A Guide to Primary Care of People with HIV/AIDS - Canadian Public ...

A Guide to Primary Care of People with HIV/AIDS
Chapter 13: Management of Substance Abuse
HIV/AIDS ISSUES
Can HIV transmission be prevented in active
substance abusers?
A comprehensive HIV prevention strategy in a primary
care practice includes interventions to provide drug
treatment, to take care of mental health problems, and
to prevent HIV transmission during drug use and sexual
activity. The primary care provider should routinely
screen for drug abuse and treat or refer for treatment
as quickly as possible. This is particularly important for
adolescents who are at high risk for HIV, hepatitis B and
C, and other infections. One study has shown that once
adolescents start injecting drugs, over 90% will become
infected with hepatitis C within 18 months. The
provider should also counsel patients who are actively
using drugs not to share needles with others and to take
advantage of programs that distribute clean needles.
Programs use the needle distribution strategy as a first
step to engage individuals who can then be encouraged
to accept medical and drug abuse treatment services.
When is an active substance abuser ready for
HIV treatment?
The most important clinical decision for successful
treatment of drug-abusing patients with HIV is deciding
when they are ready -- both substance abuse treatment
and antiretroviral therapy (ART). Patients fall into 3
categories: those who do not want treatment, those
who are ambivalent, and those who want treatment.
For patients who do not want treatment, the provider
should continue to be available with information on
HIV and drug abuse treatment until they are ready
to consider treatment. For those who are ambivalent
about treatment, time is well spent during several
clinical visits discussing the health issues of AIDS and
drug abuse until they are ready for treatment. For
patients who are ready for treatment the next step is
to assess what factors will affect their adherence (see
Chapter 7: Adherence to HIV Therapies). History of
injection drug use, race, gender, age, socioeconomic
status, level of education, and occupation are poor
predictors of medication adherence. Accurate predictors
of adherence are:
• The patient’s health beliefs
• Ease of access to health care providers
• Familiarity with the treatment setting
• Existence of a social support system
• Perceived support from clinical staff members
• Simplicity of medication regimens
Interaction with providers and ambiance of the
treatment setting account for almost half of the support
factors needed to encourage drug users to adhere to
treatment regimens. This pattern is true for active drug
users, with the possible exception of persons addicted
to crack cocaine.
Difficult economic and social situations, including
unemployment and unstable housing, may make
adherence to clinical treatment plans for both drug
addiction and HIV even more difficult to follow. For
these reasons some drug abuse treatment centers
provide residential treatment to minimize outside
influences on drug use. Also, methadone clinics provide
an ideal opportunity for rehabilitated substance users
to receive adherence support for ART through directly
observed therapy (DOT) at the clinic.
What immunizations should drug abusers with
HIV receive?
Because of the higher risk of tetanus in injection
drug users, tetanus boosters should be given when
due. Pneumococcocal and influenza vaccines are
recommended for all patients with HIV. Drug abusers
with no antibodies to hepatitis A and hepatitis B should
be immunized. Hepatitis A can be fatal in individuals
with hepatitis C.
Are there important drug interactions
between antiretrovirals and medications for
drug treatment?
A common problem in treating patients with HIV
who are drug users is the drug interactions between
medications. Studies have shown that interactions of
methadone and antiretroviral medications are linked
to CYP450 3A4 sites in the liver. The most significant
interactions are between methadone and nevirapine
(NVP) or efavirenz (EFV), which precipitate rapid drug
withdrawal symptoms (see Table 13-7). Methadone
programs should be alerted when methadone
patients are started on efavirenz or nevirapine, as
dose escalation of methadone will probably be
required. When methadone and didanosine (ddI)
are coadministered the uptake of didanosine may be
lowered requiring a higher dose of didanosine (See
Drug Tables 7 and 8 in the Pocket Guide). Other
interactions caused by drugs such as abacavir
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U.S. Department of Health and Human Services, Health Resources and Services Administration, HIV/AIDS Bureau
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