How does it work?
Cymbalta capsules contain the active ingredient duloxetine hydrochloride, which is a type of antidepressant known as a serotonin and noradrenaline reuptake inhibitor (SNRI). This type of medicine acts on nerve cells in the brain.
In the brain there are numerous different chemical compounds called neurotransmitters. These act as chemical messengers between the nerve cells. Serotonin and noradrenaline are two such neurotransmitters and have various functions that we know of.
When serotonin and noradrenaline are released from nerve cells in the brain they act to lighten mood. When they are reabsorbed into the nerve cells, they no longer have an effect on mood. It is thought that when depression occurs, there may be a decreased amount of serotonin and noradrenaline released from nerve cells in the brain.
Duloxetine works by preventing serotonin and noradrenaline from being reabsorbed back into the nerve cells in the brain. This helps prolong the mood lightening effect of any released serotonin and noradrenaline. In this way, duloxetine helps relieve depression.
Duloxetine may also be used in the treatment of generalised anxiety disorder.
It may take between two to four weeks for the benefits of this medicine to appear, so it is very important that you keep taking it, even if it doesn't seem to make much difference at first. If you feel your depression or anxiety has got worse, or if you have any distressing thoughts or feelings in these first few weeks, then you should talk to your doctor.
This medicine is also used to treat nerve pain in the feet, legs or hands that is due to nerve damage caused by poorly controlled diabetes. Duloxetine is thought to enhance the nerve signals within the central nervous sytem that naturally inhibit pain.
What is it used for?
- Depressive illness.
- Generalised anxiety disorder (GAD).
- Nerve pain in the feet, legs or hands due to nerve disease in adults with diabetes (diabetic peripheral neuropathic pain).
- This medicine may make you feel drowsy or dizzy 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. If you do experience drowsiness this may be made worse by alcohol.
- This medicine may cause a drop in blood pressure when moving from a lying or sitting position to sitting or standing, which may cause dizziness, light-headedness or fainting, particularly when you first start treatment. For this reason, you should take care when moving from lying down to sitting or standing, particularly if you wake up in the night, until you know how this medicine affects you. If you feel dizzy or light-headed at any time during treatment, sit or lie down until the symptoms pass.
- 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. This also applies if you are taking this medicine for diabetic nerve pain.
- Duloxetine has not been studied in children. However, in clinical trials of other antidepressants in children and adolescents, suicide attempts, suicidal thoughts and hostility were more frequently observed in those taking antidepressants compared to those treated with placebo (dummy pills). Duloxetine is not licensed and not recommended for any uses in children and adolescents under 18 years of age. However, some specialists may still prescribe it if they feel it is essential. If your child is prescribed duloxetine you should discuss its safety and potential adverse effects with your child's specialist. It is very important that your child is encouraged to report any distressing feelings, thoughts about suicide or self-harm, irritability, aggressive behaviour, mood changes or other unusual change in behaviour that they may experience while taking the medicine. If you notice a change in your child's behaviour or are worried about them at any point it is important to talk to your doctor immediately.
- This medicine has been associated with the development of unpleasant or distressing restlessness and the need to move, often accompanied by an inability to sit or stand still. This is most likely to occur within the first few weeks of treatment. If you experience these symptoms you should consult your doctor.
- This medicine can cause some people's blood pressure to increase. It is recommended that that your blood pressure is monitored while you are taking this medicine if you suffer from heart disease or high blood pressure, especially during the first month of treatment.
- Antidepressants may cause the amount of sodium in the blood to drop - a condition called hyponatraemia. This can cause symptoms such as drowsiness, confusion, muscle twitching or convulsions. Elderly people may be particularly susceptible to this effect. There may also be an increased risk in people with liver cirrhosis and those who are dehydrated or taking diuretic medicines. You should consult your doctor if you develop any of these symptoms while taking this medicine so that your blood sodium level can be checked if necessary.
- You should not suddenly stop taking this medicine, as this may cause withdrawal symptoms such as dizziness, pins and needles sensations, feeling sick, difficulty sleeping, intense dreams, headache, irritability, sweating, diarrhoea, tremor, agitation or anxiety. On very rare occasions some people have experienced withdrawal symptoms after accidentally missing a dose of this medicine. Withdrawal symptoms are temporary and are not the same as addiction. They can usually be avoided by stopping the medicine gradually, usually over at least two weeks. Follow the instructions given by your doctor when it is time to stop treatment with this medicine.
Use with caution in
- Elderly people.
- Young adults.
- People with a history of suicidal thoughts or suicide attempts.
- Bipolar affective disorder (manic depression).
- History of mania.
- History of seizures, eg epilepsy.
- Raised pressure in the eyeball, eg glaucoma or people at risk of glaucoma.
- Heart disease.
- High blood pressure (hypertension).
- People who are dehydrated or taking diuretic medicines.
- People with bleeding tendencies.
- People taking medicine to prevent blood clotting (eg anticoagulants such as warfarin or antiplatelets such as aspirin, clopidogrel or dipyridamole).
- People taking medicines that can have side effects on the liver.
Not to be used in
- Children and adolescents under 18 years of age (but see warning above).
- People with liver disease resulting in decreased liver function.
- Severely decreased kidney function.
- Uncontrolled high blood pressure (hypertension).
- People who have taken a monoamine oxidase inhibitor antidepressant (MAOI) in the last 14 days.
- People taking the medicines fluvoxamine, ciprofloxacin or enoxacin.
- Rare hereditary problems of fructose intolerance, glucose-galactose malabsorption, or sucrose-isomaltase insufficiency (Cymbalta capsules contain sucrose).
This medicine should not be used if you are allergic to one or 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.
- This medicine has not been studied in pregnant women. The risk to a developing baby is unknown, however, if the medicine is used near term it may cause withdrawal symptoms in the baby after birth. This medicine should only be used during pregnancy if the potential benefits to the mother outweigh any potential risks to the foetus. Seek medical advice from your doctor if you get pregnant or plan to get pregnant while you are taking this medicine. If you decide to stop treatment with this medicine you should not do so suddenly - see the warning above about withdrawal symptoms.
- This medicine passes into breast milk, however, the effect of this on a nursing infant is not known. This medicine is not recommended for use by breastfeeding mothers. Seek medical advice from your doctor.
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.
Very common (affect more than 1 in 10 people)
- Feeling sick.
- Dry mouth.
Common (affect between 1 in 10 and 1 in 100 people)
- Decreased appetite and weight loss.
- Difficulty sleeping (insomnia).
- Increased sweating.
- Blurred vision.
- Pins and needles sensations.
- Taste disturbances.
- Awareness of your heartbeat (palpitations).
- Disturbances of the gut, such as abdominal pain, diarrhoea, constipation, indigestion, vomiting, wind.
- Sensation of ringing or other noise in the ears (tinnitus).
- Muscle spasm, pain or tightness.
- Hot flushes.
- Decreased sex drive or impotence (erectile dysfunction).
- Anxiety or agitation.
- Abnormal dreams.
Uncommon (affect between 1 in 100 and 1 in 1000 people)
- Weight gain.
- Increase in blood pressure or heart rate.
- Increase in blood sugar (hyperglycaemia), particularly in people with diabetes.
- Visual disturbances, dilated pupils.
- Difficulty passing urine.
- Cold hands or feet.
- Feeling hot or cold.
- Feeling thirsty.
- Problems with ejaculation.
- Drop in blood pressure when moving from a lying or sitting position to sitting or standing, which may cause dizziness, light-headedness or fainting.
- Disturbance in attention.
- Disturbance in taste.
- Poor sleep quality.
- Muscle twitching, restless legs syndrome.
- Throat tightness.
- Increased tendency to bruise.
- Abnormal reaction of the skin to sunlight (photosensitivity).
- Inflammation of the liver (hepatitis).
Rare (affect between 1 in 1000 and 1 in 10,000 people)
- Increased blood cholesterol level.
- Abnormal heart rhythms.
- Anger and aggression.
- Breath odour.
- Underactive thyroid gland.
See also the warning section above. The side effects listed 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.
This medicine must not be taken at the same time as, or within two weeks of taking a monoamine oxidase inhibitor (MAOI) antidepressant such as phenelzine, tranylcypromine or isocarboxazid. Conversely, an MAOI should not be started until at least five days after stopping duloxetine. This is because using these medicines together can cause a serious and potentially life-threatening interaction.
The antidepressant moclobemide is not recommended for use in combination with this medicine. Other antidepressants should only be used with caution.
Side effects may be more common if the herbal remedy St John's wort (Hypericum perforatum) is used in combination with this medicine. This combination is also not recommended.
The following medicines must not be taken in combination with duloxetine, as they increase the blood level of duloxetine and may increase the risk of its side effects:
This medicine should not be used at the same time as a medicine called Yentreve, which also contains duloxetine, but is used for urinary incontinence.
There may be an increased risk of drowsiness or sedation if this medicine is taken with any of the following medicines (which can also cause drowsiness):
- antipsychotics, eg haloperidol, chlorpromazine
- barbiturates, eg phenobarbital, amobarbital
- benzodiazepines, eg diazepam, temazepam
- sedating antihistamines, eg chlorphenamine, hydroxyzine
- sleeping tablets, eg zopiclone
- strong opioid painkillers, eg morphine, codeine.
There may be an increased risk of a rare side effect called the serotonin syndrome if duloxetine is taken with any of the following medicines, which also enhance the activity of serotonin in the central nervous system:
- sibutramine (not recommended in combination with this medicine)
- SSRI antidepressants, eg fluoxetine, paroxetine
- the herbal remedy St John's wort (Hypericum perforatum)
- tricyclic antidepressants such as clomipramine or amitriptyline
- triptans for migraine, eg sumatriptan
There may be a increased risk of bleeding if this medicine is taken in combination with any of the following medicines, which reduce the ability of the blood to clot:
- anticoagulants (to prevent and treat blood clots) such as warfarin
- antiplatelet medicines (to "thin the blood") such as aspirin, dipyridamole or clopidogrel
- non-steroidal anti-inflammatory drugs (NSAIDs) eg ibuprofen, diclofenac, naproxen.
There may be an increased risk of side effects on the liver if this medicine is taken in combination with medicines that can affect the liver.
Duloxetine may increase the blood levels of the following medicines:
- tricyclic antidepressants such as nortriptyline, amitriptyline, and imipramine.
Other medicines containing the same active ingredient
In the UK there are currently no other medicines for treating depression that contain duloxetine as the active ingredient.
Yentreve contains duloxetine, but is not used to treat depression.