Impaired bioavailability of famotidine given concurrently with a potent antacid

The effect of a high potency antacid on the oral bioavailability of a single dose of famotidine (40 mg) was evaluated in normal volunteers according to a randomized cross-over design. Ingestion of the antacid concurrently with famotidine resulted in a significant reduction of peak plasma famotidine concentration (from 156 ± 22 to 104 ± 7, P <0.05) and area under the famotidine plasma concentration curve (from 956 ± 125 to 607 ± 56, P <0.02). No significant interaction was observed when the antacid was ingested 2 hours after famotidine administration.