Experience with PEP finds most patients stop early
Some get free drugs in British Columbia
A high level of intolerance for drug regimens and difficulty in getting patients treated early enough are major barriers to effective post-exposure prophylaxis (PEP) for non-occupational HIV exposures, say those who have experience with the practice.
Although the federal government has issued no guidelines for PEP in cases of high-risk sexual or injection-drug exposures to HIV, several hospitals regularly provide preventive therapy for patients the same way they do for health care workers.
And in British Columbia, PEP has been available for more than a year in each of its 70 emergency rooms for not only health care workers, but also for firefighters, police officers, paramedics, sanitation workers, and house staff in hotels, says Alistair McLeod, MD, chief of the committee on accidental exposures for the Center for Excellence in HIV/AIDS in Vancouver.
One of the motivations for starting the accidental exposures program was the experience of a colleague at the center who seroconverted after a minor needlestick injury, McLeod tells AIDS Alert. "That really got our attention because it didn’t seem that such a little bitty needlestick was an injury you needed to take drugs for," he says.
The emergency rooms provide PEP starter kits containing five days’ worth of zidovudine (AZT) and lamivudine (3TC), which allows people suffering accidental exposures to HIV to receive treatment as soon as possible. The course of treatment is 28 days and is free, McLeod says, adding that three drugs are offered for serious exposures.
The program doesn’t provide free drugs for exposures resulting from consensual sex and injection drug use, although PEP is available for such cases at a cost. Canadian health officials have not been unwilling to extend free drugs for exposures outside the existing guidelines, he adds.
"Why? Because we can’t make the judgments that are necessary to solve those problems," he says. "If a woman picks up trash and sticks herself, we can make a judgment call on that."
McLeod says "hundreds" of kits have been provided so far. Once the patients are started on the treatment, they can receive the rest of the regimen through their provider. He estimates that more than half of those who undergo PEP discontinue early.
Early discontinuation of PEP also is widespread among patients in the United States. In Boston, about 30 people have inquired about PEP and five have undergone therapy, said Kenneth Mayer, MD, director of the Brown University AIDS program in Providence, RI. Of those five, two could not complete therapy, he added during a recent conference on PEP.
The experiences are similar to those of health care workers. At San Francisco General Hospital, a total of 37 workers have been treated for occupational exposures with either double- or triple-drug combinations, reported Mitch Katz, MD, an AIDS researcher at the San Francisco Department of Public Health. Of the 28 patients who have taken AZT and 3TC, only 57% completed the 28-day regimen. Nine patients have taken AZT, 3TC, and indinavir, but only five completed therapy, he reported.
"The numbers are not trivial," he said, adding that two patients who stopped treatment suffered liver function abnormalities.
Another barrier to effective treatment, Mayer said, is the fact that about half of the 30 people inquiring about PEP in Boston came in more than 72 hours after exposure the maximum time most researchers say PEP remains effective. Among the five treated patients, one was not treated within the 72-hour window period because the hospital could not get the drugs in time, he added during the conference.
Mayer noted that two cases treated were gay men who experienced broken condoms. The other cases involved sexual assault.
The two main concerns of people considering PEP have been the cost of the drugs (insurance companies only recently started covering occupational exposures) and fear that the exposure will appear on their medical records, Mayer said.
An unpublished 1997 survey of 327 gay men, among the first studies to investigate the psychological and behavioral characteristics of men who plan to use PEP, found that 3% had already used PEP and 26% planned to use PEP.1
Compared to men not planning to use PEP, those who planned to use PEP were younger, less educated, and had lower income levels, the authors note. These men also were more likely to have unprotected sex and have multiple partners.
Reference
1. Kalichman S, Tannebaum L, Nachimson D, et al. Post-exposure prophylaxis for HIV infection in gay and bisexual men: Implications for the future of HIV prevention. Submitted for publication.
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