It is likely that
phenobarbital and other barbiturates will increase the
metabolism of the
protease inhibitors, thereby reducing their levels and possibly resulting in antiretroviral therapy failure. However, one case suggested that this may not have occurred when
primidone was given with ritonavir/saquinavir, although this should be viewed with caution.
The combination of
protease inhibitors and barbiturates should be used with caution. Monitor for
antiviral efficacy.