Medication-assisted Treatment of Drug and Alcohol Abuse and Dependence for People with HIV

		SUMMARY: Injection drug users (IDUs) and alcoholics often receive a late diagnosis of HIV and thus have more advanced disease and poorer outcomes than other groups of HIV positive patients. But patient-centered models of care and integrated services -- such as medication-assisted treatment of drug/alcohol dependence, psychosocial support, and antiretroviral therapy (ART) provided at a single site -- can lead to improved outcomes, according to a review published in the January 28, 2010 issue of AIDS. The study authors presented an overview of medication-assisted drug/alcohol treatment (e.g., methadone or buprenorphine) and discussed some model healthcare delivery programs now being developed.

By Liz Highleyman

"The intersection of the twin epidemics of HIV and drug/alcohol use results in difficult medical management issues for the healthcare providers who work in the HIV prevention and treatment fields," R. Douglas Bruce from Yale University School of Medicine and colleague noted as background. "Injection drug users are frequently disenfranchised from medical care and suffer stigma and discrimination creating additional barriers to care and treatment for their substance use disorders as well as HIV infection."

The authors distinguished 2 conditions that are often confused. Substance abuse is "a maladaptive pattern of substance use manifested by recurrent and significant problems and consequences related to repeated substance use" such as legal or interpersonal problems. Substance dependence is "a clinically significant impairment or distress related to substance use that includes three or more of the following symptoms: repeated use results in tolerance...withdrawal symptoms relieved when the substance is taken, the substance is taken for longer periods or in larger amounts than intended, persistent efforts to reduce or discontinue use fail, increasing time spent obtaining the substance and recovering from its effects, having daily social, occupational, or recreational activities reduced due to drug seeking and use, and continued use despite recognizing the role of substance use in psychological or physical problems."

"Exposure to addictive substances is widespread in society, but vulnerability to abuse and dependence is behaviorally complex as a product of biological/genetic, psychological and environmental interactions and influences," they wrote. "Substance abuse and dependence is a complex physiologic, social, and behavioral disorder that often coexists with psychiatric and comorbid medical illnesses."

The authors reviewed medications used in treatment of substance use disorders, including methadone and buprenorphine for opiate/opioid substitution therapy; naltrexone, an opioid receptor antagonist than helps prevent opiate or alcohol relapse by blocking the "high"; acamprosate, which may help reduce craving; and disulfiram (Antabuse), which helps prevent alcohol relapse by causing unpleasant symptoms such as nausea.

Buprenorphine (a partial opioid receptor agonist) may be preferable to methadone (a full agonist) for people with HIV because it is safer with regards to overdose, causes fewer adverse side effects, can be taken every other (rather than every) day, and HIV clinicians can provide it by prescription, unlike more strictly controlled opioids. However, some people with long-standing heavy drug use and high opioid tolerance may require methadone.

The Center for Substance Abuse Treatment (CSAT) and the Substance Abuse and Mental Health Services Administration (SAMHSA) maintain a treatment locator website at www.csat.samhsa.gov that can help patients and providers find appropriate treatment programs.

Turning to alcohol, the authors explained that alcohol dependence "compromises the effectiveness of HIV treatment by influencing access and adherence to antiretroviral therapy..." Treatment of alcohol dependence integrates psychosocial treatment and medications such as naltrexone, disulfiram, or acamprosate.

A potential drawback of medication-assisted substance disorder therapies for HIV positive people is their potential to interact with antiretroviral drugs. Non-nucleoside reverse transcriptase inhibitors (NNRTIs) and some protease inhibitors have been found to interact with methadone because they are metabolized by the same liver enzymes, potentially leading to withdrawal symptoms and necessitating methadone dose adjustment. Buprenorphine has fewer such interactions. Interactions between disulfiram and HIV medications are not well studied.

"Although interferon, which is utilized in the treatment of hepatitis B and C, has extensive symptom overlap with opioid withdrawal (e.g. flu-like symptoms), studies have not demonstrated a pharmacokinetic interaction," the authors noted. "In our experience, however, many patients will request increases in methadone dose due to these symptoms."

The authors mention the use of bupropion (Zyban, Wellbutrin) and varenicline (Chantix) to aid smoking cessation, directing readers to an updated guide on treating nicotine dependence published by the Office of the Surgeon General. There are currently no FDA-approved medication treatments for abuse of stimulants such as cocaine or methamphetamine.

Antiretroviral medications can interact with benzodiazepines, sedatives that are both prescribed for therapeutic purposes and used recreationally. Some of these drugs -- as well as ecstasy and related compounds -- can potentially interact with antiretroviral drugs, though reports of serious adverse affects are rare.

"Patient-centered models of care that promote care and treatment of individuals who abuse or are dependent upon drugs/alcohol address those most disenfranchised in our society who most often receive a late diagnosis of HIV infection with a resultant poor clinical outcome," the review authors concluded. "Model healthcare delivery programs are being developed and piloted and include an integrated model with onsite addiction/HIV treatment; a HIV primary care treatment model; a non-physician healthcare model; and a community outreach model."

"The implementation of such models of care and their incorporation of medically-assisted treatment will substantially impact the HIV epidemic in the United States that continues to affect racial and ethnic minorities at a disproportional level and is increasing among men who have sex with men," they continued. "These models of care will allow the medical community to provide comprehensive medical care for substance users and manage their other chronic diseases, most notably, cardiovascular disease, renal disease, diabetes, non-AIDS defining cancers and enhance their quality of life though preventive lifestyle changes including smoking cessation, weight loss, exercise programs and diet modifications."

Yale University School of Medicine, New Haven, CT; Center for Substance Abuse Treatment, Substance Abuse and Mental Health Services Administration, Rockville, MD; Department of Psychiatry, University of California, San Francisco, CA.

2/5/10

Reference
RD Bruce, TF Kresina, and EF McCance-Katz. Medication-assisted treatment and HIV/AIDS: aspects in treating HIV-infected drug users. AIDS 24(3): 331-3404 (Abstract). January 28, 2010.