Fentanyl Side Effects

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

What is fentanyl?

Fentanyl contains the active ingredient Fentanyl.

• Active ingredient — Fentanyl
• Registration number — 44/2.9/0757; 44/2.9/0758; 44/2.9/0759; 44/2.9/0760
• Registration holder — Sandoz SA (Pty) Ltd

It is approved for:

• FENDERMAL belongs to a group of strong painkillers called opioids
• The painkiller, fentanyl, slowly passes from the patch, through the skin and into the body
• : : : Transdermal patches (matrix) PR FENDERMAL relieves severe long-lasting pain, which can only adequately be managed with strong painkillers (opioids)

Common side effects of fentanyl

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

• Hives, difficulty breathing, swelling of your face, lips, tongue, or throat, severe irritation, reddening or blistering of your skin. If any of the following happens, stop taking FENDERMAL and tell your doctor immediately or go to the casualty department at your nearest hospital:
• Feeling unusually drowsy, breathing that is more slow or shallow than expected. Follow the advice above and keep the person who was wearing the patch moving and talking as much as possible. Very rarely these breathing difficulties can be life-threatening or even fatal, especially in people who have not used strong opioid painkillers (like FENDERMAL or morphine) before
• Fits (seizures)
• Reduced consciousness or loss of consciousness
• These are all very serious side effects. If you have them, you may have had a serious reaction to FENDERMAL. You may need urgent medical attention or hospitalisation. Consult your doctor if any of the following side effects continue or are bothersome and occur frequently:
• Allergic reaction : : : Transdermal patches (matrix)
• Loss of appetite
• Difficulties in sleeping
• Hallucinations (seeing or hearing things that are not there)
• Depression
• Feeling anxious or confused
• Sleepiness, nervousness, weight loss
• Headache
• Feeling dizzy
• Pins and needles (paraesthesia)
• Muscle tremors
• Spinning sensation (vertigo)
• Heartbeat feels fast or uneven (palpitations, tachycardia)
• High blood pressure
• Difficulties in breathing, shortness of breath
• Nausea, vomiting, constipation, dry mouth, heartburn
• Diarrhoea
• Stomach pain
• Increased sweating, itching (itching will usually disappear within one day after the patch has been removed)
• Skin rash, skin reddening
• Muscle spasms
• Difficulties in passing urine
• Swollen hands, ankles or feet (peripheral oedema)
• Feeling very tired, weak or generally unwell
• Feeling cold Less frequent side effects that may occur include the following:
• An exaggerated feeling of well-being (feeling “high”), memory loss
• Feeling agitated or disoriented : : : Transdermal patches (matrix)
• Speech disorders, excessive anxiety or fear
• Convulsions (fits)
• Being uncertain about your surroundings, becoming unconscious
• Decreased feeling or sensitivity, especially in the skin (hypoesthesia)
• Fall in blood pressure
• Dilation of the blood vessels (you may notice reddening of the skin)
• Slow heart rate
• Blue colour to the skin caused by low oxygen in the blood (cyanosis)
• Breathing problems, including asthma
• Being unable to breath
• Stopping breathing from time to time (apnoea)
• Severe spasmodic pain owing to the lack of movement of the intestines (ileus)
• Skin condition with itching, redness and a burning feeling (eczema) or other skin disorders including dermatitis
• Skin reactions at the attachment site
• Muscle twitching
• Disturbances in vision
• Blurred vision
• Constricted pupils (miosis)
• Difficulty getting and keeping an erection (impotence) or problems having sex
• Flu-like illness
• Feeling of body temperature change
• Fever
• Abdominal pain, including inflamed and irritated pancreas Side effects that have been reported with frequency unknown:
• Lack of male sex hormones (androgen deficiency)
• Delirium (symptoms may include a combination of agitation, restlessness, disorientation, confusion, fear, seeing or hearing things that are not really there, sleep disturbance, nightmares)
• Loss of coordination : : : Transdermal patches (matrix)
• Reduced vision in one eye (lazy eye)
• Irregular heartbeat (dysrhythmia)
• Abnormally slow breathing rate
• Hiccups
• Pain when passing wind
• Passing less urine than normal
• Pain in the bladder
• Tolerance (a condition that occurs when the body gets used to the medicine so that either more medicine is needed, or different medicine is needed)
• You can become dependent on FENDERMAL FENDERMAL with antidepressants The risk of side effects increases if you are taking medicines such as certain antidepressants. FENDERMAL may interact with these medicines and you may experience changes to mental status such as feeling agitated, seeing, feeling, hearing, or smelling things that are not there (hallucinations) and other effects such as changing blood pressure, fast heartbeat, high body temperature, overactive reflexes, lack of coordination, muscle stiffness, nausea, vomiting and diarrhoea. If you have been using FENDERMAL for some time, it might happen that FENDERMAL will become less effective for you so that a dose adjustment will be necessary (tolerance may develop). Physical and psychological dependence may develop as well and you might experience withdrawal symptoms, if you do suddenly stop using the patches. Withdrawal symptoms may be nausea, vomiting, diarrhoea, anxiety and shivering. 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

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 fentanyl, or any of the other ingredients of FENDERMAL (listed in section 6)
• If you suffer from pain which lasts only for a short period (e.g. after a surgical procedure) or if the pain is mild and can be managed with less potent painkillers
• If you have difficulty breathing
• If you have a slow heartbeat and a disturbance in your heart rhythm
• If you are pregnant, planning to become pregnant or breastfeeding your baby
• FENDERMAL transdermal patches may not be used on children less than 12 years of age
• If you have severe or uncontrolled asthma
• If your central nervous system is severely impaired, e.g., by brain injury. Certain medicines can cause undesired effects when used together with FENDERMAL. Such medicines have the potential to affect your breathing, blood pressure, and may lead to coma. These include medicines used to treat allergies, medicines used to treat muscle pain (muscle relaxants), medicines used for the treatment of sleeplessness as well as alcoholic beverages and other medicines as listed in the section “Other medicines and FENDERMAL”

Use with care, and tell your doctor, if

• Asthma, breathing difficulties or any lung disease. If you experience difficulty breathing, remove the FENDERMAL patch immediately and get medical assistance
• Low blood pressure
• Problems with your liver
• Kidney problems
• If you have had a head injury, brain tumour, headache, visual disturbances, changes in your state of consciousness or loss of consciousness or coma
• Slow irregular heartbeat
• Myasthenia gravis; if you suffer from a disease causing weakness of the muscles and fatigue (tiredness)
• If you have ever abused or been dependent on alcohol, prescription medicines or illegal drugs. Abuse or intentional misuse of FENDERMAL may result in overdose and/or death
• If you are taking or have recently taken certain medicines for depression called Selective Serotonin Reuptake Inhibitors (SSRIs), Serotonin Noradrenaline Re-uptake Inhibitors (SNRIs) or Monoamine Oxidase Inhibitors (MAOIs), as they may increase the risk of a condition called serotonin syndrome. FENDERMAL may make you unusually drowsy, as well as making your breathing slower or shallow. Very rarely these breathing problems can be life-threatening or even fatal, especially in people who have not used strong opioid painkillers (like FENDERMAL or morphine) before. If you, or your partner or carer, notice that the person wearing the patch is unusually drowsy, with slow or shallow breathing:
• Take the patch off
• Call a doctor, or go to your nearest hospital straight away : : : Transdermal patches (matrix)
• Keep the person moving and talking as much as possible Increased body temperature may cause too much medicine to pass through the skin. Therefore:
• Inform your doctor if you develop a fever during treatment
• Avoid exposing the patch on the skin to direct heat such as electric blankets, hot-water bottles, solarium (sunroom) or hot baths
• You may stay outside in the sun, but you must protect the patch with a piece of clothing during hot summer days
• Remove the patch before you take a sauna. Using a sauna is only possible when replacing a transdermal patch. A new patch should be applied to cool dry skin
• Avoid excessive/strenuous exercise. Decreasing relief of pain (tolerance), physical or psychological dependence may develop if you use FENDERMAL for a longer period. If you are an elderly patient or if you suffer from an illness causing ongoing muscle loss (e.g. myasthenia gravis, cancer, AIDS, heart failure or advanced chronic obstructive pulmonary disease (COPD)) your doctor will monitor you more carefully, because it may be necessary to prescribe a lower dose. FENDERMAL may cause constipation. Talk to your doctor or pharmacist for advice on how to help prevent constipation. If you develop severe (spasmodic) pain and swelling in the stomach, are unable to pass a bowel motion and feel sick or are being sick, talk to your doctor straight away. Patch sticking to another person The patch should be used only on the skin of the person for whom it has been prescribed. There have been reports of patches accidentally sticking to a family member while in close physical contact or sharing the same bed as the person wearing the patch. A patch accidently sticking to another person (particularly a child) can cause the medicine in the patch to go through the skin of the other person and cause serious side effects such as breathing difficulties, with slow or shallow breathing which may be : : : Transdermal patches (matrix) fatal. In case the patch sticks to the skin of another person, take the patch off right away and get medical attention. The patches should not be divided, cut into smaller parts or damaged in any way as this affects the quality and safety of such patches. Children and adolescents FENDERMAL is contraindicated in children under 12 years of age

Pregnancy and breastfeeding

• FENDERMAL should not be used during pregnancy or 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 this medicine
• • Do not use FENDERMAL during labour and delivery (including caesarean section), because FENDERMAL may cause breathing problems in the new born child
• • If you become pregnant during treatment with FENDERMAL transdermal patch, consult your doctor
• • FENDERMAL passes into the breast milk and may cause undesirable effects to your baby
• Discard any breast milk produced during treatment or within 72 hours after the removal of the last patch

Interactions and medicines to check

The approved leaflet names these interactions.

• Barbiturates (used for treating sleep disorders and epilepsy)
• Buprenorphine, nalbuphine or pentazocine (other strong painkillers)
• Some painkillers for nerve pain (gabapentin and pregabalin). It is not recommended to use the following medicines together with FENDERMAL: Medicines that affect brain function for example:
• Medicines used for treating anxiety (anxiolytics) and to help you calm down (tranquillizers)
• Medicines used for treating depression called Selective Serotonin Re-uptake Inhibitors (SSRIs) or Serotonin Noradrenaline Re-uptake Inhibitors (SNRIs) (such as citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, sertraline, venlafaxine or duloxetine)
• Medicines used for treating psychological disorders (neuroleptics)
• Anaesthetics (medicines that bring about a reversible loss of consciousness, used in surgery), if you think you are going to receive anaesthesia, tell the doctor or dentist that you are using FENDERMAL
• Medicines used for treating sleep disorders (hypnotics, sedatives)
• Medicines used for treating allergies or travel sickness (antihistamines/ anti-emetics). : : : Transdermal patches (matrix)
• Other strong-acting painkillers (opioids)
• Alcohol. You should not take the medicines listed below at the same time as using FENDERMAL, unless you are closely monitored by your doctor. These medicines may increase the effects and side effects of FENDERMAL. This applies, for example, to:
• Ritonavir (used to treat AIDS)
• Ketoconazole, itraconazole, fluconazole, voriconazole (used to treat fungal diseases)
• Diltiazem, amiodarone, verapamil (used to treat heart disease)
• Cimetidine (used to treat gastrointestinal diseases)
• Erythromycin, clarithromycin (antibiotics used to treat infections)
• Medicines for relaxing your muscles
• Medicines used for treating high blood pressure
• Medicines used for treating diarrhoea (such as loperamide, diphenoxylate, atropine), as they may cause severe constipation
• Some medicines used to treat angina (chest pain)
• Some medicines used to treat cancer of the blood (such as idelalisib). The following medicines may make FENDERMAL less effective:
• Medicines to treat tuberculosis (such as rifampicin)
• Carbamazepine, phenytoin and phenobarbital (normally used for epilepsy). Please tell your doctor if you are taking MAO – inhibitors (monoamine oxidase inhibitors) (e.g. moclobemide for depression or selegiline for Parkinson’s disease) or have taken them within the last 14 days. If these medicines are taken together with FENDERMAL this may enhance their toxicity. FENDERMAL with food, drink and alcohol You should not consume alcohol during FENDERMAL treatment. Alcohol may increase the risk of severe side effects and may cause breathing problems, a drop in blood pressure, sleepiness and coma. : : : Transdermal patches (matrix)

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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