Clomifene

What it is used for

• Infertility caused by not ovulating regularly, including in polycystic ovary syndrome (PCOS)

Read our guides:

• Polycystic ovary syndrome (PCOS)

Off-label uses

Doctors sometimes prescribe a medicine for a condition it is not officially licensed for. This is called off-label use. It is legal and common when there is good evidence it helps, and your doctor should explain why they are suggesting it.

• Some types of male infertility caused by low hormone levels, under a specialist

How it works

Clomifene blocks oestrogen receptors in the brain. The brain responds by releasing more of the hormones that stimulate the ovaries to develop and release an egg.

Side effects

Like all medicines, Clomifene can cause side effects, although not everyone gets them. Many are mild and ease after the first few weeks.

Common side effects

• hot flushes
• tummy discomfort or bloating
• feeling sick
• headache
• breast tenderness
• mood swings

Tell your doctor or pharmacist if these bother you or do not go away.

Serious side effects

These are rare. Call 111 or contact your doctor straight away if you get:

• blurred vision, spots or flashes in your vision. Stop and contact your doctor
• severe tummy pain or swelling, breathlessness or peeing less, which can be signs of ovarian hyperstimulation syndrome

Call 999 if you have signs of a serious allergic reaction, such as swelling of your lips, mouth, throat or tongue, or trouble breathing.

You can report any side effect to the Yellow Card scheme, run by the medicines regulator.

Stopping and withdrawal

Important safety information

• It increases the chance of twins.
• You should have scans to check how your ovaries are responding, at least in the first cycle.
• It is usually started by a fertility specialist.

Questions about your medicine?

A pharmacist can answer questions about your medicines for free, without an appointment. You can also ask your GP for a medication review. Check if you can get free prescriptions.