There is limited clinical experience with naloxone hydrochloride injection overdosage in humans.
In one small study, volunteers who received 24 mg/70 kg did not demonstrate toxicity.
In another study, 36 patients with acute stroke received a loading dose of 4 mg/kg (10 mg/m2/min) of naloxone hydrochloride injection followed immediately by 2 mg/kg/hr for 24 hours. Twenty-three patients experienced adverse events associated with naloxone use, and naloxone was discontinued in seven patients because of adverse effects. The most serious adverse events were: seizures (2 patients), severe hypertension (1), and hypotension and/or bradycardia (3).
At doses of 2 mg/kg in normal subjects, cognitive impairment and behavioral symptoms, including irritability, anxiety, tension, suspiciousness, sadness, difficulty concentrating, and lack of appetite have been reported.
In addition, somatic symptoms, including dizziness, heaviness, sweating, nausea, and stomachaches were also reported. Although complete information is not available, behavioral symptoms were reported to often persist for 2 to 3 days.
Up to 11 doses of 0.2 mg naloxone (2.2 mg) have been administered to children following overdose of diphenoxylate hydrochloride with atropine sulfate. Pediatric reports include a 2½ year-old child who inadvertently received a dose of 20 mg naloxone for treatment of respiratory depression following overdose with diphenoxylate hydrochloride with atropine sulfate. The child responded well and recovered without adverse sequelae. There is also a report of a 4½ year-old child who received 11 doses during a 12-hour period, with no adverse sequelae.
Patients who experience a naloxone overdose should be treated symptomatically in a closely supervised environment. Physicians should contact a poison control center for the most up-to-date patient management information.