One in five people starting HIV treatment with Atripla end up switching to another regimen within a year, often because of central nervous system (CNS) side effects, according to a report from clinicians at Chelsea and Westminster Hospital in London highlighted at the 51st Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) on Sunday, September 18, in Chicago.

Atripla has been a leading treatment option for people starting antiretroviral (ARV) therapy since the three-in-one fixed-dose combination tablet was approved in July 2006. For many people, however, the efavirenz in Atripla—the pill also contains tenofovir and emtricitabine—can cause a variety of CNS side effects, such as muddled thinking, sleep disturbances, vivid dreams, nightmares, mood changes and exacerbated depression. Though these side effects often disappear or mellow considerably after a few weeks of taking the drug, they can linger for some. 

To determine the frequency of switches because of CNS side effects, the Chelsea and Westminster health care providers conducted a file review of 472 people living with HIV who started therapy for the first time using Atripla. In those who discontinued, data was collected on the duration of therapy and reasons for switching. 

Ninety-four percent of the patients reviewed were male, averaging 37 years old. Seventy-five percent were white, and slightly more than half were known to be men who have sex with men. 

Atripla was highly effective. Among the 383 people who completed 12 months of Atripla treatment, 98 percent had undetectable viral loads and their CD4 counts increased from 285 cells at baseline to nearly 450 after a year. 

Eighty-nine people, or 19 percent of the study population, discontinued Atripla within a year, with the average being 294 days after the fixed-dose combination tablet was started. CNS side effects were the most common cause for switching therapy, occurring in 63 (71 percent) of the evaluated patients. Other causes included liver toxicity (8 percent), rash (7 percent) and virologic failure and/or resistance (7 percent). 

Only 14 percent of the switches because of CNS side effects occurred during the first 12 weeks of therapy. Switches were more likely among those who continued to experience CNS-related problems from week 12 onward. 

“Individuals on Atripla are often required to switch antiretroviral therapy for adverse events,” the authors state in their conference abstract. “The [most common] reason in our cohort was for CNS toxicity, with the majority of cases occurring after more than three months.”

To learn more about ways to manage some of the CNS side effects of Atripla, click here.