Naloxone: intravenously, intramuscular, inhalatory and intranasal use in emergency cases

The use of naloxone in emergency medicine is primarily connected to the treatment of a syndrome known as overdose, which is cause by non-essential use of heroin and certain opioid agonists. The dose of naloxone required to be efficacious depends on the quantity of opioid assumed, its receptorial affinity and its kinetics: in propoxyphene and pentazocine intoxication, for instance, higher doses are require than those needed in the treatment of morphine or heroin overdose. Intravenous administration is the most efficacious and fast-acting method: however, in certain cases, and depending on aspects that are typical of overdose patient management (e.g. the difficulties connected to vein access, skin scarring, severe hypotension), alternative pathways may be used. These include intraand sub-lingual and intratracheale administration, inhalatory administration via nebulisation (possible in the presence of respiratory action only), and intramuscular and subcutaneaous administration (which are efficacious in the absence of hypoperfusion). However, the most promising means of administration would appear to be intranasal administration, thanks to the relative ease of access, lower risk of contact with bodily fluids and the excellent bioavailability and rapidity of the effect, which is similar to that achieved with intravenous administration.