Fentanyl

How it works

It is a strong agonist at mu-opioid receptors, producing rapid, short-lasting analgesia and sedation; its high lipophilicity gives fast onset and a short duration after a single dose.

Prescribing in practice

• It is a high-potency opioid that can cause rapid respiratory depression and apnoea, so it must only be used where airway support, oxygen, monitoring and naloxone are immediately available.
• Rapid intravenous administration of higher doses can precipitate chest-wall and glottic rigidity, impairing ventilation.
• Effects are markedly potentiated by other CNS depressants and benzodiazepines, increasing the risk of profound sedation and respiratory compromise.

Monitoring

Monitor respiratory rate, oxygen saturation, sedation level and blood pressure continuously during and after administration.

Counselling the patient

• This is a strong, fast-acting painkiller that can slow your breathing, so you will be closely watched.
• Tell staff at once if you feel very drowsy or short of breath.
• Avoid alcohol and other sedating medicines around the time it is given.

Evidence & guidelines

Fentanyl is an established opioid for acute severe pain and procedural use in emergency and anaesthetic practice.