Abacavir: Its Use and Hypersensitivity (Clinical) (Clinical Report‪)‬

Abacavir (ABC), a nucleoside reverse transcriptase inhibitor (NRTI), combined with lamivudine (3TC), has a better short- and long-term outcome than 3TC combined with zidovudine (ZDV) as first-line HIV therapy. (1,2) In addition, children failing ABC/3TC-based first-line therapy do not select thymidine NRTI-related mutations, allowing for better choice in second-line therapy. (2) With current first-line options, both first-line (stavudine (d4T)) and second-line therapy (ZDV) include a thymidine-based NRTI, thus compromising second-line regimens. (3-5) In well-selected children, ABC is also an important drug in second-line and salvage therapy. (6) Of all the NRTIs, ABC is associated with the lowest rate of mitochondrial dysfunction. Types of dysfunction include lactic acidosis, peripheral neuropathy and lipo-atrophy. Substitution of d4T for ABC improves mitochondrial indices and reduces adipocyte apoptosis. (7) In adults, switching from d4T to ABC was superior to switching from d4T to ZDV. (8) In older children, once-daily use of ABC has also been shown to be effective, thereby facilitating adherence and improving patient satisfaction, particularly when all drugs are given once daily. (9,10)