The Effect of Increasing Gastric pH Upon the Bioavailability of Orally Administered Phosphonoformic Acid (Foscarnet)

Foscarnet is an antiviral compound. Laboratory studies have shown it to be active against HIV. However, only 12 - 22 percent of an oral foscarnet dose is absorbed by the body. Ranitidine suppresses gastric acid output, increasing gastric pH. Thus by increasing gastric pH (decreasing stomach acidity), less foscarnet is expected to be decomposed or broken down in the stomach. Thus, more foscarnet should be absorbed into the body.

Six asymptomatic HIV-infected males, or those with limited symptoms of early AIDS-related complex ( ARC ), will receive one dose intravenously of ranitidine in distilled water and one dose of placebo (distilled water alone), followed in 1 hour by foscarnet in oral solution. The order of ranitidine and placebo is randomized and the two foscarnet doses are separated by at least 72 hours. A nasogastric pH probe is placed on each morning of drug administration to monitor gastric pH.