Two doctors from San Francisco have written a review article describing the effects of recreational drugs on sexual risk taking, HIV disease progression and HIV treatment. The article, which was published in the 15th May edition of Clinical Infectious Diseases concludes that studies into the effects of drug use are difficult to carry out and that many questions remain unanswered by research.
However, they encourage healthcare workers to ask patients about their drug-taking behaviour and to advise them on how to reduce the risks associated with drug use and its effects on sexual behaviour and adherence to HIV treatment.
The writers concentrate on the ‘club drugs’ methamphetamine (‘crystal meth’), ecstasy, ketamine, gamma-hydroxybutyrate (GHB) and inhaled nitrites (‘poppers’), noting that the number of people taking these drugs is high among gay men - and that HIV-positive gay men tend to use more drugs and take them more often than those without HIV.
They also point out that drug use is a public health concern. In the United States, hospital admissions associated with drug use have increased dramatically, with emergency hospital visits increasing 35-fold due to ketamine use, and 60-fold due to GHB use between 1994 and 2001. Although serious medical problems following ecstasy use are infrequent, hospital visits increased 22-fold over the same period.
Risky sexual behaviour
The authors explain that a number of studies have attempted to examine the relationships between drug use and sexual behaviour. However, these studies are notoriously difficult to carry out: it is difficult for researchers to work out when drug use took place in relation to sexual risk taking; drug users often use more than one type of drug in a session; and other factors related are often not taken into account, such as where drugs are taken, where sex happens, the types of sexual partners drug users choose, and the presence of other conditions that may affect behaviour, such as depression.
Despite these difficulties, many studies have detected links between risky sex and drug use, particularly of methamphetamine and poppers. These drugs have also been associated with an increased risk of contracting sexually transmitted infections, including HIV.
The possible reasons for this are varied, including reduced inhibitions following drug use, resulting in more sex partners, having sex more frequently and less condom use. There is also evidence that drug use may lead to people having sex for longer periods, greater damage to the lining of the rectum, vagina or mouth, and suppression of the immune system, all of which could increase infection rates.
Drug use and HIV
Studies examining the effects of drug use on HIV disease are also difficult to carry out. Although test tube studies have shown that methamphetamine, ecstasy and poppers can affect immune cells, “no studies have demonstrated conclusively that club drugs directly influence the progression of HIV disease,” write the doctors.
In contrast, there is more evidence that drug use may be linked to poor adherence to HIV medications. This may be a particular problem for methamphetamine users, as binges of methamphetamine use can sometimes last for days, during which patients may fail to take their anti-HIV drugs. “Such sporadic treatment interruptions could lead to the development of drug-resistant HIV and, potentially, to treatment failure,” the authors explain.
Possible interactions between recreational drugs and anti-HIV medications have also received some research attention. Since these drugs are cleared from the body by similar routes, there is a risk that antiretrovirals, particularly protease inhibitors, can lead to elevated levels of recreational drugs in the body. The authors mention individual cases of very high doses of ecstasy and GHB in patients taking ritonavir (Norvir), with at least one death attributed to very high ecstasy levels. However, these isolated cases must be balanced against the large number of people who have taken these drugs together without suffering adverse effects.
Recommendations for healthcare providers
The writers conclude by calling for healthcare workers to ask patients about their drug use behaviour, and to inform them of the risks associated with different drugs in the short and long term. They recommend advising drug users on how to minimise these risks, by ensuring they drink enough fluids during a drug-taking session and avoiding dangerous drug combinations, such as GHB with alcohol and poppers with sildenafil (Viagra) or other impotence drugs.
They also recommend reminding drug users about safer sex and the need for high levels of adherence to anti-HIV medications, as well as possible interactions between recreational and antiretroviral drugs. Finally, they point out that drug users who develop drug dependence may benefit from behavioural therapy to overcome their drug habit. Although the benefits of this approach have not been evaluated rigorously, a study called ‘Project MIX’ is currently underway in four cities in the United States. This randomised controlled study is examining whether group therapy can reduce drug use and risky sexual behaviour in a large group of gay men.
Colfax G et al. Club drugs and HIV infection: a review. Clin Infect Dis 42: 1463-1469, 2006.