Mental Health  |  OST Drug Issues Pathway - Buprenorphine/Naloxone Toxicity

Mental Health

OST Drug Issues Pathway - Buprenorphine/Naloxone Toxicity

Buprenorphine is a partial opiate agonist and unlike full agonists (morphine, methadone), the pharmacological effects of buprenorphine exhibit a "ceiling effect" with increasing doses. This makes buprenorphine/naloxone safer in overdose than, say, methadone, as the negative opiate effects (eg respiratory depression) are also constrained by this ceiling effect. Nevertheless, certain groups may be particularly vulnerable to respiratory depression, eg children, those who are opiate-naïve or individuals with chronic obstructive pulmonary disease, and care should be taken to consider these factors when prescribing.

Although buprenorphine is far safer than full opiate agonists in overdose, there have been some reports of fatalities in adult users, and in particular where there have been contributing factors including:

  • Opiate-naïve users.

  • Co-use of other substances (alcohol, benzodiazepines).

  • Use by crushing and snorting (although this risk is reduced with buprenorphine/naloxone due to the presence of naloxone).

Children who accidentally ingest buprenorphine/naloxone are particularly at risk of toxic effects:

  • Toxic effects are more pronounced in children under 2 years of age.

  • In retrospective studies, effects below 2mg dose were unlikely to be severe but at least some effects (lethargy, nausea, vomiting) occurred in all children who ingested 4mg or more.

  • Respiratory depression occurred in 7% of paediatric overdoses, and coma in 3%.

Immediate hospital treatment must be sought in every case where a child or a non-tolerant adult has ingested buprenorphine/naloxone. Similarly, those who are prescribed buprenorphine/naloxonemust be medically assessed if overdose or co-use of other respiratory depressants (alcohol, benzodiazepines) is suspected.


Last updated : Thursday, January 09, 2020
Next review date : Friday, January 08,2021

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