(1989; 60 pages) [French]
Group: opioid antagonist
Injection: 0.4 mg (hydrochloride) in 1-ml ampoule
Naloxone is a semisynthetic opioid antagonist that competes with opioid analgesics for specific receptor sites in the central nervous system. Its effect, which persists for about 45 minutes, occurs within 1-2 minutes of intravenous administration.
To counteract respiratory depression induced by opioids administered during anaesthesia or by opioid overdosage.
Dosage and administration
Adults: 100-400 micrograms i.v. titrated to the needs of the patient and repeated, as necessary, at intervals of 2-3 minutes.
Children: 5-10 micrograms/kg i.v. repeated as above.
Neonates: 10 micrograms/kg i.v., i.m. or subcutaneously immediately after birth.
Adults: 200 micrograms i.v. repeated, as necessary, at 2-minute intervals to a maximum of 10 mg.
Dosage should be reduced in patients with cardiovascular conditions predisposing to dysrhythmias.
• Known hypersensitivity to naloxone.
• Physical dependence on narcotics (naloxone will precipitate an acute withdrawal syndrome in dependent patients).
The use of naloxone to counteract respiratory depression complements other resuscitative measures including maintenance of a clear airway, control of ventilation, cardiac massage, maintenance of an effective circulatory volume and vasopressor therapy. The necessary facilities and equipment for such treatment must be immediately available.
Use in pregnancy
Naloxone should be used during pre-term pregnancy only when the need outweighs any possible risk to the fetus.
Unnecessarily high doses may cause hypertension and tachycardia. Transient nausea, vomiting, sweating, tachycardia, hypertension and tremor have been reported. Seizures are rare.
Patients with pre-existing cardiovascular disease have occasionally developed ventricular dysrhythmias.
Excessive dosage results in convulsions, raised blood pressure and loss of preexisting opioid analgesia.
Naloxone injection should be kept protected from light.