Co-cyprindiol (Dianette)

How does it work?

Dianette tablets contain two active ingredients, cyproterone acetate and ethinylestradiol. This combination of medicines is also known as co-cyprindiol. (NB. Co-cyprindiol tablets are also available without a brand name, ie as the generic medicine.)

Cyproterone acetate is a type of medicine called an anti-androgen. Androgens are male hormones and are produced by women as well as men. They are responsible for stimulating the growth of the skin, including the sebaceous glands that produce oil (sebum), and the hair that grows from the skin. However, if your body produces too much androgen, or if your skin is particularly sensitive to the effects of androgens, the sebaceous glands may produce too much sebum. This can cause the sebaceous glands to become blocked, resulting in infection, inflammation and acne spots. The androgens may also cause excessive growth of the hair on the face and body - a condition known as hirsutism. Both these problems are common in women with polycystic ovary syndrome (PCOS).

Cyproterone acetate is used to prevent these actions of the androgens. It works by blocking the receptors in the body that the androgens normally work on. This means that the androgens can no longer affect the skin or the hair and acne and hirsutism can improve. Cyproterone acetate also decreases the production of androgens by the ovaries, so that there are less of these male hormones circulating.

You should notice that your skin becomes less greasy within a few weeks of treatment with this medicine, but it may take a few months of treatment before you see a definite improvement in your acne or excessive hair growth.

This medicine is also an effective combined oral contraceptive pill. Cyproterone acetate is a progestogen derivative, and the other ingredient, ethinylestradiol, is a synthetic version of the naturally-occurring female hormone, oestrogen. The medicine works as a contraceptive by preventing the ripening and release of eggs from the ovaries, as well as increasing the thickness of the cervical mucus, which makes it more difficult for sperm to cross from the vagina into the womb. It also changes the lining of the womb so that it is less suitable for any fertilised eggs to successfully implant in.

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).

This medicine is as effective a contraceptive as any other combined hormonal contraceptive, but it should not be used solely for this purpose. It is used to treat severe acne and hirsutism in women and has the advantage of also providing contraception. This means you do not need to use any other method of contraception while you are using this medicine, unless you miss a pill, have a stomach upset, or are prescribed certain other medicines as well. See below for more information about all of these scenarios.

What is it used for?

  • Severe acne in women that has not responded to treatment with oral antibiotics.
  • Abnormal hair growth in women as a result of excessive production of male sex hormones (hirsutism).
  • This medicine will also provide contraception for women taking it for acne or hirsutism, but it should not be used solely as a contraceptive.

It can take a few months of treatment before your acne or hirsutism has completely cleared up and it is recommended that you stop using this medicine three to four months after your skin has got better, rather than use it continuously just for contraception. If your acne or hirsutism flares up again, you can take repeat courses.

What do I do if I miss a pill?

You should try and take your pill at the same time every day to help you remember to take it. This is particularly important if you are relying on this medicine for contraception.

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, 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, forget the other missed ones and 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 you had unprotected sex in the seven days before you missed pills, you may need emergency contraception (the morning after pill). Ask for medical advice.

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.

If there are seven or more pills left in your pack after your last missed pill, you should finish the pack and have your seven day break as usual before starting the next pack.

If you are confused about any of this, you can get individual advice for your circumstances from your doctor, pharmacist, local family planning clinic, or by calling the fpa helpline on 0845 122 8690.


  • 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.
  • This pill will not protect you against sexually transmitted infections, so you may still need to use condoms as well.
  • Women using this contraceptive for the first time may experience menstrual irregularities such as spotting, breakthrough bleeding or missed periods. Consult your doctor if any breakthrough bleeding persists. Your periods may become infrequent or stop after you stop taking this medicine.
  • If you do not have a withdrawal bleed during your pill-free week, you should do a pregnancy test or consult your doctor. This medicine should not be taken during pregnancy, so it is important that you do not start your next pack until you are certain you are not pregnant. In the meantime, you should use a condom or a cap plus spermicide if you have sex.
  • It is important to be aware that, compared with women who do not use these contraceptives, women taking combined pills appear to have a small increase in the risk of developing a blood clot in a vein, eg in the leg (deep vein thrombosis) or in the lungs (pulmonary embolism), or a blood clot in an artery, eg causing a stroke or a heart attack. This risk is greater in certain groups of women, particularly smokers and women who are obese - see cautions and not to be used in below). The risk of blood clots in the veins is slightly greater with this pill than with other pills. However, pregnancy carries a much higher risk of blood clots than any pill. The potential risks must be weighed against the potential benefits of this medicine. You should discuss this with your doctor.
  • The risk of blood clots forming in the veins (venous thromboembolism) while taking this medicine may be temporarily increased if you are immobile for prolonged periods of time, for example if you have a major accident or major surgery. For this reason, your doctor will usually recommend that you stop taking this pill for a period of time (usually six weeks) prior to any planned surgery, particularly abdominal surgery or orthopaedic surgery on the lower limbs (but not before minor surgery like teeth extraction). You will also need to stop taking this pill if you are going to be immobile for long periods, for example because you are confined to bed or have a leg in a plaster cast. You should not start taking the pill again until at least two weeks after you are fully mobile. There may also be an increased risk of blood clots in the veins if you are travelling for long periods of time where you will be sat still (over five hours). The risk of blood clots during long journeys may be reduced by appropriate exercise during the journey and possibly by wearing elastic hosiery. Discuss this with your doctor.
  • It is important to be aware that women using hormonal contraceptives appear to have a small increase in the risk of being diagnosed with breast cancer, compared with women who do not use these contraceptives. Women who use oral contraceptives for longer than five years may also have a small increase in the risk of being diagnosed with cervical cancer. However, these risks must be weighed against the benefits of using the contraceptive, which include a decrease in the risk of cancers of the ovaries and endometrium (womb). You should discuss the risks and benefits of the pill with your doctor before you start taking it.
  • Stop taking this medicine and inform your doctor immediately if you get any of the following symptoms while taking the medicine: stabbing pains and/or unusual swelling in one leg, pain on breathing or coughing, coughing up blood, sudden breathlessness, sudden severe chest pain, migraine or severe headaches, sudden disturbance in vision, hearing or speech, sudden weakness or numbness on one side of the body, fainting, collapse, epileptic seizure, significant rise in blood pressure, itching of the whole body, yellowing of the skin or whites of the eyes (jaundice), severe stomach pain, severe depression, or if you think you could be pregnant.

Not to be used in

  • Men.
  • Known or suspected pregnancy.
  • Breastfeeding.
  • Women with a personal or family history of a blood clot in a vein (venous thromboembolism), eg in the leg (deep vein thrombosis) or in the lungs (pulmonary embolism).
  • Blood disorders that increase the risk of blood clots in the veins, eg antiphospholipid syndrome or factor V Leiden.
  • Long-term condition called systemic lupus erythematosus (SLE).
  • Excess of urea in the blood causing damaged red blood cells (haemolytic uraemic syndrome).
  • Anaemia caused by a hereditary blood disorder where abnormal haemoglobin is produced (sickle cell anaemia).
  • Women with two or more other risk factors for getting a blood clot in a vein, eg obesity, varicose veins, long-term immobility.
  • Women who have ever had a blood clot in an artery, eg a stroke or mini-stroke caused by a blood clot, or a heart attack.
  • Angina.
  • Heart valve disease.
  • Irregular heartbeat caused by very rapid contraction of the top two chambers of the heart (atrial fibrillation).
  • Moderate to severe high blood pressure (hypertension).
  • High cholesterol levels.
  • Severe diabetes with complications, eg affecting the eyes, kidneys or nerves.
  • Women who smoke more than 40 cigarettes per day.
  • Women over 50 years of age.
  • 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, age over 35 years, 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.
  • History of breast cancer.
  • Cancer involving the genital tract.
  • Vaginal bleeding of unknown cause.
  • Severe liver disease, eg liver cancer, hepatitis.
  • History of liver disease when liver function has not returned to normal.
  • Disorders of bile excretion that cause jaundice (eg Dubin-Johnson or Rotor syndrome).
  • Gallstones (cholelithiasis).
  • 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.

Use with caution in

  • Women aged over 35 years.
  • Women whose parent, brother or sister had a stroke caused by a blood clot or a heart attack before the age of 45.
  • Obesity.
  • Smokers.
  • Diabetes mellitus.
  • High blood pressure (hypertension).
  • Women who use a wheelchair.
  • Varicose veins.
  • History of inflammation of a vein caused by a superficial blood clot (thrombophlebitis).
  • History of severe depression.
  • History of migraines.
  • Inflammatory bowel disease, eg Crohn's disease or ulcerative colitis.
  • History of liver disease.
  • History of gallstones.
  • Decreased kidney function.
  • Heart failure.
  • Personal or family history of raised levels of fats called triglycerides in the blood (hypertriglyceridaemia).
  • Close family history of breast cancer (eg mother or sister has had the disease), or women with gene mutations that are associated with breast cancer, eg BRCA1.
  • 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 medicine.

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 must not be used during pregnancy. This is because androgens are needed for the development of the sexual organs in a male foetus, and the anti-androgen action of this medicine could therefore prevent the normal development of a male foetus. The risk of this (known as feminisation) in humans is unknown, but because of the potential risk you must not take this medicine if you are pregnant. If you do not have a withdrawal bleed in your pill-free week you must make sure you are not pregnant before you start your new pack. Discuss this with your doctor.
  • This medicine should not be used by breastfeeding mothers because the cyproterone may be harmful to a nursing infant. Discuss this with your doctor.

Side effects

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 does not mean that all people using this medicine will experience that or any side effect.

  • Change in menstrual bleeding.
  • Menstrual spotting or breakthrough bleeding.
  • Headache.
  • Upset stomach.
  • Nausea and vomiting.
  • Breast tenderness.
  • Weight changes.
  • Decreased sex drive.
  • Depressed mood.
  • Retention of water in the body tissues (fluid retention).
  • Vaginal thrush (candidiasis).
  • Irregular brown patches on the skin, usually of the face (chloasma).
  • Steepening of corneal curvature which may make contact lenses uncomfortable.
  • Rise in blood pressure.
  • Disturbance in liver function.
  • Gallstones.
  • 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.

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 start taking this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while using this one, to ensure that the combination is safe.

You should not take any other hormonal contraception while taking this medicine, as this will expose you to excessive doses of hormones and is not necessary for effective contraception. (However, also see below.)

The following medicines speed up the breakdown of the hormones in this medicine by the liver, which makes it less effective as an acne and hirsutism treatment and at preventing pregnancy:

  • aprepitant
  • bosentan
  • barbiturates
  • carbamazepine
  • eslicarbazepine
  • modafinil
  • nevirapine
  • oxcarbazepine
  • phenobarbital
  • phenytoin
  • primidone
  • rifampicin
  • rifabutin
  • ritonavir
  • the herbal remedy St John's wort (Hypericum perforatum)
  • topiramate.

If you regularly take any of these medicines, Dianette is not recommended for you, because these medicines are likely to make it ineffective.

If you are prescribed a short course (up to two months) of any of the above medicines they will also make Dianette less effective. Your doctor may recommend that you temporarily stop using this medicine and use a different form of contraception to prevent pregnancy. However, if you want to keep taking this pill, your doctor may advise you to take three packets back to back without a break, then have only a four day pill-free break, then take three packets back to back again. (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, or ask you to take two pills per day. (This is also unlicensed.) 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 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 Dianette and get diarrhoea that lasts for more than 24 hours, you should follow the instructions for missed pills described above.

The pill may antagonise 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 antagonise 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 antagonise 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:

  • melatonin
  • selegiline (should be avoided in combination with the pill)
  • tacrolimus
  • theophylline (reduced dose of theophylline may be needed)
  • tizanidine
  • voriconazole.

Other medicines containing the same active ingredients

Acnocin Cicafem Clairette

Co-cyprindiol tablets are also available without a brand name, ie as the generic medicine.