People who achieve undetectable viral loads and high CD4 counts while using antiretroviral therapy may safely switch to a regimen that contains Viramune (nevirapine), say the authors of a study published in the March 15 issue of Clinical Infectious Diseases.
Current guidelines recommend that HIV-positive people with higher CD4 counts—women with greater than 250 cells and men with greater than 400 cells—who have never taken antiretrovirals should not take Viramune, as they are at increased risk of having a hypersensitivity reaction (HSR) that can cause severe rash and damage the liver. What is unknown, however, is whether a person whose CD4 counts are low enough to safely initiate Viramune, but who first started another antiretroviral regimen, can safely switch to Viramune if their CD4 increases beyond those recommended by treatment guidelines.
Ferdinand W. N. M. Wit, MD, of the Center for Infection and Immunity Amsterdam at the University of Amsterdam, and his colleagues examined the medical records of 11,592 HIV-positive patients enrolled in the AIDS Therapy Evaluation in The Netherlands (ATHENA) cohort study. They found 3,752 who had either started treatment with Viraume, or switched to it after using other agents, and had a CD4 count available before starting or switching to the drug. Of the patients evaluated, 25 percent started Viramune as part of their first antiretroviral regimen and 75 percent switched to Viramune after first taking another regimen.
Two hundred thirty-one patients discontinued Viramune because of an HSR, with 75 percent discontinuing due to rash, 21 percent due to liver toxicity, and 4 percent who had both a rash and liver toxicity.
Dr. Wit’s group confirmed that compared with patients with low CD4 cells starting treatment for the first time with a Viramune-based regimen, patients with low pretreatment CD4 counts—but high CD4s as a result of using a non-Viramune regimen—are no more likely to experience an HSR upon switching to a regimen that includes Viramune.
In people who started Viramune as part of their first antiretroviral regimen, the researchers found that HSRs were more common in women and people who had a high CD4 count before starting treatment. In people who switched to Viramune, HSRs were more common in people who had a high CD4 count before starting their first antiretroviral regimen and in people who had a low CD4 count before starting their first antiretroviral regimen but a detectable viral load before switching to Viramune.
The authors conclude that people who need to switch to a Viramune-containing regimen may do so safely provided that their CD4 count prior to their first regimen was within the guidelines for initiating Viramune, and that their virus is completely suppressed before switching.
