Prices

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About Mercilon

What is Mercilon?

Mercilon is a combined oral contraceptive (COC) pill brand available on prescription only.

Each pill contains the following hormones, similar to natural hormones produced by the ovaries:

• 20mcg ethinylestradiol (estrogen)
• 150mcg desogestrel (progesterone)

Because Mercilon contains only 20 mcg ethinylestradiol, it is regarded as a low dose pill.

As Mercilon contains desogestrel it is called a third generation pill.

Each pack of Mercilon contains 21 pills.

Which pills are the same as Mercilon?

Gedarel 20/150 is the only other pill brand with exactly the same active hormonal ingredients. There should be no difference in the efficacy of Mercilon or Gedarel 20/150.

These pills are all medically the same. There should be no difference in their efficacy.

Because Mercilon and Gedarel 20/150 both contain only 20mcg ethinylestradiol, they are regarded as low dose pill.

30-35mcg of ethinylestradiol, as in Marvelon and Gedarel 30/150, is a standard pill dose. Mercilon and Gedarel 20/150 are low dose options.

Which pills are similar to Mercilon?

Marvelon and Gedarel 30/150 contain the same hormonal constituents as Mercilon and Gedarel 20/150. They all contain desogestrel 150 mcg. However Marvelon and Gedarel 30/150 contain a higher dose of ethinylestradiol: 30mcg.

Are there other 20mcg pills?

A full list of 20mcg estrogen pills is displayed below:

• Loestrin 20
• Mercilon
• Gedarel 20/150
• Femodette
• Millinette 20/75
• Sunya 20/75

In terms of their progesterone content, Loestrin 20 contains levonorgestrel, Mercilon and Gedarel 20/150 contain desogestrel, and Femodette, Millinette 20/75 and Sunya 20/75 all contain gestodene. For more information see Why choose 20mcg contraceptive pill instead of 30mcg pill?

How does Mercilon work as a contraceptive pill?

One pill is taken every day, for 21 consecutive days. By taking a small amount of hormone every day, your ovaries temporarily shut down, and this stops you producing an egg – the pill prevents ovulation.

During the 7 days that you do not take a pill you will usually get a withdrawal bleed, similar to a period. When you finish a pack after 28 days you should start another pack the next day whether or not you are still bleeding.

Mercilon also causes changes to the lining of the womb such that if you did ovulate, a fertilised egg would not implant. Cervical mucus also becomes thick and hostile to sperm.

How effective is Mercilon at stopping me becoming pregnant?

The combined pill is 99% effective at preventing a pregnancy when taken correctly.

• With 'perfect use' (taken as directed at the same time of day): if 100 women took the pill for a year there would be 0.3 pregnancies.
• With 'typical use': if 100 women took the pill for a year there would be 8-9 pregnancies.

See NHS: How effective is contraception at preventing pregnancy? - contraceptive-pill.

It's hard to remember to take your pill at the same time every day. You do need to follow the pill rules very carefully. Setting a daily reminder on your phone is advisable.

20mcg combined pills contain 30% less estrogen than other combined pills. However these are still a recommended and reliable form of contraception.

It has been noted that over the past 50 years, as the dose of hormones in the pill has been reduced, pill failures in clinical trials have gone up. 20mcg pills do give safe reliable contraception, but for some women, the added safety of a standard 30mcg pill, may be preferable.

For more information see Why choose 20mcg contraceptive pill instead of 30mcg pill? and Can I trust my contraceptive?

There are 15 methods of contraception, the pill is just one of them. Do consider your options and make the best contraceptive choice for you.

What are the most likely side effects from Mercilon?

Side effects on the pill are said to be common, but whether these symptoms are really due to the pill, is uncertain.

The most common side effects are nausea, acne, headache, breast tenderness, bloating, and irregular bleeding.

Mercilon is called a third generation pill. It contains the progesterone desogestrel, which is slightly less likely (compared to older second generation progesterones e.g. levonorgestrel/norethisterone) to cause androgenic (male type) side effects. Medical studies have had conflicting results to substantiate this. Women's response to hormones is very individual. However if side effects on second generation pills do not settle and become a problem, a switch to a third generation pill e.g. Mercilon is often advocated.

There is no firm evidence that the pill has a significant effect on weight gain.

What are the risks of Mercilon?

Serious side effects - adverse events - are rare. You can only be prescribed the pill if you are medically suitable, and need regular pill checks with a doctor/nurse to continue.

The most serious adverse events on the combined pill are:

• Thrombosis – Deep Vein Thrombosis (DVT), Pulmonary Embolus (PE) - a blood clot - approximate risk is 6-12 in 1000 users/year. This is slightly higher than the risk of a blood clot on a pill containing levonorgestrel e.g. Microgynon 30, or norethisterone e.g. Loestrin 20/Loestrin 30.
• Stroke, or a Transient Ischaemic Attack (TIA) – a mini-stroke - is still very rare in COC pill users. Regular blood pressure checks are needed, as stroke is associated with high blood pressure.
• Migraine with aura is a contraindication to the combined pill.
• Heart disease, angina, heart attack – the increased risk in combined pill users occurs - almost exclusively - only in smokers.
• Breast cancer. A 24% increase in risk compared to non-COC pill takers, but because the breast cancer risk is very low in young women, a 24% increase in risk only results in very small numbers of extra cases.
• Cervical cancer - the risk is increased after 5 years of pill use. However this is not a reason not to take the pill. Pill users need to be encouraged to attend for cervical smears.

See below for when side effects are an emergency.

It is very important to have annual pill checks to make sure the pill continues to be safe for you to take.

Third generation pills e.g. Marvelon, and Mercilon have a slightly higher risk of thrombosis (a blood clot) than second generation pills (e.g. Microgynon 30 or Loestrin 30). The overall risk of a thrombosis for women using:

• a second generation pill e.g. Microgynon 30 or Loestrin 20 is 5-7 in 10,000 users per year
• a third generation pill e.g. Marvelon or Mercilon is 6-12 in 10,000 users per year.

What are the benefits of Mercilon?

• Mercilon has been in use in the UK since 1986, and is commonly prescribed.
• You can stop and start your pills, including Mercilon, as you wish, without having to see a doctor/nurse.
• Taking a contraceptive pill, such as Mercilon, is convenient, and it works very effectively if taken correctly.
• There are non-contraceptive benefits with all combined pills - this includes Mercilon e.g. improved acne, lighter/less painful periods. You can also run packs together – extended use regimes - and avoid having periods altogether - see How to take your contraceptive pill. This is also possible with 20mcg pills. There is some medical evidence that because Mercilon contains desogestrel, which is a more modern progesterone, there may be less in the way of androgenic (male type) side effects.
• Some serious diseases e.g. ovarian cancer, are dramatically reduced by taking a combined pill such as Mercilon.
• Mercilon, like other combined pills, is quickly reversible and fertility returns immediately on stopping.
• Mercilon is a low dose pill (30-35mcg ethinylestradiol is the estrogen dose in a standard dose pill).

What are the disadvantages of Mercilon?

• Mercilon has to be taken correctly. This can be difficult especially with a busy lifestyle. Typical use failure rates are high, around 8-9%. Many women are now opting for Long Acting Reversible Contraception (LARC).
• If you have side effects you may need to try several different pill brands until you find the one most suited to you.
• There are small risks such as an increased risk of thrombosis, stroke, TIA, and heart attack – although these are very uncommon.
• You need a prescription to obtain the pill - a consultation with a health professional is required to ensure eligibility for use.

Who should not take Mercilon?

The combined pill is not suitable for you if you have any of the following:

• A current or past history of thrombosis - a DVT/PE (a blood clot), or if you have a known genetic clotting disorder e.g. Factor V Leiden mutation.
• A current or past history of heart disease, angina, heart attack, stroke, or mini stroke (Transient Ischaemic Attack – TIA).
• A current or past history of breast cancer, an undiagnosed breast lump, or if you carry a breast cancer gene.
• Aged 35 and over who smoke.
• A past history of migraine with aura.
• High blood pressure - see BHF - Contraception and a heart condition.
• Hypercholesterolaemia (high cholestrol).
• Diabetes with complications – such as eye disease (retinopathy) or kidney disease.
• Obesity - BMI greater than 35.
• Liver disease.
• Breast feeding, or not breast feeding and less than 3 weeks following childbirth - see Sexwise: Contraceptive choices after you've had a baby.

This list is not exhaustive. Your doctor/nurse can advise you further. See also NHS: Who can use the combined pill.

Why should I choose Mercilon?

Mercilon has been licensed in the UK since 1986, so there is a lot of clinical experience with its use.

Contraceptive pills contain different combinations of hormones. There is a wide variety of different pills, which is advantageous because women vary enormously in their response to hormones. If one pill is not suitable, it is likely you will find another which will suit you better.

Some authorities such as the MRHA/FSRH, have stated that pills which contain levonorgestrel, such as Microgynon, may be the safest choice. But also that if Microgynon is not suitable all currently available pills are safe.

The risk of a blood clot (thrombosis) on Mercilon is 6-12 in 10,000 women per year of use.

For more information see How one doctor recommends a contraceptive pill.

How should I take Mercilon?

Read our detailed guide on How to take your contraceptive pill.

What if I miss pills on Mercilon?

If you forget or miss a pill, you must follow the missed pill rules.

You may need emergency contraception ('the Morning After' pill) and should make an urgent appointment with your GP/practice nurse or visit a local Sexual Health Clinic.

Dr Fox provides standby Morning After pill, ready for when it may be needed.

Do not stop taking your pills - keep going and get prompt help/advice.

Which medicines interact with Mercilon?

The most common interactions are listed below.

• Antibiotics - enzyme inducing antibiotics e.g. rifabutin and rifampicin will interact (but not other commonly used antibiotics).
• Antifungals - griseofulvin is also an enzyme inducer.
• Antivirals - ritonavir, nelfinavir, and nevirapine.
• Anticonvulsants - barbiturates (including phenobarbitone) phenytoin, primidone, carbemazepine, oxcarbazepine, and topiramate. Lamotrigine is not recommended.
• Ulipristal acetate (UPA) - as a progesterone receptor blocker, if used with the combined pill, it could prevent the pill from working. If you take the emergency contraceptive ellaOne, while on the combined pill, do not have unprotected sex for 14 days (16 days for Qlaira).

More detailed medicines interaction information from clinical studies.

When would side effects of taking Mercilon become an emergency?

Seek help immediately (telephone 999 or visit A&E) if you develop:

• Acute chest pain - it may hurt to breathe in, or cough.
• Cough, breathlessness, coughing up blood.
• Feeling dizzy, confusion, collapse.
• A swelling of the lower leg.
• Acute allergy (anaphylaxis) e.g. swelling of the lips, face, or tongue
• Heavy bleeding/severe pelvic pain. If you have heavy bleeding on Mercilon, consider the possibility of pregnancy. This could be due to miscarriage or ectopic pregnancy and would require urgent medical attention.