Current U.S. Guidelines state that Viramune (nevirapine) should not be started in women with CD4s above 250 and in men with CD4s above 400. This is due to potentially severe allergic reactions found mostly at higher CD4 counts. However, there's no guidance around switching someone to a regimen with Viramune after already having been on treatment for awhile.

In 2010, the European Medicines Agency, who reviewed data from more than 12,000 patients in several large studies such as EuroSIDA, ATHENA and others, now recommends that women and men can switch to Viramune regardless of their CD4 counts provided that their viral loads are undetectable. Sometimes Viramune may be a better choice for certain individuals due to the side effects, drug interactions or resistance with other drugs.

People who wish to switch to Viramune should consult their doctors and weigh the pros and cons with this information. This change was not incorporated into the latest update to the U.S. Guidelines in January 2011.