I found this on the express scripts drug info website:
<div class="FTQUOTE"><begin quote>What drug(s) may interact with lansoprazole? (Back to top)
.ampicillin
.bisacodyl
.delavirdine
.digoxin
.fluvoxamine
.iron salts
.itraconazole
.ketoconazole
.sucralfate
.theophylline
.voriconazole
Tell your prescriber or health care professional about all other medicines you are taking, including non-prescription medicines, nutritional supplements, or herbal products. Also tell your prescriber or health care professional if you are a frequent user of drinks with caffeine or alcohol, if you smoke, or if you use illegal drugs. These may affect the way your medicine works. Check with your health care professional before stopping or starting any of your medicines.</end quote></div>
<div class="FTQUOTE"><begin quote>What drug(s) may interact with lansoprazole? (Back to top)
.ampicillin
.bisacodyl
.delavirdine
.digoxin
.fluvoxamine
.iron salts
.itraconazole
.ketoconazole
.sucralfate
.theophylline
.voriconazole
Tell your prescriber or health care professional about all other medicines you are taking, including non-prescription medicines, nutritional supplements, or herbal products. Also tell your prescriber or health care professional if you are a frequent user of drinks with caffeine or alcohol, if you smoke, or if you use illegal drugs. These may affect the way your medicine works. Check with your health care professional before stopping or starting any of your medicines.</end quote></div>