Acute opioid withdrawal on accidental injection of naltrexone

Opioid Withdrawal Precipitated by Long-Acting Antagonists

BACKGROUND

Precipitated opioid withdrawal (POW) after opioid antagonist administration can be challenging to manage in the emergency department (ED), particularly if caused by a long-acting opioid antagonist such as naltrexone. There are no evidence-based guidelines to assist in safely and efficiently managing patients with this syndrome.

OBJECTIVE OF REVIEW

To review current practice on the treatment of long-acting antagonist POW and make recommendations on the treatment of this complex disease process.

METHODS

A literature search of opioid withdrawal cases precipitated by naltrexone was done using PubMed. One of the authors screened all the results of this search by title and abstract, leading to a final count of 27 articles that were reviewed in full by all authors. English language cases that involved precipitated opioid withdrawal from a long-acting opioid antagonist were included. Data were extracted, including the precipitant involved and dose, severity of opioid withdrawal, treatments rendered, and response to treatment. In all cases where symptoms and signs were described, a Clinical Opiate Withdrawal Scale score was calculated based on the information available.

RESULTS

Twenty-seven papers were included. Naltrexone alone was the primary antagonist reported in 19 of the papers, extended-release naltrexone in two, naltrexone-morphine combination in two, and nalmefene in four. Treatment most commonly included fluid replacement, benzodiazepines, antiemetics, and clonidine. Full opioid agonist treatment, although often suggested, was poorly described. Buprenorphine successfully reduced the severity and duration of withdrawal in several cases. No standardized response scale was used, and response to treatment ranged from 3 to 48 h prior to resolution of clinical effects.

CONCLUSIONS

Management of POW from long-acting antagonists is a complex problem with little formal evaluation of treatment options. There is not currently a sufficiently robust body of literature to support an evidence-based guideline. However, use of intravenous fluids, antiemetics, and benzodiazepines is commonly reported as successful and seems to be a reasonable approach until this process is better studied. A treatment strategy using partial agonists such as buprenorphine is emerging and may represent a safe and effective treatment pathway for these patients.

Perspectives on Cancer Pain Assessment and Management in Children

OBJECTIVE

To report evidence regarding pain assessment and management for children and adolescents receiving treatment for cancer.

DATA SOURCES

Published research and clinical guidelines.

CONCLUSION

Children and adolescents experience multiple sources of pain across the cancer continuum. They require developmentally relevant approaches when assessing and managing pain. This review suggests that consideration of the developmental stage and age of the child are essential in both pain assessment and pain management.

IMPLICATIONS FOR NURSING PRACTICE

Pediatric oncology nurses play a key role in developmentally appropriate pain assessment, identification of potential strategies to manage pain, and delivery of pharmacologic and nonpharmacologic therapies.

Naltrexone metabolism and concomitant drug concentrations in chronic pain patients

Naltrexone is effective in treating opioid dependence by blocking µ, κ and δ opiate receptors. Naltrexone is mainly metabolized to an active metabolite 6β-naltrexol by dihydrodiol dehydrogenase enzymes. Concomitant opioids will not be effective while patients are taking this antagonist. This was a retrospective analysis of urinary excretion data collected from patients being treated with pain between November 2011 and May 2012. Naltrexone, 6β-naltrexol and concomitant opiate concentrations were measured by liquid chromatography-tandem mass spectrometry. Interpatient variability was calculated from first-visit specimens, and intrapatient variability was calculated from patients with two or more visits. Relationships of the metabolic ratio (MR; 6β-naltrexol/naltrexone) with age, gender and urinary pH were also explored. From 88 first-visit patient specimens, the median MR was 3.28 (range 0.73-17.42). The MR was higher in women than men (5.00 vs. 3.14, P< 0.05). The MR showed no association based on age and urinary pH. Eighteen of 88 patients taking oral naltrexone tested positive for concomitant opiate use. Urinary MRs of 6β-naltrexol/naltrexone were highly variable, which may contribute to variability in efficacy, toxicity and patient willingness to take naltrexone as directed. Twenty percent of patients tested positive for opiates and naltrexone, thus showing the importance of monitoring patients taking naltrexone.

Withdrawal syndrome caused by naltrexone in opioid abusers

STUDY OBJECTIVE

Naltrexone is a competitive opioid receptor antagonist acting at the µ- and k-opioid receptors that blocks the euphoric effects of exogenous administered opioids. When used in opioid-dependent patients, naltrexone can cause acute and severe withdrawal symptoms.

METHODS

This was a cross-sectional study conducted from December 2007 to March 2008 and consisted of patients who had used naltrexone accidentally or deliberately and were referred to Loghman-Hakim Poison Hospital, Tehran, Iran. All symptoms and signs were assessed and the relationship between the dose of naltrexone, opioid dependence, and outcome was evaluated.

RESULTS

In 132 patients referred to our hospital, the most frequently reported symptoms and signs occurring in more than 10% of patients were agitation (96.2%), altered level of consciousness (38.6%), nausea (28%), vomiting (27.3%), abdominal pain (24.2%), diarrhea (16.7%), bone and muscle pain (15.9%), tachycardia (12.9%), and dilated pupils (11.4%). Being the most prominent symptom, the agitation was the most difficult aspect of withdrawal to manage. Except for agitation, no relationship was found between the presence of these symptoms and the dose of naltrexone used. Outcome of the patients (classified as complete recovery, partial recovery, death, and no follow-up) was related to the substance of addiction (p < 0.05) but not to the naltrexone dose.

CONCLUSION

Emergency physicians should be aware of the potential for severe agitation from naltrexone-precipitated hyperacute withdrawal and its appropriate management. Opioid-dependent patients who wish to continue withdrawal and abstinence must be encouraged to visit trained physicians and be warned about misuse of naltrexone.

Antagonist treatment of opioid withdrawal translational low dose approach

Although antagonist drugs are receiving increasing attention in the treatment of opioid withdrawal, the mechanisms of interaction of opiate agonists and antagonists remain largely to be investigated. We focused on the effects of very low quantities of opiate antagonists, following the clinical indication of their potential utility in detoxification. Upon reviewing the evidence on the administration of small doses of naloxone and naltrexone in the presence of agonist drugs, the effects of low-dose naltrexone during opiate administration and withdrawal are described. The application of a translational methodology allowed completing the clinical design with behavioral and cellular information obtained from a specifically developed animal model. The initial results indicate that low doses of naltrexone may help reducing the manifestation of opioid withdrawal, offer suggestions for further investigations and confirm the utility of a translational research approach to the clinical neurobiology of drug addiction.

Effect of oral naltrexone on pruritus in cholestatic patients

AIM: To determine the efficacy and potential complications of oral naltrexone used in the treatment of pruritus in cholestatic patients and to compare them with other studies.

METHODS: Thirty-four enrolled cholestatic patients complaining of pruritus were studied. In the initial phase, pruritus scores during day and night were e v a l u a t e d . Subsequently, patients were given a placebo for one week followed by naltrexone for one week. In each therapeutic course (placebo or naltrexone) day and night pruritus scores were distinguished by a visual analogue scale (VAS) system and recorded in patients’ questionnaires.

RESULTS: Both naltrexone and placebo decreased VAS scores significantly. Naltrexone was more effective than placebo in decreasing VAS scores. Both day and night scores of pruritus decreased by half of the value prior to therapy in thirteen patients (38%). Daytime pruritus improved completely in two patients (5.9%), but no improvement in the nighttime values was observed in any patient.

Sixteen patients (47%) suffered from naltrexone complications, eleven (32%) of them were related to its withdrawal. Complications were often mild. In the case of withdrawal, the complication was transient (within the first 24-28 h of therapy) and self-limited. We had to cease the drug in two cases (5.9%) because of severe withdrawal symptoms.

CONCLUSION: Naltrexone can be used in the treatment of pruritus in cholestatic patients and is a safe drug showing few, mild and self-limited complications.