Antiretroviral Therapy in HIV-infected Adults

HIV-infected AdultsOverview

Although the prevalence of acquired immunodeficiency syndrome (AIDS) in the U.S. continues to rise, there has been a concomitant decrease in AIDS-related morbidity and mortality as a result of advances in antiretroviral therapy. The efficient use of resources is necessary to ensure optimal patient care. To minimize the potential for developing resistance, initial antiretroviral regimens should maximally suppress viral replication.

After one or more regimens have been tried unsuccessfully, treatment costs may rise because of the increased use of tests (e.g., genotypic or phenotypic resistance assays) or because of disease progression. Therefore, as a consequence of the intricacies of antiretroviral therapy and the importance of regimen adherence, it is essential for health care providers to educate themselves about the fundamental aspects of HIV therapy. official canadian pharmacy

Part 1 of this two-part series presents an overview of anti-retroviral therapy and the fundamental principles of care for adults and adolescents. Part 2, in September’s P&T, will focus on the agents approved within each drug class.

The Centers for Disease Control and Prevention (CDC) reported that through June 2001, approximately 784,000 adults and adolescents had AIDS in the U.S. and that almost 60% of

them died. Approximately 340,000 people are currently living with AIDS, and, according to 1999 estimates, up to 900,000 are living with HIV infection. The virus has affected certain populations disproportionately; of the 40,106 AIDS cases reported in 2000, 69% were among blacks and Latinos.

In addition to the human toll of HIV infection, the economic impact is notable, particularly in the area of drug costs. The advent of highly active antiretroviral therapy (HAART) in the mid-1990s revolutionized the care of HIV-infected patients. Dramatic declines were seen in HIV-related morbidity and mortality, even in patients with advanced disease, which led to a reduction in hospital costs.

Overall, cost reductions were partially offset by pharmaceutical expenditures, which rose greatly. According to Bozette et al., per-patient adjusted annual expenditures for HIV-related care in 1998 were $18,300, a substantial portion of which was for drugs.

The backbone of current HIV therapy consists of four classes of drugs (encompassing 16 different agents):

•   nucleoside reverse transcriptase inhibitors (NRTIs)
•   nucleotide reverse transcriptase inhibitors (NtRTIs)
•   non-nucleoside reverse transcriptase inhibitors (NNRTIs)
•   protease inhibitors (PIs)

Optimally, these agents are used as part of the HAART multidrug regimen (Table 1).

Table 1   Antiretroviral Agents Used for the Treatment of HIV Infection and AIDS

NRTIs NtRTIs NNRTIs PIs
sulfate (ABC) Tenofovir Delavirdine (DLV) Amprenavir (AMP)
Glaxo/SmithKline) (Viread®, Gilead) (Rescriptor®, (Agenerase®,
(ddI) Agouron/Pharmacia & GlaxoSmithKline)
(Bristol-Myers Upjohn) sulfate (IDV)
Squibb Immunology)  (EFV) (Merck)
(3TC) (Bristol-Myers Lopinavir
(GlaxoSmithKline) Squibb Virology) (LPV/RTV)
(d4T) Nevirapine (NVP) (Kaletra®, Abbott)
(Zerit canadian, Bristol-Myers (Viramune®, Boehringer Nelfinavir (NFV)
Squibb Immunology Ingelheim) (Agouron)
Zalcitabine (ddC) Ritonavir (RTV)
(HIVID®, Roche) (Abbott)
Zidovudine canadian (ZDV) (AZT, Saquinavir mesylate (SQV)
GlaxoSmithKline) (Fortovase® and Invirase®, Roche)

In 1992, the FDA revised its drug approval policy and accelerated the approval process for antiretroviral drugs. This has resulted in the extraordinary rapidity of drug approval and in the inundation of a constant flow of new information in scientific and clinical communities. As the number of HIV-infected patients grows and they age, an increasing number of health professionals will be interacting with them.

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