naloxone (Narcan)

Introduction

naloxone is an opiate antagonist used to reverse the respiratory depressant effects of opiates and opioids such as heroin
it has a short half life of 60-90 minutes which is much shorter than most opiates and thus there is a risk of rebound respiratory depression once it has worn off, and risk of death
administering too high a dose, too quickly can result in acute opiate withdrawal syndrome
the usual preferred aim is to titrate the dose to gain return of adequate spontaneous breathing and airway protection whilst maintaining a level of sedation to avoid premature self-discharge
overdose of long acting opiates such as methadone requires prolonged infusion of naloxone - see methadone overdose

All patients given naloxone should be observed for re-sedation for at least 2 hours (preferably 4-6hrs, and in children, 24hrs) after the last dose and given warning of chance of rebound toxicity

100 micrograms IV or 400 micrograms I/Nasal, IM or SC (children: 10 microgram/kg to a maximum of 400 micrograms)
- rpt as needed every 30-60secs or so, until spontaneously breathing

100 microgram/hour can be made up of a 2 mg naloxone vial diluted in 100 ml of 0.9% saline and running at 5 ml/hour
start hourly infusion at 2/3rd of the total initial doses of naloxone required in the first 1 hour
in addition, one-half of the initial hour bolus dose should be administered (as a bolus) 15-20 min. after the start of the infusion to prevent a drop in naloxone levels
best way to titrate the naloxone is patient breathing (resp. rate > 12/min) but still sedated to reduce probability of premature absconding patient who will then have a high chance of delayed onset death