Naloxone

How it works

Naloxone competitively displaces opioids from mu (and other) opioid receptors, rapidly reversing opioid effects including respiratory depression and sedation.

Prescribing in practice

• Its duration of action is often shorter than that of the opioid being reversed, so repeated doses or an infusion and continued observation are essential to prevent re-sedation.
• In opioid-dependent patients reversal can precipitate an acute withdrawal syndrome, so titrate to restore adequate breathing rather than full consciousness.
• It is ineffective against respiratory depression caused by non-opioid agents and gives no benefit where opioids are not involved.

Monitoring

Monitor respiratory rate, conscious level and oxygen saturation closely and for a prolonged period after administration because of the risk of recurrent respiratory depression.

Counselling the patient

• Anyone given naloxone for an overdose must be kept under observation, as the opioid effect can return as the antidote wears off.
• Family and carers should know how to recognise overdose and call emergency services even after naloxone is given.

Evidence & guidelines

Naloxone is the recognised standard antidote for opioid toxicity in resuscitation and toxicology guidance, including take-home naloxone programmes for overdose prevention.