Benzocaine-Adultered Street Cocaine in Association with Methemoglobinemia

Abstract

A 27-year-old man with a history of cocaine abuse ingested a large quantity of street cocaine in an apparent suicide attempt. Shortly thereafter, he developed tonic-clonic seizures and became cyanotic. An arterial blood gas sample, collected in the emergency department, appeared chocolate-brown and showed pO2 279 mmHg, pCO2 53 mmHg, and pH 7.15. Hemoglobin spectral analysis revealed significant methemoglobinemia (37%). Subsequent gas-chromatographic and mass-spectral analysis of urine confirmed the presence of cocaine (106 mg/L), benzoylecgonine (94 mg/L), and other metabolites. Further testing revealed the presence of benzocaine, a compound known to produce methemoglobinemia. A powder submitted as the "cutting" substance was shown to be benzocaine. When confronted with a possible cocaine overdose (particularly by ingestion), the physician should consider the possible clinical effects of adulterants, especially local anesthetics such as benzocaine.

A chemical analysis examining the pharmacology of novel psychoactive substances freely available over the internet and their impact on public (ill)health. Legal highs or illegal highs?

“… 21 The presence of benzocaine in legal highs is well documented. 5 22 However, it is never listed as one of the active ingredients meaning each product contains indefinite quantities, which is disturbing since research estimates that benzocaine induced methemoglobinaemia only requires a small amount to cause cyanosis 19 23 (a bluish discolouration of the skin caused by a deficiency of oxygen in the blood). Although there have been no known deaths from benzocaine, the death of a teenager was attributed to cocaine containing four times the toxic dose of lidocaine, 24 illustrating the potential health risks arising from the varied composition of these products.…”

Methaemoglobinaemia associated with the use of cocaine and volatile nitrites as recreational drugs: a review

“…The first case of cocaine-related methaemoglobinaemia reported in the medical literature was in 1992 [25]. A 27-year-old man presented to an emergency department with tonic-clonic seizures and severe cyanosis following use of a large quantity of street cocaine.…”

“…Cocaine itself and its metabolites are not recognized to cause methaemoglobinaemia. However, there are reports, discussed below in more detail, of adulterants added to cocaine that are associated with methaemoglobinaemia [25–28]. An adulterant is a pharmacologically active substance added to a recreational drug.…”

“…Classical ‘toxidromes’ associated with various classes of recreational drugs are recognized, but frequently patients will present with symptoms and signs that do not correlate with the direct action of the drug allegedly ingested. One example of this is methaemoglobinaemia, which has been recognized as a consequence of recreational use of volatile nitrites since the late 1970s [1–24], and more recently there have been case reports of methaemoglobinaemia in individuals recreationally using cocaine [25–28]. Unlike the case with nitrites, where the methaemoglobinaemia is directly because of the oxidizing effect of the nitrites, with cocaine, methaemoglobinaemia is because of the adulterants, rather than the cocaine itself.…”

Adulterants in crack cocaine in Brazil

“…It has previously been hypothesized that there is a synergistic relationship, or cross-sensitization, between cocaine and levamisole, and cocaine alone has been linked to necrotizing granulomatous vasculitis and Churg-Strauss vasculitis 30. Another severe complication of chronic cocaine abuse, related to adulteration of cocaine with phenacetin and local anesthetics, is methemoglobinemia,31,32 which can lead to severe hypoxemia, seizures, coma,and death. This blood disorder is characterized by the presence of circulating methemoglobin in erythrocytes, resulting in reduced tissue oxygen due to a reduction of the oxygen-carrying ability of erythrocytes, and an increased affinity for oxygen in non-affected heme molecules, which impairs the off-loading of oxygen to the tissues.…”