Analysis of cocaine adulterants in human brain in cases of drug-related death

For different reasons, street cocaine is often diluted with pharmacologically active substances, the so-called adulterants such as levamisole or hydroxyzine. A controversial debate exists currently on the uptake of adulterants from cocaine preparations and drug-related death. Previous research convincingly argues that serious adverse side effects that affect the central nervous and cardiovascular systems can be a consequence of adulterated cocaine.

AIMS

Having identified the presence of adulterants in lung tissue and blood, the concentrations of these substances in brain, an important target location, was of interest. This provides an opportunity to assess their role in cases of drug-related deaths.

MATERIALS AND METHODS

We developed and validated a method for the analysis of cocaine, two cocaine metabolites and six adulterants, which can typically be found in cocaine preparations, and one adulterant metabolite in brain tissue by gas chromatography-mass spectrometry (GC-MS)¹. Ten brain samples which were tested positive for cocaine were analyzed. The homogenized brain tissue was embedded into drying paper for protein precipitation. During a subsequent solid-phase extraction (SPE), the eluate and one of the wash fractions were collected. After derivatization with N-Methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) in pyridine and isooctane, the extracts were analyzed by GC-MS.

RESULTS AND DISCUSSION

The method was fully validated for cocaine (COC), benzoylecgonine (BZE), ecgonine methyl ester (EME), diltiazem (DIL), hydroxyzine (HYD), and levamisole (LEV) and partly validated for cetirizine (CET), lidocaine (LID), phenacetin (PHE), and procaine (PRO) in brain material. By analyzing post-mortem brain tissue of ten cocaine users, LEV, LID, and HYD as well as PHE were identified in contrast to DIL, PRO, and the HYD metabolite CET. HYD and LEV were found in moderate to high concentrations in some cases. Therefore, it cannot be excluded that they have caused adverse side effects.

CONCLUSION

Because adulterants can potentially affect the central nervous and cardiac systems, it is likely that they enhance COC toxicity.

A safety assessment of fixed combinations of acetaminophen and acetylsalicylic acid, coformulated with caffeine

Overuse and abuse of phenacetin-containing mixed analgesics has contributed to end-stage renal disease. Combination analgesics, especially those coformulated with caffeine, have been implicated as imparting a greater risk of analgesic-associated nephropathy (AAN) than single or coformulated analgesics without caffeine. This has led to a recommendation that the sale of "two plus caffeine" analgesic mixtures be reclassified from over-the-counter to prescription only availability. There is a rational basis for coformulating acetylsalicylic acid (ASA) and acetaminophen (paracetamol) as this reduces the dose of each, without altering efficacy. The coformulation of caffeine with these analgesics has a significant adjuvant effect and increases analgesic efficacy 1.4-1.6-fold. Currently available animal and human data do not support the notion that the nephrotoxic risk from coformulated ASA and acetaminophen is higher than the risk from either ASA or acetaminophen alone, in equivalent analgesic doses. There are no epidemiological data that implicate caffeine in AAN, and only limited evidence that links excessive acetaminophen usage to renal disease. There is no evidence that caffeine increases analgesics papillotoxicity directly. The presence of caffeine in mixtures of analgesics are no more addictive than other sources of caffeine. There is no evidence to suggest that adding caffeine to analgesic mixtures enhances the potential for promoting analgesic misuse in the general population. Thus distinct therapeutic benefits of ASA, acetaminophen and caffeine appear to outweigh any known risk. It is doubtful if preventing the availability of these products will significantly affect the role of analgesic abuse/overuse in end-stage renal disease. Better risk management would come from a focused educational program, developed in a close collaboration between industry, healthcare professionals and consumer organizations, such a program must warn against the potential dangers of analgesic and non-steroidal anti-inflammatory drug misuse.

A review of epidemiologic studies of nonnarcotic analgesics and chronic renal disease

The relationship of long-term and heavy exposure of nonnarcotic analgesics to the risk of chronic renal disease (CRD) has been the object of intensive clinical, pharmacologic, toxicologic, and epidemiologic research for 4 decades. The clinical evidence of an increased risk has been suggestive but inconclusive. The experimental evidence in animal models has been inconsistent, and in any case it cannot be generalized to humans. The epidemiologic evidence has been unsatisfactory for the most part: most of the early studies had severe methodologic limitations; moreover, they related mainly to phenacetin-containing drugs and did not have useful information on other analgesics. Since 1980, 9 analytical epidemiologic studies have attempted to confirm that a causal relationship exists between phenacetin or other analgesics and CRD. In the aggregate, despite methodologic flaws, this work suggests that excessive use of phenacetin-containing analgesics probably causes renal papillary necrosis and interstitial nephritis. In contrast, there is no convincing epidemiologic evidence that nonphenacetin-containing analgesics (including acetaminophen, aspirin, and mixtures of these two compounds) or that nonsteroidal antiinflammatory drugs cause CRD. Moreover, the nature of dose-response relationships, the types of renal disease possibly caused by analgesics, and the cofactors that might be related both to analgesic use and to the development of CRD in humans are still uncertain, and the pathologic mechanisms of analgesic-induced CRD in humans remain unclear. It may take many years before all the outstanding issues are settled. Until they are, as a matter of good clinical judgment it would be prudent to consider all analgesics as potentially nephrotoxic and, as much as possible, to avoid excessive, protracted use.

Morbidity of patients with analgesic-associated nephropathy on regular dialysis treatment and after renal transplantation

In a retrospective study, patients with end-stage renal failure from analgesic-associated nephropathy - 55 on regular dialysis treatment and 12 after renal transplantation - were under observation for 57 and 33 months, respectively. Of these 34 patients on chronic hemodialysis had suffered from different cardiovascular diseases. Hypertriglyceridemia was diagnosed in 62% of the patients, arterial hypertension requiring antihypertensive therapy in 44%. In three patients (5%) carcinoma of the urinary bladder were diagnosed. The leading causes of death in 21 patients included cardiovascular diseases (29%), hyperkalemia (19%), sepsis, and malignant tumors (14% each). Rejection occurred in 3 out of 12 patients after renal transplantation. Again, cardiovascular morbidity was high (58%) with coronary heart disease being present in 33% of the patients. Hypertriglyceridemia was observed in 5 out of 6 patients, antihypertensive therapy was needed in 50%. One patient died from primary pulmonary hypertension.

Health impact of renal disease due to nephrotoxicity

Both acute and chronic renal failure are reported in the context of nephrotoxicity. This overview of some major nephrotoxins reflects both the magnitude and the cost of this preventable health problem. Aminoglycosides and other antibiotics, contrast media and nonsteroidal anti-inflammatory drugs are the best documented nephrotoxins related to acute renal failure. Analgesic nephropathy is the best known drug-induced chronic renal disease. The cost of renal failure due to nephrotoxicity is not easy to compute. Drug-induced acute renal failure costs more than 2750 ECU per patient, depending on whether dialysis is required or not, and chronic renal failure costs at least 128,000,000 ECU annually in the European Communities. Recent epidemiological evidence, however, indicates that the cost may be even higher.