health

HIV antiretroviral drug resistance is increasing. Unfortunately, it is difficult
to predict the likelihood of drug resistance in the source and the implications for
transmission. There are still relatively few data on the prevalence of resistance,
and the data are difficult to translate into PEP recommendations. Laboratory
evidence of drug resistance does not necessarily imply clinical drug failure.
However, a high or rising viral load in the absence of other causes (e.g., treatment discontinuation, intercurrent illness, or vaccination) strongly suggests that
drug-resistant virus may be present. Many experts believe that the PEP
regimen should include at least two drugs to which the source HIV strain(s)
are likely to be susceptible. While probably optimal based on virologic
considerations, this recommendation must be tempered by two particularly
critical considerations in prescribing PEP: drug toxicity and the complexity of
the regimen. Since the great majority of exposed persons will not become infected,
even if they receive no PEP, drugs used for PEP should have a very low incidence
of moderate or serious toxicity. They also should be well tolerated; incomplete
adherence due to unpleasant side effects could render a seemingly highly potent
regimen less effective than a less potent regimen. Some side effects that limit
adherence (e.g., nausea or diarrhea) can be managed with symptomatic therapy.
When a pregnant woman is exposed to HIV, the evaluation of risk and need for
PEP should be approached as with any other person who has had an HIV exposure.
The decision to use any antiretroviral drug during pregnancy should be made
following discussion between the woman and her health care provider regarding
the benefits and potential risks to her and her fetus. Since indinavir may cause
indirect hyperbilirubinemia, this drug should not be used in newborns or for PEP
in pregnant women if delivery is expected shortly. Efavirenz should not be used
during pregnancy.
When the HIV status of the source is unknown or the source cannot be identified,
decisions regarding appropriate follow-up and PEP should be individualized, based
on factors such as whether potential sources are likely to include an individual at
increased risk of HIV infection and the severity of the exposure. If additional
information becomes available, these decisions can be modified.