Valdoxan (Agomelatine)

How does it work?

Valdoxan tablets contain the active ingredient agomelatine, which is a type of medicine called an antidepressant. It is used to treat depression.

Agomelatine acts on the melatonin and serotonin receptors in the brain.

Melatonin is a hormone made by the pineal gland, a structure in the brain. It is normally released soon after it starts to get dark. The amount produced then increases until about four am, before dropping off again. Melatonin is linked with the control of circadian rhythms and promoting sleep. It works by acting on melatonin receptors in the brain.

Agomelatine mimics the action of melatonin and helps to re-synchronise the body’s circadian rhythms. These include mood, anxiety, appetite, body temperature and sleep/wake cycles. These circadian rhythms, particularly sleep cycles, are severely disturbed in people with depression. Agomelatine’s main action is to improve the onset and quality of sleep and this in turn has an antidepressant effect.

Agomelatine also helps to improve mood in depression by increasing noradrenaline and dopamine release in the brain. These are natural chemicals called neurotransmitters that are involved, amongst other things, in regulating mood.

What is it used for?

  • Major episodes of depression in adults.

How do I take it?

  • The usual dose of Valdoxan is one tablet daily, taken at bedtime. If your symptoms have not started to improve after two weeks of taking one tablet daily, your doctor may increase your dose to two tablets daily, taken together at bedtime. Follow the instructions given by your doctor.
  • Valdoxan tablets can be taken either with or without food.
  • If you forget to take a dose don't worry, just take your next dose as normal the following bedtime. Do not take a double dose to make up for a missed dose.
  • Treatment with antidepressants is normally continued for at least six months. When your doctor decides it is time for you to stop treatment Valdoxan can be stopped without needing to reduce the dose down gradually first.


  • This medicine may cause sleepiness or dizziness and so could reduce your ability to drive or operate machinery safely. Do not drive or operate machinery until you know how this medicine affects you and you are sure it won't affect your performance.
  • It is recommended that you avoid drinking alcohol while taking this medicine.
  • Depression and other psychiatric illnesses are associated with an increased risk of suicidal thoughts, self-harm, and suicide. You should be aware that this medicine may not start to make you feel better for at least two to four weeks. However, it is important that you keep taking it in order for it to work properly and for you to feel better. If you feel your depression or anxiety has got worse, or if you have any distressing thoughts, or feelings about suicide or harming yourself in these first few weeks, or indeed at any point during treatment or after stopping treatment, then it is very important to talk to your doctor. You may be more likely to have thoughts about harming or killing yourself before this medicine starts to work if you have previously had thoughts like this, or if you are under 25 years of age. It can be helpful to tell a close friend or family member that you are depressed and having treatment, and ask them to tell you if they think your depression has got worse or they are worried about your behaviour.
  • This medicine can cause liver problems on rare occasions. For this reason, you will need to have a blood test to check your liver function before you start treatment with this medicine. This should be repeated 3, 6, 12 and 24 weeks after starting treatment, and then as your doctor feels necessary. If your dose is increased at any point your liver function should be checked 3, 6, 12 and 24 weeks after the increase. You should stop taking this medicine and consult your doctor straight away if you develop any of the following symptoms while taking this medicine, as they could be signs of a problem with your liver: unexplained itching, yellowing of the skin or eyes, unusually dark urine or pale stools, unexplained nausea and vomiting, pain in the upper right abdomen or sudden new unexplained fatigue.

Use with caution in

  • People over 65 years old.
  • People with decreased kidney function.
  • Young adults (aged under 25 years).
  • People with a history of suicidal thoughts or attempted suicide.
  • People with a history of bipolar disorder (manic depression), mania or hypomania.
  • People who are obese or overweight.
  • People who are alcoholic or drink large quantities of alcohol.
  • People with raised liver enzymes before starting treatment.
  • People taking other medicines that can affect the liver.

Not to be used in

  • People with decreased liver function, active liver disease or liver cirrhosis.
  • Elderly people with dementia.
  • People taking fluvoxamine (an antidepressant) or ciprofloxacin (an antibiotic).
  • Rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption (Valdoxan tablets contain lactose).
  • This medicine is not recommended for children or adolescents under 18 years old, as its safety and effectiveness have not been established in this age group

This medicine should not be used if you are allergic to 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.

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.

  • The safety of this medicine for use during pregnancy has not been investigated. If you do get pregnant while using this medicine you should consult your doctor straight away. This medicine should be used with caution during pregnancy and only if the benefits to the mother outweigh any potential risks to the developing baby. Seek medical advice from your doctor.
  • It is not known if this medicine passes into breast milk. The manufacturer recommends that women who need to take this medicine should not breastfeed. Seek further medical advice from 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.

Common (affect between 1 in 10 and 1 in 100 people)

  • Headache.
  • Migraine.
  • Dizziness.
  • Drowsiness.
  • Fatigue.
  • Difficulty sleeping (insomnia).
  • Anxiety.
  • Disturbances of the gut, such as nausea, diarrhoea, constipation, abdominal pain.
  • Excessive sweating.
  • Back pain.
  • Raised liver enzymes.

Uncommon (affect between 1 in 100 and 1 in 1000 people)

  • Blurred vision.
  • Pins and needles sensations (paraesthesia).
  • Feeling agitated, irritable or restless.
  • Aggression.
  • Abnormal dreams or nightmares.
  • Eczema.
  • Itching.

Rare (affect between 1 in 1000 and 1 in 10,000 people)

  • Red rash.
  • Liver problems such as inflammation of the liver (hepatitis) - see warning section above.
  • Hallucinations.

Unknown frequency

  • Suicidal thoughts or behaviour (see warning section 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 treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to ensure that the combination is safe.

Agomelatine should not be taken in combination with the antidepressant fluvoxamine or the antibiotic ciprofloxacin. Fluvoxamine and ciprofloxacin both increase the amount of agomelatine in the body, by preventing its breakdown.

Other medicines containing the same active ingredient

There are currently no other medicines available in the UK that contain agomelatine as the active ingredient.