US adult treatment guidelines updated (May 2006)

The Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents was revised in May 2006.

Changes to these guidelines include new recommendations for resistance testing, treatment interruption, and HBV/HIV co-infection. Tables have been revised to include up-to-date information about drug interactions and about the lopinavir/ritonavir 200/50 mg tablet formulation (Meltrex).


The recommendation for genotypic resistance testing cover newly diagnosed individuals (whether or not they are considering ARV treatment) and all treatment naive patients before starting treatment. This was first included in BHIVA guideline in 2003.

The recommendation for starting treatment remains ‘ when CD4 count is 200-350 cells/mm3, and first-line therapy remains: efavirenz plus 3TC/FTC plus AZT/tenofovir; or lopinavir/r plus 3TC/FTC plus AZT.

One of the key differences between UK guidelines is the continued use of AZT as a preferred first-line choice of nucleoside, without any reference to recent research showing that AZT causes lipoatrophy. AZT remains unlisted as a cause of lipoatrophy in both the text and in the tables summarising side effects. Evidence supporting this risk was considered sufficiently strong for this caution to be introduced in the UK guidelines in July 2005.

Recommendations for management of patients coinfected with hepatitis B, includes not using 3TC, FTC or tenofovir as the only HBV-active treatment in HAART regimens, due to the risk of HBV resistance to these agents.

While BHIVA guidelines only recommend use of boosted-PI regimens, the US guidelines only recommend boosting atazanavir when used with tenofovir or efavirenz, and include un-boosted fosamprenavir as an alternative option.

The US guidelines also include several references to drugs that are now discontinued, including saquinavir sgc (Fortovase), ddC (zalcitabine) and amprenavir (Agenerase), though these may have been retained for historical reasons.

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