We read with great interest the article by Galvin and colleagues, describing the incidence and outcomes of patients admitted to their intensive care unit with seizures, coma or cardiac arrest associated with cocaine use [1]. They identified an exponential increase in admissions over their study period mirroring evidence of greater supply of cocaine by dealers, a situation that has also occurred in the UK. Here there has been a 500% increase in cocaine use since 1996, with 3% of those aged 16 to 59 estimated to consume the drug [2].

We were also struck by the high mortality rate reported, contrasting reports from other countries, and would agree that this may be the result of employment of more lethal cutting agents. Cutting agents are substances with a similar physical appearance to cocaine mixed with it, decreasing purity and increasing profits - ranging from pharmacologically inactive substances such as talcum powder to local anaesthetic agents. Recently we reported a case of convulsions in a patient known to have consumed cocaine [3]. Of relevance was that the seizures were preceded by blue discolouration of his skin and mucus membranes, later determined to be methaemoglobinaemia attributable to adulteration of the cocaine with benzocaine. Benzocaine has been used widely in healthcare in the USA where its relationship with methaemoglobinaemia is well described as are the risks it poses as a cutting agent for cocaine [4-5].

It would appear that benzocaine has well and truly arrived on the UK’s shores and it is being adopted increasingly as one of the principal adulterating agents for cocaine [6]. Use of benzocaine as a cutting agent now features on a UK drug information website although the hazard of methaemoglobinaemia is not specifically mentioned [7]. Benzocaine and other local anaesthetic agents are used as they mimic the ‘freeze’ or nasal numbness associated with cocaine use, fooling users into thinking they have a more potent product. However as cocaine purity drops, users are at greater risk of toxicity from the rising concentrations of adulterants.

As frequent providers of critical care in emergency departments, anaesthetists and intensivists need to be aware of these newer side effects of cocaine abuse and this dangerous drug mixture.

No external funding and no conflicts of interest declared

A. Chakladar

J. W. Willers

D. R. Uncles

E-mail: abhijoy.chakladar@gmail.com

Brighton and Sussex University Hospitals NHS Trust

Brighton, UK

Western Sussex Hospitals NHS Trust

Worthing, UK

References

1. Galvin S, Campbell M, March B, O’Brien B. Cocaine-related admission to an intensive care unit: a five-year study of incidence and outcomes. Anaesthesia 2010; 65: 163-6.

2. Hoare J. Drug Misuse Declared: Findings from the 2008/09 British Crime Survey.  Home Office Statistical Bulletin 12/09. London, Home Office (UK), 2008.  http://www.homeoffice.gov.uk/rds/pdfs09/hosb1209.pdf (accessed 20/02/2010).

3. Chakladar A, Willers JW, Pereskokova E, Beaumont PO, Uncles DR. White powder, blue patient: Methaemoglobinaemia associated with benzocaine-adulterated cocaine. Resuscitation 2009; 81: 138-9.

4. Weinberg GL. Banning Benzocaine: Of Bananas, Bureaucrats, and Blue Men. Anesthesia & Analgesia 2009; 108: 699-701.

5. McKinney CD, Postiglione KF, Herold DA. Benzocaine-Adultered Street Cocaine in Association with Methemoglobinemia. Clinical Chemistry 1992; 38(4): 596-597.

6. BBC News online. Full list of impurities found in cocaine. http://news.bbc.co.uk/1/hi/uk/8040690.stm (accessed 16/02/2010).

7. Ask Frank. Cocaine impurities. http://www.talktofrank.com/basement.aspx (accessed 20/02/2010).

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