What is a Patient Information Leaflet and why is it useful?

The Patient Information Leaflet (PIL) is the leaflet included in the pack with a medicine. It is written for patients and gives information about taking or using a medicine. It is possible that the leaflet in your medicine pack may differ from this version because it may have been updated since your medicine was packaged.

Below is a text only representation of the Patient Information Leaflet. The original leaflet can be viewed using the link above.

The text only version may be available in large print, Braille or audio CD. For further information call emc accessibility on 0800 198 5000. The product code(s) for this leaflet is: PL 12762/0596.

Pethidine Injection BP 50mg/ml

Package leaflet: Information for the patient

Pethidine Hydrochloride 50mg/ml Solution for Injection

Pethidine Hydrochloride


Keep this leaflet. You may need to read it again.

If you have any further questions, ask your doctor or pharmacist.

This medicine has been prescribed for you only.

Do not pass it on to others. It may harm them, even if their symptoms are the same as yours.

If you get any side effects talk to your doctor or pharmacist. This includes any possible side effects not listed in this leaflet. See section 4.

The name of your medicine is Pethidine Hydrochloride 50mg/ml Solution for Injection but will be referred to as “Pethidine Injection” throughout the remainder of this leaflet.

What is in this leaflet:

1. What Pethidine Injection is and what it is used for
2. What you need to know before you are given Pethidine injection
3. How Pethidine Injection is given to you
4. Possible side effects
5. How to store Pethidine Injection
6. Contents of the pack and other information


Pethidine 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.

Pethidine Injection is used to relieve moderate to severe pain. Including pain associated with childbirth, or during an anaesthetic or following an operation. As well as relieving pain, pethidine has other effects including a sedative (calming) effect.


You should not be given this medicine if:

  • you know that you are allergic (hypersensitive) to Pethidine Injection or any of the ingredients in this medicine (listed in section 6), or to other strong pain relievers, such as morphine
  • you have any problems that affect your breathing including chronic bronchitis or asthma, shallow breathing or other breathing difficulties
  • you are taking monoamine oxidase inhibitors (MAOIs) or have been taking them within the last two weeks. MAOIs (eg. phenelzine or isocarboxazid) are medicines used to treat depression. (see ‘Taking other medicines)
  • you are suffering from severe headaches or you have recently suffered a head injury,
  • you have any conditions associated with raised pressure in the brain or a tumour of the adrenal gland (phaeochromocytoma).
  • you suffer from alcoholism
  • you suffer from a convulsive disorder (fits) such as epilepsy
  • you are suffering from a condition known as delirium tremens, caused by withdrawal from alcohol
  • your heartbeat is faster than usual
  • you suffer from diabetes.

Patients in a coma should not be given this medicine.

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

Warnings and Precautions

Talk to your doctor or pharmacist before being given Pethidine injection if:

  • you are in shock, the symptoms of which include sweating, a fast pulse and cold, clammy skin
  • you have an underactive thyroid gland (which may cause tiredness, intolerance to cold, constipation, and puffiness of the face)
  • you have underactive adrenal glands (Addison’s disease) or suffer from problems related to your adrenal gland (the organ responsible for stress levels), including adrenocortical insufficiency (a lack of the hormones produced by the adrenal gland)
  • you have a condition that makes you have fits, eg. epilepsy
  • you have problems with your heart causing an increased heart rate
  • you have a problem with your bowel, liver, kidneys or gall bladder
  • you are in a collapsed state from loss of blood or fluid
  • you are feeling weak and run-down
  • you are complaining of headache and vomiting
  • you suffer from sickle cell anaemia
  • you are elderly and in a poor state of health
  • you have an enlarged prostate gland causing difficulty passing water (men only)
  • you have low blood pressure
  • you have weak muscular movement
  • you have diseases of the stomach or intestine
  • you have lung problems
  • you have been drinking alcohol within the previous 24 hours.
  • you are taking any medicine from the group of medicines known as benzodiazepines. Taking these medicines with Pethidine may result in sedation, difficulties in breathing (respiratory depression), coma and may be fatal. Even if benzodiazepines are prescribed, your doctor may need to change the dose, the duration of treatment or monitor you regularly.

If you are elderly or ill, or your baby or child is being given Pethidine Injection, special care will be taken.

If any of the above apply to you or your child, please tell your doctor before being given Pethidine Injection.

Other medicines and Pethidine injection:

Tell your doctor if you are taking or have recently taken any other medicines, including medicines obtained without a prescription.

Pethidine Injection must not be used with drugs used to treat severe depression, such as rasagiline or moclobemide or if you are within 2 weeks of discontinuing them.

A large number of drugs can interact with Pethidine Injection which can significantly alter their effects.

These drugs include:

  • medicines for depression (eg. tricyclic antidepressants such as amitriptyline) and medicines for anxiety (anxiolytics) (eg. benzodiazepines such as diazepam)
  • medicines used to help you to sleep (hypnotics)
  • medicines for schizophrenia or other serious mental illness, such as phenothiazines (which may be present in various medicines including some for treating allergic disorders, nausea (feeling sick) and vomiting (being sick)
  • CNS depressants (drugs that act on the brain and make you feel drowsy or faint). These include sleeping pills, antihistamines (medicines used to treat allergies) that make you drowsy, medicines used to treat certain mental disorders.
  • sedatives, sleeping tablets or barbiturates (eg. phenobarbitone for epilepsy)
  • cimetidine (for heart burn or stomach ulcers)
  • duloxetin (used to treat depression)
  • domperidone and metoclopramide (used for disorders of the gastrointestinal tract)
  • monoamine oxidase inhibitor A and B (used to treat depression)
  • ritanovir (antiviral), a medicine used to treat HIV
  • pain relievers and other opioid medicines
  • anticholinergic drugs (eg. for a tummy or intestine problem or for a “weak” bladder or as an inhaler for a breathing problem)
  • selegiline, a medicine used to treat Parkinson’s disease
  • phenytoin, a medicine used to treat fits (antiepileptic medicine)
  • isoniazid (used to treat tuberculosis)
  • ciprofloxacin, an antibiotic used to treat a number of bacterial infections
  • mexiletine, a medicine used to treat seriously irregular heartbeats
  • concomitant use of Pethidine and sedative medicines such as benzodiazepines or related drugs increases the risk of drowsiness, difficulties in breathing (respiratory depression), coma and may be life-threatening. Because of this, concomitant use should only be considered when other treatment options are not possible.

However, if your doctor does prescribe Pethidine together with sedative medicines the dose and duration of concomitant treatment should be limited by your doctor.

Please tell your doctor about all sedative medicines you are taking and follow your doctor’s dose recommendation closely. It could be helpful to inform friends or relatives to be aware of the signs and symptoms stated above. Contact your doctor when experiencing such symptoms.

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

Pethidine Injection with food, drink and alcohol:

You must avoid drinking alcohol whilst being given Pethidine Injection as it may increase the risk of developing breathing problems and low blood pressure.

Pregnancy, breast-feeding and fertility:

If you are pregnant or breast-feeding, think you may be pregnant or are planning to have a baby, ask your doctor or pharmacist for advice before using this medicine.

As with all drugs Pethidine Injection should only be given in pregnancy if absolutely necessary. Pethidine can pass into your baby either through your blood (during pregnancy and labour) or through your breast milk. Pethidine Injection may cause breathing problems in newborns.

Driving and using machines:

Pethidine Injection can cause drowsiness and clouding of consciousness which could interfere with your ability to use machines. Do not operate machinery whilst you are taking this medicine.

When your Pethidine Injection treatment has stopped, ask your doctor when it will be safe for you to use machines.

The medicine can affect your ability to drive as it may make you sleepy or dizzy.

  • Do not drive while taking this medicine until you know how it affects you.
  • It is an offence to drive if this medicine affects your ability to drive.
  • However, you would not be committing an offence if:
    • The medicine has been prescribed to treat a medical or dental problem and
    • You have taken it according to the instructions given by the prescriber or in the information provided with the medicine and
    • It was not affecting your ability to drive safely

Talk to your doctor or pharmacist if you are not sure whether it is safe for you to drive while taking this medicine.

Tolerance and dependence:

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

Important information about some of the ingredients of Pethidine Injection:

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


Pethidine Injection may be administered by injection into a muscle (intramuscular), or into the tissue just below the skin (subcutaneous) or by slow injection into the vein (intravenous).

Your doctor will choose the most suitable dose depending on your age and your particular condition.

Use in Adults:

A single dose of between 25 - 100mg may be injected into a muscle or into the tissue just beneath the skin. For injection into a vein, a single dose of between 25 - 50mg may be given slowly. These single doses should not usually be repeated more frequently than every 4 hours if required.

Use in Elderly Patients or for Patients in a Weakened Condition:

The initial dose should not exceed 25mg, because elderly patients or those in a weakened condition are more sensitive to the unwanted effects of pethidine.

Use in Children:

The usual single dose is 0.5 to 2.0mg per kilogram of body weight by injection into a muscle. If necessary, this dose may be repeated, allowing at least 4 hours between doses.

To ensure that the correct dose is given, use of a special syringe with fine markings is recommended for administration in children.

Alternatively, the solution may be diluted in Water for Injections to make it easier to measure the dose accurately.

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 Pethidine Injection than you should:

The symptoms and signs of taking too much of this medicine include shallow breathing, drowsiness, incoordination, coma, seizures, blue skin and lips, eye closure (miosis), shaking, cold, clammy skin, drop in body temperature, slow heartbeat and low blood pressure.

This medicine will be given to you in hospital so it is unlikely you will receive too much. Your doctor has information on how to recognise and treat an overdose.

If you feel unwell after being given this medicine, or are at all concerned you have been given too much, tell your doctor or nurse immediately.

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

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


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

Repeated use of pethidine can result in tolerance and addiction

These are more common when Pethidine is given into a vein. All medicines can cause allergic reactions although serious allergic reactions are rare. Any sudden wheeziness and tightness of the chest, difficulty in breathing, swelling of the eyelids, face or lips, skin lumps or hives, skin rash (red spots) or itching (especially affecting your whole body), fever and collapse should be reported to a doctor immediately.

The most serious side effects are difficulty breathing and low blood pressure.

Other side effects that may occur include:

Not known (frequency cannot be estimated from the available data):

  • disturbances in eyesight
  • pin-point pupils
  • delay in blinking reflex when things are close to your eye
  • feeling sleepy
  • weakness, headache,
  • fits
  • CNS excitation
  • a feeling of dizziness or spinning
  • fainting
  • hallucinations (seeing or hearing things that are not there)
  • addiction
  • confusion
  • mood changes (symptoms include feeling tense and restless)
  • flushing of the face,
  • itch, rash, wheals (raised, itchy area of skin),
  • pain, and redness or itching over site of injection
  • difficulty in passing urine and swelling over the body especially on legs
  • feeling restless or agitated
  • trembling, uncoordinated movements
  • dry mouth, constipation, abdominal pain
  • spasms in the lower abdomen
  • also in elderly patients there is an increased risk of delirium (confusion, slurred speech and hallucinations).
  • irregular heartbeats, fast or slow
  • palpitations (an irregular heart rhythm or missed beats)
  • lightheadedness
  • feeling sick (nausea), being sick (vomiting), sweating
  • rapid changes in the blood pressure
  • feeling faint on standing up from a seated
  • slowed breathing
  • low blood pressure, the symptoms of which include feeling dizzy or light-headed, feeling weak and fainting
  • high blood pressure
  • dilatation of blood vessels (vasodilatation)
  • increased or decreased body temperature
  • overactive reflexes
  • feeling overly happy (euphoria) or overly sad (dysphoria)
  • anxiety, nervousness
  • reduced sex drive
  • difficulty achieving or maintaining an erection
  • hypothermia, the symptoms of which include shivering, drowsiness and feeling weak
  • muscle twitching.

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.

Reporting of side effects

If you get any side effects, talk to your doctor or pharmacist or nurse. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via

Yellow Card Scheme
Website: www.mhra.gov.uk/yellowcard

or search for MHRA Yellow Card in the Google Play or Apple App Store. By reporting side effects you can help provide more information on the safety of this medicine.


Keep this medicine out of the sight and reach of children.

Do not use this medicine after the expiry date which is stated on the carton and ampoule label after ‘Exp Date’. The expiry date refers to the last day of that month.

Do not store above 25°C. Keep the ampoules in the outer carton in order to protect from light.

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

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


The active substance is pethidine hydrochloride.

The other ingredients are sodium hydroxide or dilute hydrochloric acid in water for injections BP.

What Pethidine Injection looks like and contents of pack:

Pethidine Injection is a clear, colourless, sterile solution. Each 1ml of solution contains 50mg of pethidine hydrochloride.

The solution is presented in clear glass ampoules (bottles), containing either 1ml or 2ml. The ampoules are then packed in cardboard cartons with 10 ampoules per box.

Marketing authorisation holder:

Mercury Pharmaceuticals Limited
Capital House
85 King William Street


B. Braun Melsungen AG
Mistelweg 2, 12357

This leaflet was last revised in December 2018.