Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTI)

“Several antiretroviral agents , including amprenavir, efavirenz and enfuvirtide, have also been linked with HSRs; however, the best characterized reactions occur with nevirapine and abacavir…Nevirapine hypersensitivity can include any combination of fever, rash and internal organ involvement, but most commonly manifests as isolated rash within 6 weeks of initiating drug (mean delay 14 days [44,45]). Nevirapineattributable rash occurs at a rate of about 16% in clinical trials, and approximately 7% of patients discontinue treatment because of cutaneous events. Although rashes are mostly mild to moderate, a relatively high incidence of more severe cutaneous reactions, such as SJS (0.3%), has been reported with nevirapine…The abacavir hypersensitivity syndrome is a well characterized systemic inflammatory reaction that usually occurs within 6 weeks of initiating abacavir-containing therapy (mean delay 11 days), with an incidence of approximately 5% in clinical trials. It is associated with a more nonspecific range of clinical signs and symptoms than nevirapine HSR, including fever, malaise, gastrointestinal symptoms and respiratory symptoms, which can mimic other infectious and inflammatory causes. Rash is absent in about 30% of cases of abacavir HSR and is often a late feature. Rechallenge is associated with severe, rapid and potentially life-threatening reactions, and is therefore contraindicated”

““a young lady came in with the complaint of a 6-day history of painful rash over a majority of her body. She also complained of swollen and painful lips. She was put on TMP-SMX 3 months ago and began antiretroviral therapy about a week ago. The rash on the abdomen, arms, and legs looked almost on molluscum contagiosum. On the palms of her hands and the soles of her feet were purpuric lesions. Her lips were indeed swollen and there were weeping lesions present. I had no idea what was going on so I consulted Dr. Francine – one of the more senior clinicians that was present in the clinic. She had seen one case like this before and the final diagnosis was a reaction to Nevirapine (a component of her 3 drug regimen for HIV). We told her to immediately stop the Nevirapine and return to her treating physician for a different regimen of ART therapy…””