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- Specific opioid antagonist
- Respiratory depression induced by opioids (analgesia, anaesthesia, intoxication)
Forms and strengths, route of administration
- 0.4 mg in 1 ml ampoule (0.4 mg/ml) for IV, IM injection or infusion in sodium chloride 0.9% or glucose 5%
IV route is preferred, use IM route if IV route is not feasible:
- Child: 5 to 10 micrograms/kg by IV injection, repeated if necessary after 2 to 3 minutes, until adequate spontaneous ventilation is restored, followed by a continuous infusion of 1 to 5 micrograms/kg/hour, or by 5 to 10 micrograms/kg by IM injection every 90 minutes
- Adult: 1 to 3 micrograms/kg by IV injection, repeated if necessary after 2 to 3 minutes, until adequate spontaneous ventilation is restored, followed by a continuous infusion of 1 to 5 micrograms/kg/hour, or by 5 to 10 micrograms/kg by IM injection every 90 minutes
- The duration of action of naloxone (20 to 30 minutes by IV route) is shorter than that of opioids: administration must be maintained several hours even if breathing improves.
Contra-indications, adverse effects, precautions
- May cause:
- tachycardia, fibrillation, hypertension, pulmonary oedema when given postoperatively, due to a sudden reversal of analgesia;
- nausea, vomiting;
- acute withdrawal syndrome in opioid-dependent patients.
- Administer with caution and reduce dosage in case of heart failure or coronary artery disease.
- Naloxone is used in addition to assisted ventilation and must be administered under close medical supervision.
- Pregnancy: risks linked to respiratory depression appear greater than risks linked to naloxone.
- Breast-feeding: no contra-indication
- Naloxone is a specific opioid antidote. It cannot be used to antagonise the effects of other drugs producing CNS or respiratory depression.
- Efficacy in antagonising opioid effects depends not only on the dose of naloxone but also on the dose and potency of the specific opioid involved.
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