How does Agomelatine work?

Depression is thought to be linked to low levels of naturally-occurring chemical messengers in the brain. These messengers are called neuro-transmitters. They send electrical impulses between different parts of the brain. In depression, three neuro-transmitters are known to be important. These are called dopamine, (pronounced dope-a-mean) noradrenaline (pronounced nor-ad-ren-a-linn), and serotonin (pronounced seer-o-tone-in). Serotonin is also sometimes called 5HT for short.

Most antidepressants work by increasing the levels of either noradrenaline or serotonin in the brain; some work by increasing the levels of both of them. It doesn’t seem to matter which neuro-transmitter is increased, all antidepressants are about equally effective.

Antidepressants that increase the level only of serotonin are called selective serotonin re-uptake inhibitors or SSRI for short. SSRI antidepressants are the ones that are most widely used in Britain.

Agomelatine is a new type of antidepressant

The way it works is different from other antidepressants. It has two actions.

The first is to improve sleep. Agomelatine mimics the activity of a substance called melatonin. This is the brain chemical that we all have which helps us to get to sleep. By mimicking the action of melatonin, Agomelatine helps people with depression to sleep. This is important, because people with depression often have problems sleeping.

The second action is to increase the levels of dopamine and noradrenaline in a part of the brain called the frontal cortex. This is the part of the brain that controls our moods, and increasing the activity of dopamine and noradrenaline here helps to lift the symptoms of depression.

How should treatment with Agomelatine be started, and what is the usual dose?

Agomelatine should be started at the recommended dose of 25mg (one tablet) a day, which MUST BE TAKEN AT BED-TIME.

After two weeks, if there has been no improvement, increasing the dose to 50mg (two tablets) at bed-time should be considered.

Is there anything else I should know about Agomelatine?

No. But here’s a summary of the key points about Agomelatine.

How should treatment with Agomelatine be stopped?

With some antidepressants, if you stop taking them suddenly, side effects – called discontinuation symptoms – can happen.

Agomelatine does not cause this problem. When you and your doctor agree that it’s time for your treatment to finish, you can just stop taking the tablets.

Some antidepressants – especially Paroxetine and Venlafaxine – are more likely to cause discontinuation symptoms than others.

This is NOT a sign that you are getting hooked on them – antidepressants do not cause drug dependence.