Naloxone

How it works

It competitively displaces opioids from mu-opioid receptors, rapidly reversing their central depressant effects, but has a short duration of action.

Prescribing in practice

• Its effect can wear off before that of long-acting opioids, so patients must be observed and may need repeated doses or an infusion to prevent re-narcotisation.
• In opioid-dependent patients it can precipitate acute withdrawal with agitation, pain and cardiovascular effects, so titrate carefully where the aim is to restore adequate breathing.
• Always call for emergency help and provide supportive airway and ventilatory care alongside administration.

Monitoring

Monitor conscious level, respiratory rate and oxygen saturation continuously, watching for recurrence of opioid effect as naloxone wears off.

Counselling the patient

• After giving naloxone, always seek emergency medical help because the opioid effect can return.
• Lay rescuers should be shown how to recognise overdose and administer the kit.
• Stay with the person and be prepared to give a further dose if breathing deteriorates again.

Evidence & guidelines

Naloxone is the established antidote for opioid overdose, and take-home naloxone programmes are supported by UK public health guidance.