December 2021

What is Duloxetine?

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Duloxetine can be used to treat different types of chronic pain.  Duloxetine belongs to the group of medicines called Serotonin Noradrenergic

Reuptake Inhibitors (SNRI) that are also used to treat depression.  Duloxetine works by increasing the amount of specific nerve transmitters in the nervous system, this then reduces the pain messages arriving in the brain.


What benefit can you expect from your treatment?

Duloxetine is used to reduce pain in fibromyalgia and neuropathic (nerve) pain.  This means it is especially good at reducing sensations such as hot, burning, throbbing, shooting, stabbing, sharp, cramping, aching, tingling, numbness, pins and needles pain and for pain that keeps you awake at night.

You may feel a slight effect after a week but it may take up to two months to feel the full effect. The dose may need to be increased to gain maximum effect; your doctor will advise you regarding this.  Duloxetine does not always work for everyone, however if you do not feel any benefit from this medication, do not stop it suddenly, speak to your doctor first.

How is duloxetine taken?

The capsules should be swallowed whole with water on an empty stomach.

When should it be taken?

It is recommended duloxetine is taken once a day (usually in the morning with food is best), at about the same time each day.  Taking it at the same time each day will have the best effect and help you remember to take it.

What is the dosage?

Duloxetine comes in different strength capsules. A typical starting dose is 30 to 60 mg taken once a day.

Can other medicines be taken with duloxetine?

Duloxetine can interact with other medicines, e.g. warfarin, tramadol and herbal products.  Always tell your doctor, nurse or pharmacist which other medicines you are taking or buying, so they can make sure there are no interactions between your medicines.

How long is the treatment continued?

Treatment with duloxetine is continued indefinitely as long as it is effective and as long as no serious side effects occur.

If you stop duloxetine treatment for more than a few weeks there is a risk that your condition may get worse. Continue with your treatment unless advised by your doctor or unless side effects develop.

Are there any side effects?

You might experience side effects with your treatment. Tell your doctor if you are concerned about possible side effects.

A reduction in dose may minimise side effects so that you can continue to take the treatment. Your doctor will advise on any dose changes that are necessary.

Most common possible side effects

The most common side effects for this medicine are;

  • Pain in the stomach, nausea or vomiting and constipation
  • Dry mouth
  • Dizziness

Duloxetine can also cause trouble sleeping (insomnia) in some people but in other people it can cause drowsiness. It is recommended that you take duloxetine in the morning with food when you first start taking it.  If you find that it makes you sleepy during the day you can move it to night with food.

If you experience any other side effects (anything unusual for you within a few days of starting the medicine) you should stop taking duloxetine and inform your doctor.

Less common or rare possible side effects

Contact your doctor if you experience one of these

  • Blurry vision – Duloxetine can cause blurry vision. Patients should tell their doctor if they have glaucoma before starting this medicine.
  • Blood pressure – Duloxetine can rarely cause an increase in blood pressure. Doctors will monitor this. Patients should tell their doctor if they have high blood pressure.
  • Increased sweating – Duloxetine can rarely cause an abnormal increase in sweating.
  • Headache – Duloxetine can rarely cause a headache.
  • Bladder problems – Duloxetine can cause urine retention and difficulty voiding.
  • Liver failure, yellowing of the skin or whites of the eyes (jaundice)
  • Serious allergic reaction which causes difficulty in breathing or dizziness with swollen tongue or lips.

More information about possible side effects

Information that comes with your duloxetine medicine describes in detail potential serious side effects that may occur with duloxetine.

What precautions are necessary?

Blood tests

Patients who take duloxetine should get occasional blood tests as requested by their doctor. It is important make sure duloxetine isn’t affecting the liver.

Use with alcohol

Drinking alcohol while taking duloxetine is not recommended because they can both effect the liver. Patients are advised to avoid alcohol completely, or at the very least, substantially limit the amount of alcohol that they drink.

How to store duloxetine

  • Keep your capsules in a cool dry place where the temperature stays below 25°C.  Do not store duloxetine or any other medicine in the bathroom or near a sink. Do not leave it on a windowsill or in the car on hot days. Heat and dampness can destroy some medicines.
  • Keep it where children cannot reach it. A locked cupboard at least one-and-a-half metres above the ground is a good place to store medicines.
  • Do not throw away any medicines via wastewater or household waste. Ask your pharmacist how to throw away medicines you no longer use.