Melatonin

What melatonin is for

Melatonin is a medicine used to treat sleep problems, such as difficulty getting to sleep or staying asleep (insomnia).

It's also used to treat sleep problems in people with learning disabilities and children who have ADHD.

It can be prescribed if other methods have not worked.

It's sometimes used to help with symptoms of jet lag, which include tiredness and difficulty sleeping after travelling across different time zones.

Melatonin is a hormone made by your body which regulates your sleep and wake cycle.

How to take melatonin

Melatonin usually comes as tablets, capsules or liquid (oral solution) that you swallow.

How much you take and how long for will depend on why you're taking it and your symptoms.

When taking melatonin tablets or capsules:

• take them before bedtime – follow your doctor's advice and check the leaflet that comes with your medicine for instructions on how soon before bedtime you should take them
• swallow the tablet or capsule whole with a drink of water, milk or fruit juice

When taking melatonin oral solution:

• take it 30 minutes to 1 hour before bedtime
• use the spoon that comes with the medicine to help you measure the right dose
• you can swallow the solution with a drink of water, milk or fruit juice

Check the leaflet that came with your medicine for advice on whether you can take it with food.

Always check the packet or leaflet that comes with your medicine. Ask a pharmacist or doctor for advice if you're not sure how to take it or have any problems taking it.

If you miss a dose of melatonin

If you forget to take a dose of melatonin at bedtime, skip the missed dose and take your next dose at the usual time.

Do not take 2 doses to make up for a forgotten dose.

If you take too much melatonin

Taking an extra dose of melatonin may make you feel sleepy. It's unlikely to cause problems, but it's important to get medical advice if you take too much.

Side effects of melatonin

Like all medicines, melatonin can cause side effects, although not everyone gets them.

Side effects of melatonin include:

• feeling sleepy during the daytime
• headaches
• stiff or painful joints
• being sick (vomiting) or feeling sick (nausea)

Do not drive, ride a bike or use machinery after you take melatonin because it can make you sleepy. If you feel sleepy, wait until you no longer have these symptoms.

Serious side effects

Melatonin can sometimes cause serious side effects, although most of them are rare.

Possible serious side effects of melatonin include:

• an allergic reaction (anaphylaxis) – which can cause symptoms such as a swollen throat or tongue, a raised, itchy rash or difficulty breathing
• chest pain or heart palpitations
• seizures (fits)
• fainting
• bleeding that does not stop, unexplained bleeding or blood in your pee
• mood changes

Who can and cannot take melatonin

Most adults can take melatonin. It's sometimes also prescribed for children.

But melatonin is not suitable for everyone. For example, it may not be suitable if:

• you've had an allergic reaction or other serious side effect from melatonin
• you have epilepsy
• you have liver or kidney problems
• you have an autoimmune condition, such as lupus or psoriasis

Before taking melatonin, tell your doctor if you have any medical conditions, or if you smoke.

Breastfeeding and melatonin

Tell your doctor if you're breastfeeding. They may prescribe a different medicine to help with your sleep problems.

Melatonin is not usually used while breastfeeding because there's a risk it could cause your baby to have side effects.

Do not sleep in the same bed (co-sleep) with your baby if you've taken melatonin or any other medicine that makes you sleepy or drowsy, as it can increase the risk of sudden infant death syndrome (SIDS).

Pregnancy and melatonin

Melatonin is not usually used during pregnancy. Tell your doctor if you're pregnant or trying to get pregnant.

They may give you advice to help you sleep or prescribe a different medicine.

Taking melatonin with other medicines, food and drink

There are some medicines, remedies and supplements that may not mix well with melatonin.

This includes:

• non-steroidal anti-inflammatory medicines (NSAIDS), such as ibuprofen
• medicines that can cause drowsiness, such as zopiclone
• warfarin, used to prevent blood clots
• some types of antidepressants, such as fluvoxamine
• medicines used to treat seizures, such as carbamazepine
• the combined contraceptive pill
• hormone replacement therapy (HRT)

Before taking melatonin, tell your doctor if you're taking any other medicines, herbal remedies, vitamins or supplements.

Food, drink and alcohol with melatonin

You can eat and drink as normal while taking melatonin, but check the leaflet that came with your medicine for advice on whether you can take it with food.

Try to avoid alcohol while taking melatonin because it can stop your medicine working properly, and increase your chance of having side effects.