The use of nevirapine for post-exposure prophylaxis may carry a risk of serious adverse effects unless the normal 4 week regimen is shortened, experts warned at the 6th Annual meeting of the British HIV Association in Edinburgh.
Dr Paul Benn, reporting on the use of d4T/3TC and nevirapine as the standard PEP regimen in Camden and Islington Health Authority between 1997 and 1999, said that 9% of those who received a nevirapine-containing regimen had experienced serious adverse effects, including severe rash or liver toxicity. A nevirapine-containing regimen was no better tolerated than an indinavir-containing regimen overall, although fewer minor adverse events were seen in the nevirapine group.
Nevirapine has been proposed as a suitable drug for PEP because it causes less nausea and is less disruptive to everyday life than indinavir, the drug currently recommended in UK guidelines. However, a small proportion of people who take nevirapine can be affected by serious rash, which may require hospital treatment. Professor Brian Gazzard, commenting on the findings, suggested that nevirapine-containing PEP might be shortened, since rash tends to occur only after ten to fourteen days. "Perhaps we should be looking at adopting the HIVNET 012 protocol [one dose of nevirapine for the mother and one for the infant]. In the HIVNET 012 trial, infants did not develop rash after only two doses", he said.
The study also found one case in which PEP may have failed. One man who received nevirapine-containing PEP after a potential sexual exposure tested HIV-negative after three months but HIV-positive after six months. His infection source was receiving treatment with d4T/3TC and nelfinavir at the time of the exposure, and the seroconverter had two secondary PI-associated mutations when tested for drug resistance. However, no nucleoside analogue-related mutations were detected.
The British HIV Association will be developing specific guidance about the use of various antiretroviral regimens for PEP during the course of 2000.
Benn P et al.HIV post-exposure prophylaxis (PEP): a retrospective review. Sixth Annual meeting, British HIV Association, abstract 08, 2000.