Co-Cyprindiol

Co-cyprindiol (also written as cocyprindiol) is a combined hormonal preparation containing two active ingredients - cyproterone acetate and ethinylestradiol - used in the treatment of androgen-dependent conditions in women, primarily severe acne that has not responded to prolonged antibiotic therapy, and hirsutism (excessive facial or body hair growth). It is also commonly known by the brand name Dianette and provides contraceptive cover as a secondary benefit.

How Co-cyprindiol Works

Co-cyprindiol combines an antiandrogen (cyproterone acetate) with a synthetic oestrogen (ethinylestradiol) in a formulation similar in structure to a combined oral contraceptive pill (COC). Cyproterone acetate competitively blocks androgen receptors, particularly in the sebaceous glands and hair follicles, reducing the stimulatory effect of androgens such as testosterone and dihydrotestosterone (DHT) on these tissues. This leads to a reduction in sebum production, improvement in acne, and a gradual reduction in unwanted hair growth. Ethinylestradiol suppresses LH and FSH secretion from the pituitary, reducing ovarian androgen production and providing the hormonal balance that enables reliable contraception.

Use for Acne and Hirsutism

Co-cyprindiol is specifically indicated for severe acne, predominantly of the facial type, when associated with seborrhoea, and for mild hirsutism. It is not a first-line acne treatment and should be reserved for cases that have not responded to adequate courses of topical and oral antibiotics. Clinical improvement in acne is typically seen after 3 to 4 months, and most patients see maximum benefit after 9 to 12 months. Unlike standard COCs, co-cyprindiol should be discontinued 3 to 4 cycles after the acne or hirsutism has fully resolved. It should not be used indefinitely purely as a contraceptive, as safer alternatives with lower VTE risk are available.

VTE Risk

A critically important safety consideration is that co-cyprindiol is associated with a higher risk of venous thromboembolism (VTE) - including deep vein thrombosis (DVT) and pulmonary embolism (PE) - compared with lower-risk combined oral contraceptives such as those containing levonorgestrel or norethisterone. Prescribers must carefully assess each patient's VTE risk factors before initiating treatment, and patients should be counselled about the signs of DVT and PE.

How to Take Co-cyprindiol

Co-cyprindiol is taken once daily for 21 consecutive days, followed by a seven-day break. A withdrawal bleed usually occurs during the break. Start the next pack on day 8, even if the withdrawal bleed has not yet finished.

Ideally start on the first day of your period for immediate contraceptive protection. If you start on days 2 to 5, use condoms for the first seven days. Take each tablet at the same time each day, swallowed whole with water. If you miss a tablet by more than 12 hours, use condoms for the next seven days and follow the instructions in the patient leaflet.

Duration of Treatment

Co-cyprindiol is intended as a treatment for acne and unwanted facial hair, not as a long-term contraceptive indefinitely. Once your acne has been well controlled for three to four months, your doctor will usually suggest switching to a standard contraceptive pill or another contraceptive method.

Co-cyprindiol contains a fixed combination of cyproterone acetate 2 mg and ethinylestradiol 35 mcg per tablet.

Standard dosing regimen: One tablet taken orally once daily for 21 days, followed by a 7-day tablet-free interval.

Duration of treatment: Treatment should continue for at least 3 to 4 cycles before assessing the response in acne or hirsutism. Maximum benefit is typically seen after 9 to 12 months. Once the condition has fully resolved, treatment should be continued for an additional 3 to 4 cycles and then discontinued.

Co-cyprindiol is not intended for long-term use as a contraceptive method - once the acne or hirsutism has resolved, the prescriber should consider switching to an appropriate standard combined oral contraceptive if ongoing contraception is required.

Co-cyprindiol is not appropriate for postmenopausal women, in men (cyproterone acetate is available separately for use in men for prostate cancer management), or in women under 18 years without specialist supervision. Standard combined pill dosing rules regarding drug interactions, missed pills, and vomiting/diarrhoea apply.

Common Side Effects

• Nausea, particularly in the first few cycles
• Breast tenderness or enlargement
• Headache or migraine
• Mood changes, including low mood or emotional sensitivity
• Reduced sex drive
• Breakthrough spotting or irregular bleeding in the first cycles
• Skin changes (initially acne may temporarily worsen before improving)

Serious Risks

Co-cyprindiol carries a higher risk of blood clots (venous thromboembolism) than most other combined pills, because cyproterone acetate increases the thrombotic risk beyond that of oestrogen alone. Do not take co-cyprindiol if you have a personal or family history of blood clots, or if you smoke and are over 35. Seek immediate medical attention if you develop sudden leg pain or swelling, chest pain, or difficulty breathing.

Venous Thromboembolism Risk

Co-cyprindiol carries a higher risk of venous thromboembolism than standard combined oral contraceptives containing levonorgestrel or norethisterone. Before prescribing, clinicians must assess each patient's VTE risk, including factors such as personal or family history of DVT or PE, obesity, prolonged immobility (such as long-haul flights or post-surgical recovery), and smoking. Women with significant VTE risk factors should not use co-cyprindiol unless there is no suitable alternative for their androgen-dependent condition. All women starting co-cyprindiol should be counselled about the symptoms of DVT and PE and advised to seek emergency care immediately if they experience sudden swelling, pain, or redness in a leg, sudden chest pain, or breathlessness.

Not for Contraception Alone

Co-cyprindiol must not be used solely as a contraceptive without an underlying indication of androgen-dependent acne or hirsutism, because its VTE risk exceeds that of standard combined pills. Once the dermatological indication has resolved and treatment is discontinued, women who require contraception should be switched to an appropriate alternative. Concurrent use of hepatotoxic medicines, particularly other drugs associated with liver damage, should be avoided. Co-cyprindiol does not protect against sexually transmitted infections.

Co-cyprindiol is contraindicated in the following circumstances:

• Current or past venous thromboembolism (DVT or PE) or known predisposition (e.g., activated protein C resistance, factor V Leiden mutation)
• Current or past arterial thrombotic disease including stroke, TIA, myocardial infarction, or angina
• Migraine with aura
• Severe or multiple cardiovascular risk factors
• Diabetes mellitus with vascular complications
• Severe liver disease, hepatic tumours, or cholestatic jaundice
• Undiagnosed vaginal bleeding
• Known or suspected oestrogen-dependent neoplasms (e.g., breast cancer)
• Pregnancy or breastfeeding
• Hypersensitivity to cyproterone acetate, ethinylestradiol, or any excipient
• Uncontrolled hypertension