HIV and drug abuse: relationship and treatment challenges

Introduction: There is a close two-way relationship between substance use and the Human Immunodeficiency Virus (HIV). About half of HIV infected patients report alcohol or other drug use disorders in present or past days. This is associated with poor therapeutic adherence, immunosuppression and increased risk behaviours, leading to increased morbidity and mortality. It is known that the different substances also have a direct impact on the clinical evolution of HIV infected patients, both in terms of the course of the illness itself and in terms of possible pharmacological interactions.

Objectives: To understand the impact of substance use such as alcohol, opioids, cocaine, stimulants and cannabinoids on the clinical course of HIV infected patients, as well as the possible drug interactions between antiretrovirals (ART) and the drugs used to treat these additions.

Methods: Review of the literature from Pubmed database.

Results: From a biological perspective, evidence shows that substances such as alcohol, cocaine and other stimulants lead to increased viral replication in HIV infected patients and to immune defects responsible for the progression of the disease. In behavioural terms, risk behaviours and poor therapeutic adherence are responsible for a poor outcome. Among opioids, injected heroin is a recognised risk factor for HIV infection, and substitution therapies such as methadone or buprenorphine are known to be effective in its prevention. Patients with HIV infection who use substances present another challenge, which is the potential for drug interactions between ART and addiction treatments. This frequently leads to a lower prescription of drugs for the treatment of substance abuse. Studies show that disulfiram can be safely used with commonly prescribed ART (ritonavir, atazanavir and efavirenz); however, some of these ART can reduce the effectiveness of disulfiram and dose adjustment should be considered. Acamprosate and naltrexone seem to be safe with ART. In the case of methadone, there are potential interactions with ART (efavirenz) that can reduce its levels and lead to withdrawal symptoms.

Conclusions: The impact of substance use on HIV infection is undeniable. A better understanding of this interaction is of relevance, as well as a greater knowledge about possible drug interactions, so HIV infected patients are offered all treatment possibilities for drug addictions.