Side effects
Some of the side effects you may get when you start taking agomelatine should get better or disappear after a few days. If they do not, or they get worse, you should go back to your doctor.
If you get any side effects not listed here please look at the patient leaflet in the medicine pack, or speak to your pharmacist or doctor.
Very common side effects, which affect more than one in ten people, include:
Common side effects, which affect up to one in ten people, include:
- anxiety
- nausea and vomiting
- stomach pain
- abnormal dreams
- insomnia
- dizziness
- drowsiness and fatigue
- increase in weight
- change in bowel habits
- back pain
- changes in liver enzymes (this is why it is important to ensure you have regular blood tests)
There are other side effects you can get when taking this medicine. We have only included the most common ones here.
Please do not worry about these side effects. Some people will not get any side effects at all.
If you think you are getting side effects from taking agomelatine, speak to your doctor or pharmacist.
If you do get a side effect, please think about reporting it via the 'Yellow Card' system.
Body
Some people find that, in the long term, they gain a little weight while taking agomelatine. This may be due in part to their appetite returning.
Some people may find that their weight goes down while taking agomelatine, although this is rarer.
It is very difficult to know how agomelatine will affect each person who takes it. If you start to notice a change in your weight while taking agomelatine, talk to your doctor or pharmacist.
Sleep
Agomelatine may make you feel drowsy for a few days after you start taking it. This should pass after the first week or two.
If you feel like a zombie, and you've been taking it for more than a month, you should speak to your doctor.
Sex and fertility
Sex
Agomelatine is unlikely to cause side effects that will directly affect your sex life.
Fertility
There is no evidence to suggest that taking agomelatine will affect your fertility.
Agomelatine will not affect how contraceptive pills or the 'morning after' pill work. Contraceptive pills containing oestrogen are likely to increase the level of agomelatine in your body, but studies have shown that there is no need to reduce your dose of agomelatine.
Taking agomelatine should not affect your periods.
Pregnancy and breastfeeding
Pregnancy
There is no evidence to suggest that taking agomelatine while you are pregnant is harmful, but there is not much information available.
Talk to your doctor if you are trying to get pregnant while taking agomelatine.
If you do become pregnant while you are on agomelatine, you should carry on taking your medicine and speak to your doctor about this as soon as possible. They can help you decide whether or not to continue taking agomelatine.
If you do stop taking agomelatine and become unwell, this may be more harmful to your baby than staying on the medicine.
If you and your doctor agree that it is best for you to continue taking agomelatine while pregnant, you should tell your midwife.
Breastfeeding
There is no specific information about whether agomelatine is passed on to the baby through breastmilk, but since this is the case with most other drugs, it is likely that it is also the case with agomelatine.
If your baby was born early, then breastfeeding is not recommended as your baby may not safely be able to get rid of the agomelatine.
If your baby becomes restless, very sleepy or develops feeding problems, stop breastfeeding and seek medical advice urgently.
Please talk to your midwife, doctor or pharmacist if you want to breastfeed while taking agomelatine.
Driving and transport
Do not drive a car or ride a bike just after you start taking agomelatine.
Taking agomelatine may affect your ability to do things like drive a car, ride a bike, or anything else that needs a lot of focus. It might be best to stop doing these things for the first few days, until you know how it affects you.
Do not worry - most people do these things as normal while taking agomelatine.
School and exams
Try not to take agomelatine for the first time just before your exams, as it may affect your concentration.
You should talk to your doctor about any future exams if you are starting agomelatine.
You might decide together to delay starting it until you have done them.
If they are more than a month away, however, you might find that it is better to start agomelatine to improve your motivation to study.
Bear in mind that depression itself can also affect concentration.
Do not worry though - most people take exams as normal while on agomelatine.
Friends and family
You may want to let your family and friends know you are taking agomelatine so they can support you and help you look out for side effects.
For guidance on this, check out our page on getting support with your medication.
Sport
Agomelatine is not a banned substance in sport.
It may affect your ability to play sports that require a lot of focus, so it is a good idea to stop doing these sports for a short while until you know how it affects you.
Do not worry - most people play sports as normal while taking agomelatine.
Alcohol, street drugs and smoking
Alcohol
You can continue to drink alcohol in small amounts while taking agomelatine. You are likely to find that alcohol makes you feel more sleepy, so it might be best to stop drinking alcohol for a short while until you see how agomelatine affects you.
Street drugs
We do not know exactly how agomelatine interacts with street drugs and legal highs.
However, using cannabis while on agomelatine can make drowsiness worse and slow your reaction time.
Cannabis and other drugs may have their own side effects on your mental health, like anxiety or psychosis. For more information, have a look at our drugs and alcohol page.
Using heroin or methadone while on agomelatine can make drowsiness worse.
Smoking
Smoking affects the level of agomelatine in your body. If you smoke, then your body breaks agomelatine down more quickly. This means you may need a higher dose for the medicine to be effective.
If you stop smoking while taking this medicine, then your agomelatine levels will go up, meaning you may need to lower your dose so you don't get side effects.
Moving to nicotine replacement therapies or vaping will have the same effect on agomelatine levels as stopping smoking. This is because it is the chemicals in the smoke that cause your liver to break down the agomelatine more quickly.
If you smoke, or are thinking about stopping, then please speak to your doctor about this. They can give you advice and help with stopping smoking.
Prescription medicines
Agomelatine can interact with some other medicine and drugs. Always talk to your doctor if you are taking other medicines.
Do not take agomelatine if you are taking the herbal remedy St. John's Wort. St. John's Wort is a herbal medicine available over the counter in shops that can also be used for low mood. It does not mix well with any antidepressant, so please tell your doctor or pharmacist if you are trying this or want to try it.
Tell the pharmacist you are taking agomelatine when you buy medicines from a pharmacy, including things you put on your skin.
References and further reading
For more helpful links and information, have a look at our references and further reading page.