Loperamide reduces the bioavailability of saquinavir by about 50%, and saquinavir increases the bioavailability of
loperamide by about 40%. Tipranavir alone, and in combination with
ritonavir, reduces the bioavailability and
plasma levels of
loperamide and its metabolites.
Monitor patients to ensure that saquinavir remains effective. The increase in
loperamide bioavailability is not expected to be clinically significant in the case of saquinavir, but the decrease with
tipranavir may be of relevance, and
loperamide may become less effective.