Duloxetine

Medication name

Duloxetine ("Dew-LOX-et-een")
Brand names

Cymbalta ("Sim-BAL-ta")

Yentreve ("Yen-tree-ve")
Medication type

Serotonin-noradrenaline reuptake inhibitor (SNRI)

Capsules: 20mg*, 30mg, 40mg* or 60mg strengths

The Yentreve brand, available as 20mg and 40mg capsules, is specifically for stress incontinence rather than depression and anxiety disorders, although the medication is the same.

If you are 18 or over, duloxetine can be prescribed for you as a licensed medicine for depression (low mood), generalised anxiety disorder and some other conditions.

If you are under 18, a specialist doctor may still consider this as a treatment option.

Read our guide to depression

About duloxetine

Duloxetine is a type of antidepressant called a serotonin and noradrenaline reuptake inhibitor (SNRI).

Serotonin (also called '5HT') and noradrenaline are a naturally occurring chemical messengers (or ‘neurotransmitters’) that have an important role in areas of the brain that control mood thinking, feelings and emotions. Research suggests that depression is more likely to occur when the brain doesn’t have enough of these chemical messengers.

SNRIs like duloxetine are thought to work by increasing levels of serotonin and noradrenaline in the brain.

They can also cause an increase in dopamine (another naturally occurring chemical messenger) in some areas of the brain.
Depression, and other conditions like anxiety disorders, are not just caused by low serotonin and noradrenaline levels, but a rise in these chemicals can improve symptoms and help you to feel better.

Duloxetine and everyday life

Duloxetine should start helping with depression within one to two weeks. It may take four weeks or longer for you to get the full effect.

How people respond to treatment can vary. Sometimes improvement is slow, and you may not feel any different to start with. This can be hard when your mood is low, and if you experience any side effects from your medication you may think you feel worse and not better. If you can, give your medication a chance to work and continue to take it for at least three to four weeks to see if it makes a difference.

Your parents, friends and doctor may notice an improvement in you before you feel it yourself, so it’s a good idea to talk to them.

If you think your medicine has not made any difference to how you feel after three to four weeks, you should go back to your doctor. They might recommend a change in dose or a different medication. However, it can take longer to work for some people than for others, so they may suggest you wait six to eight weeks before deciding.

For anxiety, it may take longer for the benefits to be noticed. It could take up to three months before you feel the full benefit.

For some people, anxiety symptoms briefly increase at the start of treatment, but the anxiety should decrease over time as you continue to take your medicine. To avoid or minimise this, your doctor will usually start treatment with a low dose and increase this after one to two weeks.

Duloxetine can make you less hungry than normal, which might lead to weight loss.

In studies, some children and young people under 18 who took duloxetine had some weight loss at first, but after six months of treatment they went back to normal compared with other people of the same age.

It is not possible to predict how duloxetine will affect each person before they start taking it. Talk to your doctor or pharmacist if you are concerned about your weight, or changes to your weight, while taking duloxetine.

A common side effect of duloxetine is a dry mouth. Over a long time, this can increase your risk of developing tooth decay or gum disease. Make sure you brush your teeth well and have regular dental check-ups. Speak to your dentist, doctor or pharmacist about things you can do to help.

You may want to let your family and friends know you are taking duloxetine 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.

You can feel sleepy in the first few days of taking duloxetine. But this should get better after the first week or two. If it makes you tired, try taking it just before you go to bed.

It can also give you sleep problems, including unusual dreams. If you find it hard to get to sleep, try taking it in the morning.

If you experience any of these side effects and have been taking duloxetine for more than a month, you should go back to the doctor and discuss what changes could be made to help. This may include switching to a different medication.

Alcohol

It may be possible to drink some alcohol in moderation while taking duloxetine.

However, the two together might make you feel very sleepy and unsteady on your feet, especially when you first start taking the medication.

During the first few weeks of treatment, it is recommended that you don’t drink alcohol until you know how the medicine affects you.

Drinking alcohol every day, or in large amounts, can make your symptoms worse and may mean you won’t get the maximum benefit from your medication.

Street drugs

Cannabis can make drowsiness, dizziness and confusion worse when taken with duloxetine.

Cannabis and other drugs may have their own side effects on your mental health, like anxiety or psychosis.

Methadone can make sleepiness worse with duloxetine. The duloxetine could increase the concentration of methadone in your body. In some circumstances, you may be prescribed methadone by your doctor. If so, your doctor will monitor your medicines carefully and will adjust the dose if needed.

Duloxetine is likely to raise the effect of cocaine in your body, giving you a bigger reaction.

Taking duloxetine with cocaine or ecstasy or amfetamines could bring on serotonin syndrome. You could get a high temperature/fever, agitation, confusion, trembling or weird muscle movements. You need to go to hospital if this happens. Tell the doctor everything that you have taken.

There are many other street drugs, but we don’t know what effect taking them with duloxetine will have, so it’s best to be cautious. There is no regulation of street drugs or ‘legal highs’, so even if there are no known issues with the medication you take, the supply you receive might be mixed with other substances that could be dangerous.

Smoking

Cigarette smoke affects the amount of duloxetine in your body.

If you smoke, you will probably need a higher dose of duloxetine than someone who does not smoke.

Tell your doctor if you smoke, so that you get the right dose for you.

If you stop smoking or switch to vaping or a nicotine replacement product, the level of duloxetine in the body rises, and you might need to reduce your dose of duloxetine slowly. If you start or restart smoking, you will probably need to increase it again. Go to your doctor for advice if you stop or start smoking. It is the smoke, rather than nicotine, that has this effect so it should not be as much of a problem if you only vape.

Get more advice on drugs and alcohol.

Duloxetine does not mix well with some other medicines, including herbal remedies. It may affect how they work or could cause more side effects.

Do not take duloxetine if you take an antidepressant medicine called a monoamine oxidase inhibitor (MAOI), or if you have taken one in the last two weeks. MAOIs include drugs such as moclobemide, isocarboxazid, phenelzine and tranylcypromine.

Before you start taking duloxetine, tell your doctor if you are taking any other medications including things you have bought from a pharmacy or other shop for common illnesses like colds and flu or medications that you put on your skin.

Always tell the pharmacist that you are taking duloxetine if you buy any medicines from a pharmacy.

Look at the leaflet inside your medicine box for more information about other medicines that can interact with duloxetine. With some medicines your doctor may need to adjust the dose of your medicines if you take them together. Ask a doctor or pharmacist for more information if you have any questions.

The tablets may not be suitable for you if you have problems eating some sugars or dairy foods, as they contain sucrose.

Always let your pharmacist know if you have any food allergies or intolerances, and always check with them if you’re concerned about any of the ingredients in your medication.

If you need to avoid animal products such as gelatine, please note that this is often found in capsules but also in some tablet formulations. Ask your pharmacist if you have any questions about the ingredients.

Further information about practical considerations for medicines if you need to avoid animal products can be found on the Vegan Society website.

Taking duloxetine may affect your concentration, which could, in turn, affect your ability to do things like driving a car, riding a bike, using machines, or anything else that needs a lot of focus.

Duloxetine may also affect your eyesight and make you feel sleepy or dizzy.

It is recommended that you stop driving or riding a bike for the first few days or weeks, until you know how it affects you.

Most people drive as normal while taking duloxetine. If you are worried about this or have any concerns you would like to discuss, speak to your doctor or pharmacist.

Pregnancy

If you become pregnant while you are on duloxetine, you should carry on taking it and make an appointment to see your doctor as soon as possible They can discuss the benefits and risks of continuing duloxetine and help you to make a decision that is best for you and your baby. They may refer you to a specialist perinatal mental health team to support you with this decision.

You can find out more information about taking duloxetine during pregnancy Bumps (Best Use of Medicines in Pregnancy).

Untreated depression or anxiety can also be harmful to you and your developing baby, so decisions about stopping or avoiding medication when you are pregnant need to be discussed carefully with your doctor.

If you and your doctor agree that carrying on with duloxetine has more benefits than risks, you should tell your midwife that you are continuing to take this at your next appointment.

Some research has reported that taking antidepressants similar to duloxetine during the month before delivery can lead to a small increased risk of bleeding after you have given birth. It will be important for your doctor and midwife to know what medication you are taking so that appropriate monitoring and treatment is planned. If you are concerned about this, discuss it with your doctor and midwife.

If you are planning to get pregnant, it is recommended that you take folic acid while you are trying for a baby and during pregnancy. It is safe to take this together with duloxetine.

Post-natal

If duloxetine is taken in the last five months of a pregnancy, studies have shown a small increased risk of a condition called persistent pulmonary hypertension of the new-born (PPHN). PPHN can make the baby breathe faster and look a bit blue in colour.

This happens in the first 24 hours after birth. You will need help from the midwife and doctors, so it is best if they are looking out for symptoms.

The new born baby may also develop withdrawal effects such as:

irritability and crying a lot
having difficulty sleeping or sucking

These might not happen straight away, so you should look out for them over the first few days after the baby is born. These are usually mild and go away in a few days without treatment.

Breastfeeding

A small amount of duloxetine is passed to the baby in breast milk.

If your baby was born early, then breastfeeding while you are taking duloxetine may not be recommended. Talk to your midwife and doctor about feeding options.

If you breastfeed while taking duloxetine, seek urgent medical advice if your baby becomes restless, very sleepy, or develops feeding problems.

If your medication makes you sleepy, do not to sleep with your baby in the same bed, and be cautious when handling your baby (especially if waking during the night for feeds).

Sex

Duloxetine can have side effects that might affect your sex life. These include:

problems getting an erection (getting hard) and ejaculating (coming)
unusual bleeding from the vagina
testicle pain
changes in how you reach orgasm (come)
having a lower sex drive (reduced libido)

Most side effects occur when you first start medication and improve over time. If they do not, and this is a problem for you, make an appointment to discuss this with your doctor.

Some other rare side effects include breast growth or milk flow from the breasts (regardless of gender). These may affect your confidence and therefore your desire to have sex. Talk to your doctor if you get these symptoms.

In medicines that are similar to duloxetine (SSRIs) there is some evidence to indicate that side effects affecting your sex life might continue for several months or longer after you stop your medicine. This is sometimes referred to as PSSD (post SSRI sexual dysfunction). We do not know if this is the case for duloxetine. More research is needed to understand how frequently this might happen. Discuss this with your doctor or pharmacist is you are concerned.

Untreated depression or anxiety can have a negative effect on your sex life, so if duloxetine helps you to recover, positive effects can include improving your desire, experience and enjoyment of sex as your mood lifts and you become interested in life and relationships again.

Fertility

There is no clear evidence that duloxetine affects female or male fertility at doses prescribed to treat depression or anxiety.

Talk to your doctor about your duloxetine if you are trying to get pregnant.

Duloxetine is not a banned substance in sport.

Most people play sports as normal while taking duloxetine. However, taking duloxetine may affect your ability to do things like riding a bike, competitive gymnastics, or anything else that needs a lot of focus. It can affect your eyesight, make you feel dizzy and sleepy, and make you feel restless and unable to sit still.

It might be best to stop such sports for the first few days, until you know how it affects you or the effects get better.

If you are worried that taking duloxetine might make doing the sports you enjoy more difficult, discuss this with your doctor.

Ideally it is best not to take duloxetine for the first time just before your exams.

Taking duloxetine may affect your ability to do things that need a lot of focus, like revising and exams. Your eyesight may be affected, and you might have sleep problems or feel very sleepy during the day. You may also feel restless and find it hard to sit down and keep still.

You should talk to your doctor about any future exams if you are starting duloxetine. 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 duloxetine to lift your mood and improve your motivation and ability to study.

Most people take exams as normal while taking duloxetine. It you are worried that taking duloxetine might make studying for or taking your exams harder, discuss this with your doctor.

Information and safety considerations

Your doctor will consider any other medical conditions or symptoms you have before recommending a medicine for you.

Your medicine will come with a ‘patient information leaflet’. It’s important that you read this information. Speak to your pharmacist if:

you’re not given a leaflet
you don’t understand the information
you need it in a different format or language
you’re concerned about something you’ve read

The information leaflet also includes a list of warnings and precautions to consider before you take the medicine. If you think that any of these apply to you and are concerned that your doctor is not already aware of them, check with your doctor or pharmacist before you start to take your medication (or as soon as possible if you are already taking it).

Uses, warnings, safety and side effects

Taking duloxetine

Your doctor will advise you on how long it is best to keep taking your medication. This may vary depending on what you’re taking it for and how many times you’ve been unwell.

If you are prescribed duloxetine for low mood or depression, it is recommended that you take it for at least six months after you feel well again. This means that most people take it for at least seven to nine months. Research has shown that stopping it sooner, or immediately after you start to feel better, increases the risk of your low mood returning.

If you have had low mood or depression more than once, or if there is a higher risk of you becoming unwell again, your doctor may advise you to continue duloxetine for at least two years after you feel well again.

If you are prescribed duloxetine for anxiety, it is recommended that you take it for at least one year after you feel well again. Research has shown that stopping it sooner, or immediately after you start to feel better, increases the risk of your symptoms returning.

You will get the best effect from duloxetine if you take it regularly every day at the dose prescribed by your doctor.

People usually take duloxetine once a day at the same time. This could be at a mealtime, or when you brush your teeth.

If you are taking duloxetine for depression, you are likely to start taking it at the standard treatment dose. If you are taking it for anxiety, you may be started on a lower dose and increase gradually.

You can take duloxetine before or after food, but taking it with or just after food may help to minimise side effects like feeling sick.

Swallow the capsule with a drink of water – if you chew it, it tastes bitter.

If you forget to take a dose during the day, just take it as soon as possible.

If you forget to take it by the time of your next dose, only take the next dose. Do not try and catch up by taking a double dose.

If you forget to take it for a few days, you may start getting withdrawal symptoms. These should improve quickly after you start taking duloxetine again. If they do not, seek advice from your doctor or pharmacist.

If you regularly forget to take it every day, your medicine may not work as well and it could increase the risk of you becoming unwell again.

If you have been taking duloxetine regularly for more than one to two months, it is recommended that you stop gradually (ideally over at least four weeks).

Discuss stopping your medication with your doctor. If you have important events coming up or are going through a period of life which is very demanding, it might not be the best time to stop your medication. Planning and support are important to stopping your antidepressant medication successfully.

Antidepressants are not addictive, but if stopped suddenly they can cause discontinuation or withdrawal symptoms. These are caused by the receptors and levels of chemical transmitters in your brain readjusting after you reduce or stop your medication (and can also occur if you miss doses of medication).

Some of the symptoms you get may be like symptoms you had when you were unwell, so understandably, you might feel anxious or upset that your illness could be returning.

If you experience symptoms immediately or soon after stopping medication (days rather than weeks), this is usually a withdrawal symptom caused by your body adjusting to not having the medication anymore. If the symptoms start after a month or more after stopping your medicine, this might be a sign that you are becoming unwell again.

Withdrawal symptoms usually start within a few days of stopping (or sometimes reducing) your medication. A wide range of symptoms have been reported and are listed below. You may experience a few or a range of these:

dizziness and/or feeling unsteady
headaches
numbness or tingling in hands or feet
sleep disturbances (vivid dreams, nightmares, not being able to sleep)
electric shock-like feelings in the head, spine, arms, legs or hands
feeling anxious, agitated or irritable and/or restless
confused or disorientated and reduced concentration
poor appetite, feeling or being sick or having diarrhoea (loose poo)
sweating or shaking
feeling emotional, low mood and tearful
flu-like symptoms/muscle aches and pains
tinnitus (ringing in your ears)
problems with your eyes, or fluttering/pounding heartbeat (this is not as common as the other symptoms listed above)

It is not possible to predict if you will experience withdrawal symptoms, or how bad they will be if you do experience them, but studies report about half of people may get them. The risk appears to be higher if:

you have been taking your medication for six to eight weeks and you stop taking it suddenly
you are a child or young person
you experienced an increase in anxiety symptoms when you started medication
you have experienced withdrawal symptoms with another antidepressant before

If you do experience symptoms, they are usually mild and don’t last long (two to three weeks for most people), but for a few these could be severe enough to make you feel very unwell and last longer (two to three months or more). Arrange an appointment with your doctor to discuss your symptoms and seek advice if you are concerned or unable to tolerate them.

You can stop taking duloxetine safely with your doctor’s help. Planning a gradual withdrawal together can help to minimise or prevent the withdrawal symptoms you experience.

Warnings and safety

If you have taken more than the dose prescribed by your doctor, contact NHS 111 immediately to ask for advice, or ask a family member or friend to do this for you. This is important even if you don’t feel any different.

NHS 111 can give you advice and direct you to the best place to get more help if you need it.

If you have taken too much medication on purpose, or if after taking this you quickly feel unwell, call 999 or get someone to take you to A&E straight away. This includes any of the following signs:

feeling sick or being sick
having seizures or fits
an irregular heartbeat or a heart attack
extreme sleepiness that could lead to you becoming unconscious

If you need to go to A&E, do not travel alone or drive yourself there. Get your parent, family member or friend to go with you to support you and keep you safe on the way. If someone is not able to drive you there, call for an ambulance. Take your medication with you and tell doctors how much you have taken.

Suicidal thoughts

Depression (and other mental illnesses) can sometimes cause you to have thoughts about hurting yourself or taking your own life. While uncommon, this could also be a side effect of your medicine. This can happen to anyone but is more likely to happen if you are under 25 years old.

If you have any thoughts like this, it is important you get urgent help. Contact your doctor immediately for advice and support. This could be your GP or specialist mental health team. If you are able, share how you are feeling with family member or friend as well so they can support you to get help.

If you discussed with your doctor what to do if you get these thoughts and created a safety plan, read this to remind you who to contact for support and what you can do to help you cope.

Read our guide to suicidal feelings

Serious side effects

Duloxetine can cause serious side effects, including allergic reactions.
Stop taking duloxetine and go to a hospital straight away if you get any of the following symptoms:

difficulty breathing
an allergic reaction or allergy (including symptoms such as swelling of your face, eyelids, lips, tongue or throat so that you cannot swallow or breathe, or really bad itching of the skin with raised lumps)
your skin starts going red and blistering or peeling
fast, uneven heartbeat and fainting (this could mean a life-threatening condition called Torsades de Pointes)
any combination of the following symptoms: high fever, agitation, confusion, trembling, sweating, diarrhoea (loose poo), fast heartbeat or weird movements of your muscles (this could be serotonin syndrome)
you start having seizures or fits for the first time

Get your parent, family member or friend to take you or go with you to support you and keep you safe on the way. If someone is not able to drive you there, call for an ambulance. Take your medication with you.

Contact your doctor immediately but don't stop taking duloxetine, if you get any of the following symptoms:

your behaviour changes because you feel very happy or over-excited
you experience tiredness, confusion and muscle-twitching (you may have a low blood-level of sodium)
yellowing of the skin or whites of the eyes (these may be signs of hepatitis)
if fits that you have had in the past happen more often
unexplained vaginal bleeding (like an unusual period)

If you are unable to contact your doctor, call NHS 111 for urgent advice.

Side effects and your health

Side effects are more common when you first start taking duloxetine. Many go away as you continue your medicine. If they don’t get better, or if you are worried by them and they are causing you distress, speak to your doctor or pharmacist about them.

Very common side effects of taking duloxetine (affecting more than one in ten people) include:

headache
feeling sleepy
nausea (feeling sick)
dry mouth
constipation (difficulty having a poo)

Common side effects of taking duloxetine (affecting up to one in ten people) include:

loss of appetite
weight loss (some children and young people aged under 18 who took duloxetine had some weight loss at first, but after six months of treatment they went back to normal compared with other people of the same age)
feeling nervous, anxious, restless, agitated or tense
lower sex drive or other sexual problems, including difficulty maintaining an erection (staying hard) and difficulty having an orgasm (coming)
sleep problems, unusual dreams, tiredness or sleepiness
feeling dizzy
feeling sluggish (having low energy)
uncontrollable shaking movements or feeling numb
blurred eyesight
feeling your heartbeat pumping in your chest, or higher blood pressure
sweating more and feeling flushed
indigestion, being sick, constipation or diarrhoea, stomach pain, or passing wind more often

There are other side effects that you can get when taking this medicine. We have only included the most common ones here.

This list of side effects can look scary. You may not experience any of them, but it’s important to be aware of them so you know what to do if they do happen.

Unless your side effects are very severe or distressing, try to continue taking your medication until you can talk to your doctor. Your doctor can make changes to your medication to help if needed.

An uncommon but important side effect to be aware of includes thoughts of harming yourself or taking your own life. This may be a symptom of your illness, including depression, but may be a side effect of medication.

If you experience these thoughts, contact your doctor to seek immediate support to keep you safe.

Your doctor will make sure you are monitored carefully for these side effects, and you should decide with your doctor what to do if you experience these feelings while taking duloxetine. It’s a good idea to write these plans down and keep them somewhere safe.

If you are taking duloxetine and have not talked about this with your doctor, go back to them and talk it through. You might also want to talk to your parents, family member or friend about it too.

There is no routine monitoring recommended before starting or while you are taking duloxetine, although your doctor may recommend specific tests, like a blood test, to help them make decisions about your medication.