will not protect you from sexual health problems, such as sexually transmitted diseases. No combined contraceptive pill will do this. You must use a condom or other barrier method of contraception if you wish to protect yourself from sexually transmitted diseases.

Mercilon may also increase your risk of developing breast or cervical cancer. Again, this risk is minimal, but while taking Mercilon your doctor may wish to examine you more regularly. This may include examinations of your breasts or performing a cervical smear test. You should monitor your own breasts for abnormalities, and report anything unusual to your doctor.

If you take emergency contraception such as the morning after pill while also taking Mercilon, it may not be as effective. Speak with your doctor if you require emergency contraception while taking Mercilon.

You should not take Mercilon and speak to your doctor to discuss an alternative method of contraception if any of the following apply to you:

  • You have ulcerative colitis
  • You have ever experienced blood clotting or thrombosis
  • If you have ever had a heart attack or a stroke
  • If you have recently had severe liver disease
  • If you have ever had a liver tumour
  • If you have experienced unexplained vaginal bleeding
  • You have cancer that is affected by sex hormones - breast cancer, womb cancer or ovarian cancer

Some medicines may interact with Mercilon. Speak with your doctor if you are taking any of the following:

  • Anticonvulsant drugs to treat epilepsy (carbamazepine, oxcarbazepine)
  • Tuberculosis medication such as rifampicin
  • HIV treatment (ritonavir, efavirenz)
  • Antidepressants (citalopram, fluoxetine, St John’s Wort)
  • Medication to treat infectious diseases such as griseofulvin)
  • High blood pressure medication (bosentan)

This is not an exhaustive list of interactions or warnings. For a full list, consult the patient information leaflet, or speak with your doctor.

Dosage Instructions

You should always take Mercilon exactly as your doctor or pharmacist has prescribed. Never exceed the stated dose. If you are unsure of how to take your medication, you must go to your doctor to ask for clarification.

Mercilon comes as a calendar pack of 21 pills. Each pill is marked with a day of the week. You should take one pill every day for 21 days, then have a seven day break, during which you will experience a withdrawal bleed. You will be protected from pregnancy during this break, providing you have taken all your pills correctly, and you start your next pack on time.

You must take your pills at the same time each day. As long as you are taking Mercilon correctly, you will always start a new pack on the same day every 4 weeks.

If you’re a new user of Mercilon, you should take your pill on the first day of your next period. You will have contraceptive protection immediately if you take it within the first 5 days of your next period.

Store Mercilon in a cool, dry place, away from heat and moisture. Keep it out of the sight and reach of children and pets.

Common Side Effects of Mercilon

Like all medications, Mercilon can cause side effects. They are usually mild to moderate in nature and should go away on their own as your body becomes used to the medication. However, if they persist, or they concern you, speak with your doctor. Symptoms include:

  • Headache
  • Weight Gain
  • Painful or tender breasts
  • Depression or mood changes
  • Abdominal pain

Mercilon may also cause more serious side effects. These are less common, but if you experience them, visit your doctor. They include:

  • Migraine
  • Fluid retention
  • Decreased sexual interest
  • Vomiting
  • Diarrhoea
  • Breast enlargement

Mercilon may also cause a severe allergic reaction in some women. This is extremely rare, but an allergic reaction of any kind is an emergency. If you believe you are experiencing an allergic reaction, seek medical advice immediately. Symptoms can include:

  • Hives
  • Trouble breathing or speaking
  • Wheezing
  • Tightness in the chest or throat
  • Skin rash, including redness, itchines, blistering and peeling

This is not an exhaustive list of side effects. For a full list, consult your doctor, or read the patient information leaflet.

Frequently Asked Questions (FAQs)

What happens if I become pregnant?

It is highly unlikely that you will become pregnant when taking Mercilon. When taken correctly it is up to 99% effective at preventing pregnancy. Most unwanted pregnancies that occur while taking Mercilon are as a result of a dosing mistake, such as taking tablets at the wrong time, or missing tablets. If you believe you are pregnant, take a pregnancy test and go to your doctor.

What happens if I vomit or have diarrhoea?

Mercilon is absorbed into the bloodstream through the lining of the stomach. If you vomit or have diarrhoea within 2 hours of taking Mercilon, it may not have been absorbed properly through the stomach. Take another pill when you feel well enough. If your illness causes you to miss more than one pill, you should use additional contraception for the next 7 days.

What happens if I miss a dose?

In order for Mercilon to work properly it must be taken every day as directed. If you miss a pill, and you remember within 24 hours, simply take the next pill in your pack - your pregnancy protection won’t be affected. If it has been more than 24 hours, take your missed pills, but ensure you use additional contraception for the next 7 days. If you have had sex during this period, you may not have been protected from pregnancy and may need emergency contraception.

What happens if I take too much?

An overdose of a combined pill such as Mercilon is unlikely to harm you. However, it may cause unpleasant symptoms, such as vaginal bleeding, nausea or trembling. Speak with your doctor if you believe you have overdosed on Mercilon.
More Information
Dosage Instructions Please see medicine label for the dosage instructions.