Effect of innappropriate naltrexone use in a heroin misuser

Abstract

Naltrexone is a long acting opioid receptor antagonist used in controlled opioid withdrawal drug programmes. When taken by an opioid dependent patient an acute withdrawal reaction will be precipitated. The case is presented where a known opioid drug misuser inadvertently ingested naltrexone in conjunction with heroin resulting in severe agitation, requiring heavy sedation followed by general anaesthesia to enable investigation and management of his clinical condition. N altrexone is a long acting opioid receptor antagonist used in drug rehabilitation programmes to maintain opioid abstinence. However, when consumed in conjunction with an opioid substance, prolonged opioid withdrawal will be precipitated resulting in unpredictable and life threatening medical consequences. We present a case where a known drug misuser consumed naltrexone in conjunction with heroin. CASE REPORTA 39 year old man presented to the accident and emergency department having taken up to three, 50 mg tablets of naltrexone and having smoked an unknown quantity of heroin. He was known to be an injecting drug user and to suffer from epilepsy. No other recreational drugs, alcohol, or prescribed medications were known to have been consumed. On arrival he was extremely agitated being restrained by four police officers. He was confused, sweating, with episodes of profuse projectile diarrhoea and vomiting. Glasgow Coma Scale was 12 (spontaneous eye opening, localising to pain, and using inappropriate speech). Pupils were dilated but reactive to light. Heart rate was regular at 180 beats/minute and respiratory rate 40 breaths/minute. Blood pressure, oxygen saturation, blood glucose, and temperature were normal. There was no evidence of head injury and no history of seizure. Urea, electrolytes, full blood count, and arterial blood gas measurements were normal. Initial attempts at sedation using a combination of titrated intravenous midazolam and droperidol were unsuccessful. After receiving a total of 20 mg midazolam and 15 mg droperidol he continued to be confused, agitated, and increasingly violent. An urgent CT head scan was arranged to exclude any intracranial pathology. To expedite this he was anaesthetised and ventilated. Rapid sequence induction of anaesthesia was carried out using 200 mg propofol, and 100 mg suxamethonium. Anaesthesia was maintained with a propofol infusion and incremental paralysis with atracurium.CT of his brain was normal. A lumbar puncture was performed while the patient was still anaesthetised. This showed no abnormality. The patient was extubated four hours after induction and transferred to the medical high dependency unit for observation. Further episodes of agitation occurred overnight requiring additional sedation with intravenous midazolam. The following morning he took his own discharge. Retrospectively urine toxicology screen confirmed the presence of cannabinoids, benzodiazepines, and opioids.

Nalmefene Mistakenly Prescribed to Reduce Alcohol Consumption in Patients Under Buprenorphine Substitution Therapy Resulting in Acute Opioid Withdrawal

“…7 Accidental or intentional ingestion of an opioid antagonist in opioid-dependent patients will result in an acute OW reaction, as described with naltrexone in heroin users. 1,2,[8][9][10] The EPs asked for the specialized mobile addiction team to help in patient management. The questions raised by the EPs were: how long should the patient be observed?…”

“…Titrated doses of opioids could aid in improving the withdrawal symptoms but is still debated. Some authors consider that methadone, BUP, and opioid agents are not appropriate in this emergency context, 2,8 whereas others in a case of severe OW precipitated by nalmefene administered titrated doses of a short-acting opioid. 12 It is important to underline the differences between our patients and those studied by Donnerstag et al, 12 who were dependent on codeine or methadone.…”

“…7 In animal models, nalmefene resulted in being more effective than naltrexone, another opioid modulator shown to be effective in BED. 8 However, naltrexone, despite showing a similar affinity for MOR, behaves as an antagonist of MOR, DOR, and KOR. 9 Available evidence suggests that such mechanisms may be involved also in food craving.…”

The frequency of agitation due to inappropriate use of naltrexone in addicts

“…Symptoms include agitation, confusion, hallucinations, sweating, hyperthermia, tachycardia, abdominal pain, vomiting, diarrhea, increased creatine kinase (CPK), and rhabdomyolysis. [ 6 ]…”

“…However, one of the acute symptoms of drug withdrawal syndrome following the use of naltrexone is restlessness or agitation, which has no effective treatment so far, and sometimes requires general anesthesia in severe cases. [ 5 6 7 ]…”