Black Tar Heroin: Lower HIV Transmission vs Higher Bacterial Infections?

ResearchBlogging.orgWound botulism has always been a problem in injecting drug users (IDUs), especially those that have been using what is known as the Black Tar Heroin (BTH). BTH is actually incompletely acetylated morphine. Diacetylmorphine is the completely acetylated form, which is known as heroin. Incomplete acetylation leads to formation of a mixture of 6-monoacetylmorphine (6-MAM) and 3-MAM, which is black or dark brown in color, depending on the purity of the production process. At best, when lactose is used as a “cutting agent”, the drug takes the form an even, brown powder, and at worst, when cut using boot polish or dirt or other such adulterants, take the form of a black, tarry goo. The latter form is more commonly used as it is cheaper and can be done in any ordinary settings without the need of advanced equipment required for crystallization processes.


Naturally, considering the crude method behind the production of BTH, it has overtaken purer forms of heroin as the preferred street drugs in many areas. Often, BTH may congeal into a semi-solid, non-injectable form, which then needs to be heated to melt it. IDUs also need to clean out the syringes before and after using because the risk of the goo congealing in the needle and making the syringe unusable is high. Also, since the consistency of the drug evokes a strong thrombophlebitic and sclerotic response in veins, it causes very rapid venous sclerosis, which makes repeated intravenous injections difficult, therefore, encouraging subcutaneous injection of the drug (also known as skin popping). Now, it has been alleged that these practices, put together, may lead to a slight lowering of risk of HIV transmission in the users of BTH. In an interesting paper[1], Ciccarone and Bourgois contend that:

Distinct physical and chemical types of street heroin exist worldwide, but their impact on behavior and disease acquisition is not well understood or documented. This article presents a hypothesis to explain the unequal diffusion of HIV among injection drug users in the United States by examining the distribution and use of one type of heroin—“Mexican black tar.” Drawing on ethnographic, clinical, epidemiological, and laboratory data, we suggest that the chemical properties of black tar heroin promote the following safer injection practices: (1) the rinsing of syringes with water to prevent clogging; (2) the heating of cookers to promote dissolution; and (3) a rapid transition from venous injection to subcutaneous or intramuscular injections.

However, these very practices, and the fact that the BTH is cut in unsanitary conditions with possibly contaminated materials like dirt, honey or shoe polish[2,3], makes it a high risk substance predisposing to bacterial infections, particularly those that spread through spores as those may withstand the heating and washing processes that possibly helped in reducing HIV rates. Necrotizing fasciitis has been a known and devastating complication of using this drug. Bacterial infections, especially those with Clostridium have been documented time and time again, and especially in clusters, amongst users who have shared a common infection source, notably, a badly cut batch of BTH.

photomicrographic view of a gentian violet-stained culture specimen revealing the presence of numerous Gram-positive Clostridium botulinum, formerly known as Bacillus botulinus, bacteria and bacterial endospores. (PHIL 2107)
Photomicrographic view of a gentian violet-stained culture specimen revealing the presence of numerous Gram-positive Clostridium botulinum bacteria and bacterial endospores. (PHIL 2107)

More recently, there has been at least three identified cases of wound botulism in injectable BTH users in California (Outbreak News), the news of which prompted me to make this post. California, for some reason, has been the epicenter of BTH associated wound botulism in the recent past, with as many as 50 identified cases since 2009. Wound botulism, caused by infection with Clostridium botulinum, can be a fatal infection unless handled urgently. This makes it no worse an alternative for the purportedly reduced HIV transmission!

Either ways, viral or bacterial, there is no good news or respite for the injectable drug users.


1. Ciccarone, D., & Bourgois, P. (2003). Explaining the Geographical Variation of HIV Among Injection Drug Users in the United States Substance Use & Misuse, 38 (14), 2049-2063 DOI: 10.1081/JA-120025125

2. Werner SB, Passaro D, McGee J, et al. Wound botulism in California, 1951–1998: recent epidemic in heroin injectors. Clin Infect Dis 2000;31:1018–24.

3. Passaro DJ, Werner SB, McGee J, et al. Wound botulism associated with black tar heroin among injecting drug users. JAMA 2000;279:859–63.

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