Comparison of two HIV postexposure prophylaxis regimens among men who have sex with men in Amsterdam: adverse effects do not influence compliance

To compare 2 regimens for HIV postexposure prophylaxis (PEP) as to safety, adherence, outcome, and follow-up in men who have sex with men (MSM) in Amsterdam. Since 2000, all MSM starting HIV PEP in Amsterdam have been followed in 1 location. The regimen was comprised of zidovudine or lamivudine and nelfinavir (regimen 1) until 2005, when nelfinavir was replaced by atazanavir (regimen 2). All patient data, including data on PEP side effects and testing for alanine aminotransferase (ALT), were systematically recorded and compared between the 2 regimens from 2000 to 2007. HIV PEP was prescribed 309 times to MSM. Of the 261 who were followed up, 237 (91%) completed their 28-day course. Although fewer patients had diarrhea on regimen 2 than on regimen 1 (P = 0.00), the proportion completing either course was the same: 98 of 110 (89%) and 139 of 151 (92%), respectively (P = 0.42). Only 1 patient with severely elevated ALT was advised to stop PEP, he also had serious illness. MSM at least 30 years of age and MSM who had sex with a partner known to be HIV-positive completed their course significantly more often than those under 30 and those who had sex with a partner of unknown HIV status (P <0.005). Of MSM who completed PEP, 5 seroconverted for HIV despite good adherence to PEP. None of their viruses were resistant to the PEP regimen used. No difference in adherence was found between the 2 regimens, even though fewer adverse effects were reported on regimen 2. ALT need not be routinely tested to monitor adverse effects. The 5 seroconversions were not likely caused by PEP failure, but rather by ongoing HIV exposures