Fentyl

Indications

Fentanyl is a very strong opioid pain reliever. As an injection it is used in hospital for pain relief during and after surgery, as part of anaesthesia, and in intensive care. As skin patches it is used for severe, long lasting pain, such as cancer pain, in people who already take regular opioid medicines and are tolerant to them. It is not for mild pain or short term pain.

How It Works

Fentanyl attaches to opioid receptors in the brain and spinal cord. This blocks pain signals and changes how the brain feels pain. It is about 50 to 100 times stronger than Morphine, so very small doses are used.

Dosage and Administration

Injections are given only by a doctor, anaesthetist or nurse, with the dose set for each patient and breathing closely monitored. Patches are used exactly as prescribed: apply to clean, dry, hairless, unbroken skin on the upper arm, chest or back, press firmly for 30 seconds, and usually change every 72 hours, using a new site each time. Do not cut patches, and keep heat sources (heating pads, hot baths, saunas) away from the patch, as heat increases absorption. Fold used patches sticky side together and dispose of them safely.

Interactions

• Alcohol, benzodiazepines, sleeping tablets, other opioids, Gabapentin, Pregabalin and sedating antihistamines can cause dangerous slowing of breathing.
• Clarithromycin, Ketoconazole, Itraconazole, Ritonavir, Fluconazole and grapefruit juice raise fentanyl levels and the risk of overdose.
• Rifampicin and Carbamazepine reduce its effect; stopping them can raise levels.
• With serotonergic antidepressants (SSRIs, SNRIs) or MAO inhibitors, a serious reaction called serotonin syndrome can occur.

Contraindications

• Allergy to Fentanyl or the patch adhesive.
• Severe breathing problems or severe asthma without monitoring.
• Patches in people not already tolerant to opioids, and for short term or post operative pain.
• Bowel blockage.

Side Effects

Common effects include drowsiness, nausea, vomiting, constipation, dizziness, sweating, itching, dry mouth and confusion. Patches can cause skin redness. Long term use can lead to tolerance and dependence.

Get urgent medical help if breathing becomes slow, shallow or noisy, the person is very sleepy, cannot be woken, has pinpoint pupils, blue lips, or collapses. Also seek help for chest tightness, fits, severe confusion, or agitation with fever and muscle twitching.

Pregnancy and Lactation

It should be used in pregnancy only if clearly needed. Long term use can cause withdrawal in the newborn, and use during labour can slow the baby's breathing. It passes into breast milk; breastfeeding is not recommended during regular use, and the doctor will advise.

Precautions and Warnings

• Controlled medicine: there is a risk of addiction, misuse and overdose; keep it locked away and never share it.
• Accidental exposure to a patch can be fatal for children; check that patches have not fallen off and stuck to someone else.
• Do not drive or use machines if drowsy.
• Do not stop suddenly after long use; the dose should be reduced slowly.
• Fever can increase absorption from patches; tell your doctor.

Overdose

Overdose causes extreme sleepiness, slow or stopped breathing, pinpoint pupils and unconsciousness, and can be fatal. Remove any patch, call emergency services at once, and give Naloxone if available.

Therapeutic Class

Opioid analgesic (controlled medicine).

Storage

Store below 25°C in the original pack, away from light and heat, locked away and out of the reach and sight of children. Hospital injections are stored as directed on the pack.