ULSICRAL administration may reduce the extent of absorption (bioavailability) of the following drugs: cimetidine, fluoroquinolone antibiotics (ciprofloxacin, norfloxacin), digoxin, ketoconazole, phenytoin, ranitidine, tetracycline, quinidine, L-thyroxine and theophylline, so that these medications should be given 2 hours before the administration of ULSICRAL.