1 Star2 Stars3 Stars4 Stars5 Stars (No Ratings Yet)

Fentanyl Injection (Fentanyl Citrate)

Last updated on: November 22nd, 2021

Fentanyl Injection 50micrograms/ml. Fentanyl citrate

What Fentanyl Injection is and what it is used for

Fentanyl Injection is a type of medicine called an opioid analgesic. The word opioid means a substance similar to opium, for instance strong pain relievers such as morphine or codeine. An analgesic is a medicine that can be used to relieve pain. In low doses, Fentanyl Injection is used to provide pain relief during short surgical procedures and as a medicine given before administration of an anaesthetic.  In higher doses, Fentanyl Injection is used to provide pain relief in patients whose breathing needs to be assisted during surgery.

Before you are given fentanyl injection

You should not be given this medicine if:

  • you know that you are allergic to Fentanyl Injection or one of the other ingredients in this product (listed at the end of this leaflet), or to other strong pain relievers, such as morphine
  • you have any problems that affect your breathing including obstructive airways disease like chronic bronchitis or emphysema or respiratory depression (reduced respiratory rate)
  • after surgery on the biliary tract.

Speak to your doctor if one of these applies to you before you are given this medicine.

Take special care and tell your doctor if:

  • your blood pressure is abnormally low, or you have an underactive thyroid gland (which may cause tiredness, intolerance to cold, constipation and puffiness of the face)
  • you have a condition that makes you have fits, eg. epilepsy
  • you have a problem with your liver, lungs or kidneys
  • you have any kind of heart disease (eg. abnormalities of heart rate or rhythm, heart blocks, inadequate blood supply to heart)
  • you suffer from myasthenia gravis, where your body’s immune system fights its own body
  • you are dehydrated or have had any recent bleeding
  • you have a problem with blood circulation in your brain
  • you have a problem with alcohol or have taken alcohol within the previous 24 hours
  • low blood volume
  • if you are elderly or weak due to ill health
  • if administered during labour, Fentanyl Injection may affect the baby’s breathing.

In certain cases, your doctor may need to monitor your heart with an electrocardiogram (ECG) before starting or during treatment with Fentanyl Injection. Speak to your doctor if one of these applies to you before you are given this medicine.

Taking other medicines

Tell your doctor before you are given this medicine if you are taking or have recently taken any other medicines, including medicines obtained without a prescription. A large number of drugs can interact with Fentanyl Injection which can significantly alter their effects. These drugs include:

  • medicines for anxiety or to help you sleep (eg benzodiazepines such as diazepam or midazolam).
  • medicines used to treat HIV infection such as ritonavir.
  • phenytoin or phenobarbital (to treat epilepsy).
  • other strong medicines for pain called ‘opioid analgesics’ such as morphine or codeine.
  • medicines for treating a fungal infection such as itraconazole, fluconazole or voriconazole.
  • medicines for stomach ulcer eg. cimetidine.
  • medicines used as antipsychotics and prevent vomiting eg. droperidol.
  • beta-blockers (blood pressure lowering medicine)
  • medicines for treatment of depression e.g.monoamine-oxidase Inhibitors (MAOI)
  • medicines used in surgery such as halothane, etomidate (anaesthetic agents) and suxamethonium, vecuronium (muscle relaxants)’.

If you are already taking one of these medicines, speak to you doctor before you receive Fentanyl Injection.

Taking Fentanyl Injection with food and drink

You must tell your doctor if you drank a lot of alcohol within 24 hours before you are given Fentanyl Injection, or are planning to drink a lot of alcohol after you have been given this injection.

Pregnancy and breast-feeding

Tell your doctor before you are given this medicine if you are pregnant, think you may be pregnant or are planning to become pregnant, or are breast-feeding. There is no evidence of harmful effects in pregnancy. However, as with all drugs Fentanyl Injection should only be given in pregnancy if absolutely necessary. You should not be given Fentanyl Injection, if you are in labour or if you are breast-feeding. Do not breast-feed within 24 hours of treatment.

Driving and using machines

Fentanyl Injection can cause drowsiness and clouding of consciousness which could interfere with your ability to drive or to use machines. Do not drive or operate machinery whilst you are taking this medicine. When your Fentanyl Injection treatment has stopped, ask your doctor when it will be safe for you to drive or use machines.

Tolerance and dependence

Fentanyl Injection can become less effective with repeated use. This is called tolerance and it means that the dose may have to be increased for Fentanyl Injection to remain effective. If Fentanyl Injection is used repeatedly, it becomes habit-forming. This is called dependence and if Fentanyl Injection treatment is suddenly stopped, unpleasant withdrawal symptoms may occur.

Important information about some of the ingredients of Fentanyl Injection

This medicine contains less than 1mmol sodium (23mg) per dose, i.e. is essentially ‘sodium-free’.


How Fentanyl Injection is given to you

Fentanyl Injection may be administered by injection into a muscle or by injection or infusion into the vein.

Your doctor will choose the most suitable dose for your particular condition.  Doses greater than 200micrograms are only for use in anaesthesia, as higher doses may cause difficulty in breathing.

If you have any further questions on the use of this product, ask your doctor or pharmacist.

If you think you have been given more Fentanyl Injection than you should have.

If you think that you have been given too much of this medicine, tell your doctor immediately.

If you think you have missed a dose of Fentanyl Injection.

If you think that you have missed a dose, tell your doctor, nurse immediately.

Possible side effects

Like all medicines, Fentanyl Injection can sometimes cause side-effects, although not everyone gets them.

All medicines can cause allergic reactions although serious allergic reactions are rare.

Any sudden wheeziness, difficulty in breathing, swelling of the eyelids, face or lips, rash or itching (especially affecting your whole body) should be reported to a doctor immediately.

Very common

(affects more than 1 in 10 people)

  • Feeling sick (nausea), being sick (vomiting),
  • Muscle stiffness (which may involve your chest muscles)


(affects less than 1 in 10 people)

  • Agitation
  • Involuntary, repetitive body movements
  • Drowsiness
  • Dizziness
  • Problems with vision
  • Rapid or slow heartbeats
  • Low or high blood pressure
  • Pain in your veins
  • Choking caused by cramping (spasm) of the muscles in your throat
  • Difficulty in breathing or wheezing
  • Stop breathing for a short period of time (apnoea).
  • Skin rash
  • Confusion after the operation


(affects less than 1 in 100 people)

  • Changes in blood pressure
  • Breathing complications
  • Breathing faster than normal
  • Fall in body temperature below normal or chills
  • Headache
  • Swelling and clotting in a vein
  • Hiccups
  • Mood elevation

Other side effects

(frequency not known):

  • Convulsions (fits or seizures)
  • Loss of consciousness
  • Muscle twitching
  • Stopping of the heart (cardiac arrest)
  • Slow or shallow breathing
  • Itching of the skin

If you received Fentanyl Injection with a tranquiliser (such as droperidol) and you notice any of the following effects, tell your doctor:

  • Shivering and restlessness
  • Seeing or hearing things that aren’t there (hallucinations)
  • Unusual movements, including trembling and shaking of the hands and fingers, twisting movements of the body, shuffling walk and stiffness of the arms and legs

If any of the side effects gets serious, or if you notice any side effects not listed in this leaflet, please tell your doctor or pharmacist.


How to store fentanyl injection

Keep out of the reach and sight of children.

The product should not be used after the expiry date printed on the ampoule or carton.

Fentanyl Injection should be protected from light and stored below 25°C

If only part of the contents of an ampoule is used, the remaining solution should be discarded.

For single use only.

Further information

The active substance is fentanyl citrate.

The other ingredients are sodium chloride BR sodium hydroxide and water for injections BR

What Fentanyl Injection looks like and contents of pack

Fentanyl Injection is a clear, colourless, sterile solution. Each 1ml of solution contains 50mcg of fentanyl citrate.

The solution is presented in clear glass ampoules (bottles), containing either 2ml or 10ml. The ampoules are then packed in cardboard cartons with 10 ampoules per box.

This leaflet was last revised in: November, 2010.

Leave a Reply
Notify of