Naloxone (Intravenous — Opioid Reversal)

Source: eMC SPC for Naloxone 400 micrograms/ml solution for injection — an injectable product, matching this page's IV/critical-care context. Dosage is determined for each patient to obtain optimum respiratory response while maintaining adequate analgesia. INFUSION (exact wording, no numeric rate is stated in the SPC): 'The duration of action for some opioids is longer than that of the naloxone hydrochloride i.v. bolus. Therefore, in situations where depression is known to be induced by such substances or there is a reason to suspect this, naloxone hydrochloride should be administered as a continuous infusion. The infusion rate is determined according to the individual patient, depending on the response of the patient to the i.v. bolus and on the reaction of the patient to the i.v. infusion. The use of the continuous intravenous infusion should be carefully considered and respiratory assistance should be applied if necessary.' No mg/kg/h or micrograms/kg/min infusion rate is given in the fetched SPC — the clinician must source the infusion rate separately. Duration of action is dose- and route-dependent, varying between 45 minutes and 4 hours; because some opioids (e.g. dextropropoxyphene, dihydrocodeine, methadone) act longer than naloxone, patients must be kept under continuous supervision and repeated doses given if necessary. Elderly: use with caution in elderly patients with pre-existing cardiovascular disease or those receiving potentially cardiotoxic drugs, since serious adverse cardiovascular effects such as ventricular tachycardia and fibrillation have occurred in postoperative patients. Caution (SPC 4.4): give with caution to patients who have received high doses of opioids or are physically dependent on opioids — too rapid reversal can cause an acute withdrawal syndrome with hypertension, cardiac arrhythmias, pulmonary oedema and cardiac arrest, and this also applies to newborn infants of such patients. Reversal of buprenorphine-induced respiratory depression may be incomplete; if the response is incomplete, respiration should be mechanically assisted. Naloxone is not effective in central depression caused by agents other than opioids. After surgical opioid use, excessive naloxone dosage should be avoided as it may cause excitement, raised blood pressure and clinically important reversal of analgesia. Neonates whose mothers received opioids (SPC 4.2, weight-based — see paedDose). The openFDA provider returned no label for this id.

Verbatim source basis (eMC SPC 4.2): children, overdose — 'The usual starting dose is 0.01 mg naloxone hydrochloride per kg i.v. If the satisfactory clinical response is not achieved, the dose can be increased in the next injection to 0.1 mg/kg injection. Depending on the individual patient, an i.v. infusion may also be necessary.' Children, reversal of opioid-induced depression — 'Initially, 0.01-0.02 mg naloxone hydrochloride per kg i.v. at intervals of 2-3 minutes until satisfactory respiration and consciousness are obtained.' Neonates whose mothers have received opioids — 'The usual dosage is 0.01 mg naloxone hydrochloride per kg i.v. If the respiratory function is not reversed to a satisfactory level with this dosage, the injection can be repeated at 2 to 3 minute intervals. If i.v. administration is not possible, Naloxone 400 micrograms/ml can also be injected i.m. (initial dose 0.01 mg/kg).' Caution: naloxone can precipitate acute withdrawal in newborn infants of opioid-dependent mothers (SPC 4.4). Doses are expressed as mg of naloxone hydrochloride per kg; the product is a 400 micrograms/ml solution. Verify against a children's formulary before prescribing.