If taken 1 hour before indinavir (IDV), didanosine does not affect IDV exposure, despite persistent buffering effects.

Concurrent administration of indinavir and didanosine significantly reduces the level of exposure to indinavir, but it is unclear how soon after didanosine administration indinavir may be given safely. We compared indinavir pharmacokinetics and gastric pH in 12 human immunodeficiency virus-positive patients by use of 800 mg of indinavir alone versus 800 mg of indinavir administered 1 h after didanosine administration. Median gastric pH was significantly higher when indinavir was taken after didanosine administration; however, no significant difference in the maximum concentration in plasma or the area under the concentration-time curve from time zero to 8 h was observed. Indinavir may be taken with a light meal 1 h following the administration of 400 mg of didanosine.