Pethidine Side Effects

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Answer the side-effect intent for pethidine without diagnosing; distinguish common from serious reactions and give safe next-step/reporting guidance.

What is pethidine?

Pethidine contains the active ingredient Pethidine Hydrochloride.

• Active ingredient — Pethidine Hydrochloride
• Registration number — 27/2.9/0424; 27/2.9/0425
• Registration holder — Unimed Healthcare (Pty) Ltd

It is approved for:

• Relief of pain
• It Is particularly useful for the control and relief of pain after you have had an operation
• It may be used when you are in labour for the relief of labour pains

Common side effects of pethidine

Not everyone gets side effects. The effects below are those listed in the South African approved leaflet, grouped using the leaflet’s own frequency wording.

Reported side effects

• swelling of the hands, feet, ankles, face, lips and mouth or throat which may cause difficulty in swallowing or breathing
• rash or itching
• fainting
• These are all very serious side effects. If you have them, you may have had a serious allergic reaction to PETHIDINE UNIMED. You may need urgent medical attention or hospitalisation. Tell your doctor immediately or go to the casualty department at your nearest hospital if you notice any of the following:
• chest pain, angina, changes in the way your heart beats, for example, if you notice it beating faster, difficulty breathing
• signs of recurrent infections such as fever or sore throat
• less urine than is normal for you
• yellowing of the skin and eyes, dark urine, and tiredness which may be symptoms of liver problems
• These are all serious side effects. You may need urgent medical attention. Tell your doctor if you notice any of the following: Side effects with frequency unknown:
• addiction
• confusion
• mood changes (symptoms include feeling tense and restless)
• feeling of intense happiness (euphoria)
• hallucinations (seeing or hearing things that aren’t real)
• dizziness
• drowsiness
• restlessness
• tremor or involuntary shaking
• convulsions
• feeling faint on standing up from a seated position
• headache
• fainting
• feeling weak
• a fast or slow heartbeat
• dry eye
• pin-point pupils, corneal reflex decreased
• a feeling of dizziness or spinning
• palpitations (an irregular heart rhythm or missed beats)
• low blood pressure, the symptoms of which include feeling dizzy or light-headed, feeling weak and fainting
• high blood pressure
• feeling sick (nausea)
• being sick (vomiting)
• constipation
• dry mouth
• facial flushing
• sweating
• slowed breathing
• spasms in the lower abdomen
• a red, itchy rash
• muscle twitching
• difficulty in passing urine
• reduced sex drive
• difficulty achieving or maintaining an erection
• hypothermia, the symptoms of which include shivering, drowsiness and feeling weak
• pain, redness or itching at the injection site

Serious side effects and warning signs

This leaflet does not set out a separate list of serious side effects. The general warning signs below apply to any medicine.

General warning signs that apply to any medicine

How long can side effects last?

How long a side effect lasts depends on the effect, the product, how long it has been used, and the person. Some effects ease within days as the body adjusts. Others continue for as long as the product is used. A few can persist after stopping, and some need review rather than waiting.

• Settling effects — mild effects that ease over the first days or weeks of use
• Ongoing effects — effects that continue while the product is being used and improve after stopping
• Persistent effects — effects that continue after stopping and need medical review
• Delayed effects — effects that appear after weeks or months rather than immediately

Which of these applies to a particular effect is a clinical question. If a side effect is not settling, is getting worse, or is affecting your daily life, that is worth a conversation with a pharmacist or doctor regardless of how long it has been going on.

Factors that may affect side effects

The approved leaflet identifies the following cautions and factors.

Do not use it at all if

• if you are hypersensitive (allergic) to pethidine hydrochloride or to any of the ingredients of PETHIDINE UNIMED (listed in section 6)
• if you are suffering from breathing difficulties or if you are having an asthma attack
• if you suffer from heart failure (when your muscles does not pump blood as well as it should) that resulted from lung disease
• if you are suffering from severe headaches or have suffered a head injury
• if you suffer from alcoholism
• if you suffer from a convulsive disorder (fits) such as epilepsy
• if you suffer from a tumour of the adrenal gland known as phaeochromocytoma
• if you are taking medicines known as Monoamine Oxidase Inhibitors (MAOI’s) or within 2 weeks of discontinuation of such treatment
• if you are using antidepressants such as Selective Serotonin Reuptake Inhibitors (SSRIs) and St. John’s wort or pain medication such as tramadol or triptans (used to treat severe headaches/migraines)
• if you are taking a medicine called ritonavir (used to treat HIV infections)
• if you are in a coma
• if you suffer from obstruction of the intestine due to paralysis of the intestinal muscles (paralytic ileus)
• if you suffer from an irregularly fast or erratic heartbeat (arrhythmia) that affects the heart’s upper chambers (supraventricular tachycardia)

Use with care, and tell your doctor, if

• If you suffer from opioid addiction
• If you are in shock (the symptoms of which include sweating, a fast pulse and cold, clammy skin)
• If you suffer from thyroid problems
• If you 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)
• If you suffer from low blood pressure
• If you are a male and suffer from problems with your prostate
• If you suffer from problems with your gallbladder
• If you suffer from problems with your bowel
• If you have weak muscular movement and rapid fatigue of muscles under voluntary control (myasthenia gravis)
• If you have lung problems
• if you have problems with your kidneys or liver
• if you are in labour
• if you are elderly or very ill
• if you or your family have a history of mental health disorders (difficulty in thinking, understanding and judging clearly which causes loss of touch with reality), if you have depression, anxiety and suffer from alcohol and drug abuse. Taking opioids or receiving opioids (as contained in Pethidine Unimed) over a long period of time produces:
• Tolerance (where you develop a requirement for increased doses of Pethidine Unimed to achieve the same pain-relieving effects
• Dependence, such that when people stop taking/receiving opioids, they have physical and psychological symptoms of withdrawal (such as muscle cramping, diarrhoea, and anxiety). Opioid addiction can cause life-threatening health problems, including the risk of overdose. Speak to your doctor if you experience any of these effects or if you are concerned. Children and adolescents Great care should be taken if Pethidine Unimed is given to newborns or babies, as they may be more sensitive to breathing difficulties associated with Pethidine Unimed use

Pregnancy and breastfeeding

• If you are pregnant or breastfeeding, think you may be pregnant or are planning to have a baby, please consult your doctor, pharmacist or other health care provider for advice before taking PETHIDINE UNIMED

Interactions and medicines to check

The approved leaflet names these interactions.

• Pethidine Unimed must not be used with medicines used to treat severe depression, such as rasagiline or moclobemide, or if you are within 2 weeks of discontinuing them. These medicines are known as Monoamine Oxidase Inhibitors (MAOI’s), Tell your doctor if you are taking or have been given the following medicines as PETHIDINE UNIMED can affect how they work:
• Selegiline or rasagiline (medicine used to treat Parkinson’s disease)
• ritonavir (medicine used to treat HIV)
• cimetidine (medicine used to treat stomach ulcers) and cyclizine (medicine used to treat nausea)
• anxiolytics (medicine used to reduce anxiety) eg. benzodiazepines such as diazepam
• hypnotics (medicine used to help you to sleep)
• CNS depressants (medicine that act on the brain and make you feel drowsy or faint). These include sleeping pills, anti-histamines (medicines used to treat allergies) that make you drowsy, medicines used to treat certain mental disorders; alcohol
• phenytoin (medicine used to treat fits)
• phenothiazines (medicines used to treat serious mental disorders)
• medicine for depression (eg. tricyclic antidepressants such as amitriptyline)
• phenobarbitone (medicines used to treat epilepsy sedatives, sleeping tablets or barbiturates)
• domperidone (medicines used to treat disorders of the gastrointestinal tract)
• pain relievers used to treat moderate to severe pain (such as tramadol) and other opioid medicines
• ciprofloxacin (for antibiotic used to treat a number of bacterial infections)
• mexiletine (medicine used to treat seriously irregular heartbeats)
• Citalopram (SSRIS) and St John’s Wort used for the treatment of depression
• Triptans (medicines used for the treatment of migraines). Concomitant use of Pethidine Unimed and sedative medicines such as benzodiazepines or related medicines 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 Unimed together with sedative medicines the dose and duration of concomitant treatment should be limited by your doctor. PETHIDINE UNIMED with Alcohol You are advised not to drink alcohol during your treatment with Pethidine Unimed

What to do if you experience side effects

If you think you are having a side effect, the response depends on how severe it is. Use the warning signs above first — if any of those apply, treat it as urgent.

If the symptom is severe or frightening

Get medical help immediately. Call 10177 for an ambulance, or 112 from a mobile phone, or go to the nearest emergency department. Take the product and its packaging with you if you can.

If the symptom is mild but bothering you

• Write down what the symptom is, when it started, and how it relates to when you take the product
• Check the leaflet that came with the product to see whether the symptom is listed
• Speak to your pharmacist — for many questions this is the fastest route to a useful answer
• Contact the prescriber if the symptom is affecting your daily life or is not settling

You can also report a suspected side effect in South Africa. Reporting does not replace getting medical advice, and you do not need to be certain the product was the cause.

When to seek urgent medical help

Some symptoms need medical attention straight away rather than an appointment in a few days. Do not wait to see whether they settle.

Get same-day medical advice if you have

• A high fever, or a rash together with feeling generally unwell
• Yellowing of the eyes or skin, or unusually dark urine
• Unusual bruising or bleeding that you cannot explain
• Severe or persistent vomiting or diarrhoea, especially if you cannot keep fluids down
• A sudden change in mood, or thoughts of harming yourself
• Any symptom that is rapidly getting worse

How to report a suspected side effect in South Africa

South Africa has an official system for reporting suspected side effects, run by the South African Health Products Regulatory Authority (SAHPRA). Reports from the public and from healthcare professionals are how safety signals get detected after a product is already in use.

Who can report

Anyone can report — you do not have to be a healthcare professional, and you do not need to prove that the product caused the problem. A suspicion is enough. Patients, caregivers and family members can all submit a report.

What to have ready

• The name of the product, its strength and form, and the batch number if you have it
• Why it was being used, and when it was started and stopped
• What the suspected reaction was, when it began, and how long it lasted
• Any other medicines, supplements or remedies being used at the same time
• Basic details about the person affected — age and sex are usually enough

How to report

SAHPRA accepts adverse reaction reports through its e-Services reporting system and through the Med Safety mobile app. Healthcare professionals can also report through the same routes. Current forms and access points are published on the SAHPRA site.

• SAHPRA Health Products Vigilance — the main vigilance and reporting hub
• SAHPRA e-Services — current adverse reaction reporting access

For a fuller walkthrough see how to report an adverse drug reaction.

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