ior, including self-reported sharing of needles and syringes, unsafe injecting and disposal practices, and frequency of injection. Sterile needle and syringe access may include needle and syringe exchange (NSE) or the legal, accessible, and economical sale of needles and syringes through pharmacies, voucher schemes, and physician prescription programs. Other components of multi-component HIV prevention programs may include outreach, education in risk reduction, HIV voluntary counseling and testing, condom distribution, distribution of bleach and education on needle disinfection, and referrals to substance abuse treatment and other health and social services. If sterile needle and syringe access is not available, IDUs can prevent HIV transmission if they properly use bleach to disinfect injecting equipment. Finally, outreach and education reduces self-reported drug-related risk behavior, and is an important and effective strategy for encouraging behavioral change, providing education on preventing HIV transmission, and referring IDUs to other health and social services.
Yet knowledge gaps remain regarding the effectiveness of some HIV prevention programs among IDUs. More research is needed to identify the additional benefits and cost-effectiveness of adding psychosocial interventions to opioid agonist maintenance treatment for opioid-dependent people in high-risk countries, and to determine the relative effectiveness of those interventions in particular cultural contexts and patient subgroups. Research is also needed on the relative effectiveness of various psychosocial interventions in treating opioid dependence in situations where opioid agonist maintenance therapy is not available or accessible. Finally, research is needed on the effectiveness of naltrexone for different patient populations and in different settings.
For non-opioid dependence, research is needed regarding effective pharmacotherapies for stimulant abuse, particularly amphetamine-type stimulants, which have emerged as a major problem in many parts of the world. In addition, there is a need to develop cost-effective and feasible alternatives to voucher-based contingency management approaches for treating stimulant dependence.
Related to sterile needle and syringe access, several areas deserve future research. For example, information on unintended consequences from needle and syringe exchange—such as the possibility of recruitment of new drug users and expansion of drug networks—is scarce. Although the few studies that have examined unintended consequences have not found them, future evaluations should look specifically for unintended outcomes, and—if found—develop strategies for addressing them.
In addition, while laboratory studies have shown that undiluted bleach is an effective disinfection agent, field studies show that, in practice, drug users do not correctly follow disinfection procedures, and that they fail to effectively disinfect syringes. More research is therefore needed on alterna-